The tires that Hume rode to such great success were, in manner and function, nearly identical to the tubular tires that would dominate high-level cycling events for the century-plus to follow.

It turns out that a woven casing with a rubber tube inside it and a rubber tread strip on the outside is a pretty great way to make a tire, and it’s not a coincidence that Dunlop winds up being (largely) credited with the invention of the pneumatic tire as a result of this design. He wasn’t the first, though. Robert William Thomson beat Dunlop to the punch (and the patent office) by a few months with his tires, which were different in some important ways.

The Thomson tire design featured a leather outer carcass with a rubber tube inside, which was bolted rather than glued on to a proprietary carriage wheel. While this design wasn’t successful for some very obvious reasons – leather casing, lack of rubber tread – it did have one really interesting and useful feature; the tire was easily removeable.

In short order, Dunlop himself was back at the patent office with designs for a more easily removeable tire

…which looks one heck of a lot like the tires/rims on the bleeding edge of development today.

The Dunlop company eventually wound up acquiring the patents of another inventor, Charles Kingston Welch, who invented the wire-bead clincher tire. Welch also held a patent for “certain new and useful Improvements in Pneumatic Tires”, US612981A.

In the language of the patent, “This invention relates to improvements in pneumatic tires, and is equally applicable to double-tube, single-tube, and the socalled (sic) tubeless tires.”

Yes, Tubeless tires. In 1898.

There ain’t nothing new under the sun, especially when it comes to bicycles, and looking at some of the early developments in cycling technology can provide some really interesting insight into the products of today.

The Welch patent, for example, goes into detail explaining just how important a flexible tire sidewall is for maximum performance –

"In Dunlop racingtires (sic) or tires used on bicycles for riding at a
high speed it is usual not to cover with vulcanized rubber the whole
of the outer surface of the fabric or inexpansible jacket serving to
inclose and retain the air-tube, but to cover only the tread portion,
leaving the fabric at the sides of the tire bare, so as to preserve the
flexibility thereof, whereby these sides offer very slight resistance to
the continuous deformation or lateral expansion of the tire at the
point where it bears upon the ground."

In 1898 Welch understood the importance of tire carcass deformation characteristics in the performance of the tire. While this may seem like common sense to anyone likely to click on an article like this today, it’s worth noting just how much this basic piece of tire construction wisdom has really only penetrated into the general consciousness of bike racers – and even industry professionals – very recently. Roll back a few years and you were more likely to find people prioritizing weight then factors like compliance and hysteresis when attempting to maximize tire performance.
While light weight may sometimes correlate with light construction, they aren’t the same thing, and Welch was well aware of this…

"The chief object of my invention is to produce a pneumatic tire for
bicycle that will permit approximately the same speed to be
obtained as with the light racing-tires at present constructed and will
at the same time be suitable for use on ordinary roads and in wet
weather."

His solution to a light construction tire that was sufficiently robust for ordinary use? He proposed covering the fabric portion of the tire with a thin sheet “or membrane” of rubber. This rubber coating would protect the fragile sidewall while still allowing for the deformation necessary for high performance. But there’s more.

"I cover those portions of the tire that are adjacent to the wheel-rim
with a strip or ring or strips or rings of vulcanized india-rubber or
other suitable material, so as to form both a resilient and efficient
closure between the tire and the rim and also a protection against
chafing or wear that might arise from friction on the rim. These
strips or rings of indiarubber instead-of forming part of. the tire may
form part of or be attached to the wheelrun."

In other words, rim strips that provide for a seal between the rubber coated tire and the rim it is attached to. Something that looks an awful lot like this…

…a modern tubeless tire system.

When we dissect a current generation tubeless tire system, we wind up with three essential components, all more or less replicating areas of Moore’s concern. These are a rim, whether hooked or hookless, typically fitted with a rim strip to provide a “resilient and efficient closure”, a tire – essentially always of woven construction, with a rubber tread bonded on to it, and – and this is the interesting part – the sealant inside the tire.

Tubeless tires aren’t all the same, and the functions performed by the sealant vary accordingly. In a “true” tubeless tire, the tire, when inflated on a compatible rim, will hold air without any sealant. In this use case, the sealant is present simply to “seal” any punctures that may occur during operation.

With what is commonly called a “tubeless ready” tire, however, the tire/rim system will not hold air without sealant. The sealant not only acts to repair system failures due to puncture, it also “seals” the tire carcass itself, forming a (largely) impermeable layer on the inside of the tire. In essence, the sealant acts as a surrogate tube.

It’s worth noting that with almost all current sealants this surrogate tube is a *latex* tube. It really doesn’t matter if your latex tube has been deposited on the inside of your tire via sealant injection, or if it’s an actual discrete tube product, what matters is that it’s latex, and latex tubes are fast. They’re definitely faster than a butyl tube, and if you’re running a “true” tubeless tire, you’re very likely running with the functional equivalent of a butyl tube bonded to the tire sidewall.

Butyl rubber is extremely robust stuff, very chemically inert and impermeable to gases. This makes it an excellent product for application to a tire sidewall, and it is used as the inner lining in the vast majority of automobile tires. Unfortunately, when we’re dealing with the fractional horsepower output of a human being on a bike, the small rolling resistance penalty of a butyl tube (or tube surrogate) actually matters. When we look at the rolling resistance rankings of tubeless tires, the vast majority of them are of the “tubeless ready” variety, and this is a big part of the reason why.

Here's another reason.

The construction of a “tubeless tire” can be much “lighter” than that of a true tubeless one.

If a tire looks like this when you install sealant, what you’re seeing is the sealant seeping through the light, porous construction of the tire. Eventually, the sealant will fill the tiny voids in the tire carcass, the weeping will stop, and you wind up with not just a surrogate latex tube on the inside of the tire, but a tire that is suffused with latex sealant, and in the words of Charles Kingston Welch, a “membrane” that acts “to efficiently protect the said jacket from moisture or other deleterious influences without detriment to its flexibility”.

The post Tubeless Was Bike Tech First first appeared on Slowtwitch News.

Despite what the name might suggest, the new Wahoo KICKR ROLLR isn’t a set of rollers, at least in the traditional sense. What it is, is a rear set of rollers linked to a front wheel tray and an armature to hold the wheel in that tray.

It isn’t much of a stretch to say that the design of this product owes a lot to previous products like the Feedback Sports (nee SportCrafters)
and Cateye trainers, which themselves were essentially a set of traditional rollers with the front wheel roller removed and replaced with a dummy axle.

This wasn’t exactly a new idea either, as Companies like Vetta had produced rear roller/front wheel stand trainers decades ago, and traditional rollers combined with a front wheel stand probably came into use right about the first time someone fell of their rollers. Wahoo has added some significant spice to this recipe, however.

First of all, the ROLLR is a smart trainer. Ish. The ROLLR doesn’t have any internal capacity to measure wattage, but it does contain an electronic resistance unit. This resistance level can be controlled by the Wahoo app, or by any of the typical virtual training programs/apps on the market like Zwift, Fulgaz or Wahoo’s own SYSTM. The ROLLR will output a speed metric to those programs/apps, and receive resistance control from them, so you can ride simulated terrain or erg workouts. Or, well… erg-ish. Remember, no power meter in the ROLLR.

Unless you already have a power meter on your bike. If you do, then the ROLLR instantly becomes a fully fledged smart trainer, as it is designed to link to your existing power meter and use that signal as the wattage output stream to feed whatever app/program you are using to drive the ROLLR. This happens pretty darn seamlessly, and in fact I didn’t even realize it was happening when I first used the ROLLR. When I review a product like this, I like to try and set it up without reading any of the literature that comes with it first, just to see how intuitive everything is, and what potential pitfalls might be out there for the folks who never read manuals. Based on my experience in customer service, there are a lot of them.

In this case I was not only able to get up and running without referring to the manual, I was able to connect the power meters of two different bikes to the ROLLR in order to feed it power data without knowing it was necessary to do so, or that I *had* done so. That’s pretty darn seamless, and a pretty big check in the win column.

You do need to have a power meter that is Bluetooth or ANT compatible to make this work. As that is essentially all of them these days, it’s pretty safe to say that if you’ve got a power meter, you’ll be able to drive power to the ROLLR.

As easy as I found it to drive the ROLLR with my power meter, that paled in comparison to how easy it is to put a bike on the unit, and to switch between bikes. The resistance unit isn’t attached to the bike, it’s just a set of rollers that the rear wheel, well, rolls on, and the front wheel just sits in this tray…

…and is held in place by two jaws, that you adjust by turning the grey rubber-ish wheel above them.

It isn’t even necessary to adjust the height of the front wheel to level the bike (assuming you have the same diameter wheels/tires on the front and the rear). This makes taking a bike on and off the trainer incredibly quick and easy, easier than any other trainer I have used, literally one operation removed from the “put the bike on and ride” simplicity of rollers, while still completely removing the rather steep learning curve of those devices…

Once your bike is on the ROLLR and linked up to your power meter and whatever program you’re using to drive it, you find that it basically does all the things one expects of a current generation indoor smart trainer. Kind of.

The combination of nothing holding your rear wheel in place on the rollers but your bodyweight, and the way that the front wheel connects to the trainer means that your bike can – and will – move around underneath you quite a bit on the ROLLR. The first bike I tried had a very lightweight set of race wheels on it, and the amount of front wheel movement when I rode hard out of the saddle was, frankly, disconcerting at first. Hi-torque/low cadence and out of the saddle, the front of the bike felt downright rubbery compared to the trainer setups I have become used to, as it moved well over a centimeter side to side. Meanwhile, the rear of the bike behaved – surprise! – like it was on rollers, with the lateral motion one would expect.

Once I got used to this movement – and the subconscious voice screaming “you’re going to fall over sideways!” quieted down – I found that the degree of bike movement allowed by the ROLLR made for a really great ride experience, especially over longer duration rides. Rocker platforms and articulated front wheel stands have become the object of fascination for a fairly large and devoted segment of the indoor riding population, and the ROLLR absolutely deserves consideration by those who are sold on the benefits of these products.

When I rode identical Fulgaz courses of up to about three hours on both the ROLLR and a more traditional trainer setup, I definitely experienced less “felt” fatigue after the session on the ROLLR. Riding the full Kona Fulgaz course on both setups, I was too wasted to feel much difference between them immediately post-ride, but the days following each ride, all my recovery metrics were ever so slightly better post-ROLLR.

The comparison setup I used for these rides was an Ipad connected via Bluetooth to either the ROLLR or a Wahoo Kickr with a Kickr CLIMB in place of the front wheel, all driven mostly by the Fulgaz app, with occasional detours into Wattopia on Zwift.

One of the things I appreciate most about Fulgaz is that it allows you to tackle simulated versions of some of the classic steep road climbs of European grand tour racing, with extended pitches well into the double digits, both up and down. Sharp, steep climbing that will find most riders wanting to get out of the saddle, and of a length that most other virtual riding environments don’t provide. If you want to test how an electronic trainer will respond on a 45 minute long simulated climb, Fulgaz is hard to beat.

In this environment, the differences between the ROLLR and the KICKR really stood out. In some ways the ROLLR is much more like riding out in the real world – all that lateral movement! – but in others, the Kickr/CLIMB combo is. Perhaps unsurprisingly, having the front end of the bike move up and down courtesy of the CLIMB makes descending and climbing feel much more realistic, but in addition – and especially on descents – the way that the KICKR simulates system inertia also feels much more in line with riding in real life. Steep sections that would have me completely spun out well in excess of 120 RPM on the KICKR/CLIMB were quite comfortable to pedal through on the ROLLR.

Turn those steep pitches around, though, and that’s where things really got interesting. The ROLLR, being neither fish nor fowl, does not fix the rear wheel in place like a traditional trainer, and it doesn’t float the front wheel on top of a third roller, like a traditional set of rollers. The front wheel is fixed in place (at least vertically) and the rear wheel floats. The result of this is that the axle of the front wheel becomes a hinge upon which the rest of the bike rotates, even if ever so slightly. Moving up and out of the saddle when using the ROLLR would noticeably decrease tire contact, to the point that resistance became lower, and the efforts became easier.

It’s not that the tire was slipping – it wasn’t – it’s that by shifting my weight bias forward, I decreased the weight on the rear tire, which resulted in a decrease in rolling resistance with a concomitant decrease in the wattage necessary to turn the rollers at a given speed for a given resistance. This effect was pronounced enough that while maintaining a constant speed and cadence, I could watch the wattage number drop on my power meter as I slowly moved out of the saddle and forward, and go back up again as I returned to the seated position. On a simulated 15% climb doing 300 watts in the saddle, I could maintain the same virtual speed with roughly 20 watts less output out of the saddle.

Needless to say, this is a pretty significant amount. Significant enough that I’m left wondering what the ramifications might be for the use of this device in certain virtual bike racing environments. If you happen to have been following the latest Zwift weight doping news this effect might sound a little bit familiar. It seems like this just might be a wee bit of an analog cheat code for a digital game.

While we’re talking about the analog world, and size and weight… the ROLLR is a sizeable piece of gear. It weighs 50 pounds, and while the front/stand section can detach and telescopes for adjustment and storage, it’s still going to take up a fair bit of real estate in your training cave or living room.

The roller section of the ROLLR will accommodate just about any tire, and the clamp on the front stand fits a tire up to about a 55 section. That should allow for just about any gravel bike…

…but falls a fair bit short of what most folks are running on mountain bikes these days. This is a bit unfortunate, especially considering who I think should be pretty excited about this product. Namely, bike fitters.

The ROLLR is a bike fit cheat code, too. It literally takes seconds to put a bike on the unit, and it is completely format agnostic in terms of wheel/axle type. It just doesn’t matter at all whether you are running thru-axles, quick releases, or bolt-on track wheels. Things might get a wee bit noisy with knobby tires, but they will work fine. 700c Wheel? Fine. So is a 650. B or C. Doesn’t matter. It would probably take a little bit of finagling, but I’m pretty sure I could make the darn thing mate with a hand cycle. As it sits, you aren’t going to get a tandem on the ROLLR, but all it would take to do so is a single extension piece for the rail that connects the rear roller to the front clamp.

The ROLLR isn’t going to replace an adjustable fit bike for FIST style fits, but if you’re a fitter looking for a trainer to fine tune or adjust positions on existing bikes, this is the one you’ve been looking for. If you’re not a fitter, and you’re looking for something that is incredibly easy to use, will fit *most* of the bikes you might have in your stable without mucking about, and has a really enjoyable ride quality… game on.

The post The Wahoo KICKR ROLLR Isn’t Your Grandpa’s Set Of Rollers first appeared on Slowtwitch News.

The wait is over. Today Wahoo Sports finally unveiled the Speedplay POWRLINK ZERO power meter pedal.

The POWRLINK ZERO is available to order right now, in two different versions. A dual sided version with both left and right power retails for $999.99, and a single sided version with a left only power meter sells for $649.99. Euro prices are the same, €999.99 and €649.99. Weights for the two versions are listed as 276 and 250 grams respectively, and the dual sided version was bang on that number according to my scale. (Unpowered Speedplays with a 53mm spindles weigh 222 grams.)

There is a lot to talk about with this product, and we’re going to break it down into (at least!) two different articles. This being part-1, we’ll cover the physical aspects of the product and the basic specifications, and take a fairly deep dive into the pedal/cleat/shoe interface. Part-2 – after we’ve had a bit more time on the pedals – will delve into the accuracy and precision of the power meter.

Installing the pedals on your bike is a breeze. Slide the (included) pedal washers over the threaded portion of the pedal, grease the threads, thread pedals on to crank arms. The pedals are installed using a pretty standard 8mm Allen wrench, and a recommended tightening torque of 30nm. You should probably re-torque the pedals after your first ride, just to avoid any bedding-in issues that could result in wonky data.

The pedals are charged via contacts on the outside of the pod that interface with a pretty slick little charging clip.

Two charging clips are included with the dual-sided version of the pedals and, yes, they are USB-C. A USB-A to USB-C Y-cord is included with the pedals, which is a nice touch. There is no USB wall wart, but do you really need yet another one of those?

In form and function, this is exactly what Speedplay fans have been asking for all these years. It’s a ZERO pedal with a power meter inside. It’s not exactly a ZERO pedal, though.

The obvious difference is the sensor/transmitter pod on the inboard side of the pedal spindle, but that’s not the only change.

A standard ZERO pedal body is 17.2mm thick. The POWRLINK ZERO body is 19.9mm thick. This results in just over a millimeter increase in stack height with the power meter version. This is pretty close to the kind of difference you’ll experience switching between winter and summer socks, but the increase is there.

The POWRLINK ZERO axle is also ever so slightly longer.

The pedals used for this review measured out at 54.5 mm from the center of the pedal to the base of the threads. That’s 1.5mm more than the standard ZERO stainless pedals came in at, and it’s the equivalent of a pedal washer. Pedal washers are included with the pedals, and you’ll want to use them so you have to factor that in, too. That’s not much, but it’s enough that a fair number of people will probably want to adjust cleat placement to compensate. I definitely did. Luckily, lateral adjustment is in pretty good supply with the Speedplay cleats. It is important to note that this is the only spindle length Wahoo is offering on the POWRLINK ZERO at this time.

Cleats are, of course, included with the pedals, and they are identical to the ones that come with the standard ZERO pedals. As with the ZEROs, an assortment of shims is included to match the cleat mounting surface to the curvature of your shoe, as are the rubbery “aero” covers and surrounds.

The pedals automatically calibrate. Or they don't. See our publisher Dan Empfield's answer on this on our Reader Forum thread on the pedals. see Ray (DC Rainmaker) Maker's reply on that thread, 2 posts below Dan's.

The electronics pod on the pedal definitely has some shoe/cleat/pedal interface implications, and attention to detail is pretty important when installing cleats. The pod isn’t huge, but it’s there, and you don’t want it to come in contact with your shoes. Wahoo includes a set of 2.5 mm thick cleat shims with the pedals, and this is a smart addition to the package. My guess is a fairly large number of installations will require the shim to avoid shoe/pod contact, and it’s nice to find it right there in the box.

It isn’t safe to assume that you can use the same cleat setup with the Powerlink as you’re using with your current ZERO pedals, and if you use more than one pair of shoes, you will want to check them all. I use different shoes for indoor vs outdoor riding, and while my indoor shoes fit just fine on the Powerlink, my outdoor shoes… not so much.

I have a 3 degree valgus (yes, valgus, which is quite rare) wedge under my cleats on these shoes, and this is a problem. The wedge goes between the cleat and the 4-bolt to three bolt adapter, and it tilts the cleat interface in towards the crank – you guessed it – 3 degrees. This is just enough tilt to cause the cleat cover to rise up just a tiny little bit on the inboard side, and as a result it rubs on the tapered part of the transmitter pod. If I want to run these pedals with these shoes, I will need to either use a different style of shim that goes directly between the shoe and the 4> 3 bolt adapter, or modify the cleat cover to create more clearance. Cleat wedge users will want to look for this problem, especially those (rare) ones with valgus correction.

The cleats on my outdoor shoes are also just a bit more worn than the ones on my indoor shoes, and as a result, when I’m actually riding in them they have a little bit of “toggle” or medial/lateral angular movement. There’s plenty of clearance when the shoe is lying flat on the pedal…

But if I apply just a little bit of medial pressure, that clearance pretty much disappears.

…and the sensor pod makes contact with the shoe. Periodic inspection for the development of cleat toggle will probably be important for installations with close tolerances.

While we’re on the subject of close tolerances, it’s worth noting that there was a fair bit more margin for error on the 4-bolt pattern shoes I tried.

There’s likely to be a fair bit of variance between brands, but at least with the Bont shoes I used, the 4-bolt native shoe just set up much more easily with these pedals. No shims needed here!

As a final note on the cleat/pedal interface, it is definitely not a good idea to run these pedals with the covers removed from the cleats. I typically do this with the shoes I use for indoor riding, as sweat tends to collect in the covers and rust out the cleats fairly quickly. Unfortunately, if you take the covers off this will probably happen…

The tapered portion of the transmission pod runs smack into the sharp edge of the upper cleat plate when you rotate your foot to unclip, and that takes a nice little bit off the edge of the pod. Fair warning, keep the covers on.

It’s important to note that if you’re at all familiar with the standard Speedplay ZERO pedals, all of this is going to be a lot less imposing than it probably sounds like here. It took a lot more time to write all of this than it did to install the pedals, and correct for the small issues discussed here. The Speedplay system is definitely more complicated than something like a Look or Shimano system, but that complexity allows for things like precisely tuned float adjustment, simple compensation for leg length difference, and dual sided entry. All of these advantages are retained in the power meter version of the pedal. And it’s a power meter! If you’re a Speedplay user – and, cards on the table, I definitely am – you won’t be disappointed by any of the pedal aspects of these pedals.

The publisher of this site is a big fan of Speedplay and has been critical of power meters in pedals. His stated view is that a power meter should not take away from the proper function of a pedal (or hub, or crank for that matter). He's riding the POWRLINK right now, no clearance issues for him, using a pair of existing Speedplay-cleat-mounted Shimano RC9 shoes.

In his view, the POWRLINK passes the utility test because he believes so much of the value in Speedplay exists in the cleats. Also, I happen to know he rides a 56mm spindle in Speedplay, and the POWRLINK + pedal washer gets him exactly there.

In part two, we’ll dive into the power meter side. Above is a peek at some early numbers (we'll use DC Rainmaker's excellent analyzer). Here's more on the Speedplay POWRLINK ZERO.

The post Speedplay POWRLINK ZERO Pedals first appeared on Slowtwitch News.

If so, we might just have a solution for you.

We’re going to focus on flat mount brakes, as that format has become essentially ubiquitous on the tri/road/gravel frames of this current generation, but the general principles we will talk about apply to all disc brakes.

In order to function properly, a disc brake needs to be set up so that the pads are at the correct height for the rotor size chosen, are laterally aligned with the rotor, and move in the same plane as the rotor, which should be perpendicular to the hub axle.

We use adapters to adjust for the different rotor sizes/heights, and – thankfully – this doesn’t have to be perfect. When it isn’t you might notice a little bit of material at the top of your brake pads that doesn’t wear away as the rest of your pad does.

If your pads look like the one in the pic, it means your brake is mounted high relative to the rotor. The amount shown in the pic is pretty typical. Any more than that, and you should do something about it. That “something” is… complicated. More on that in a bit.

Lateral alignment is fairly simple, until it’s not. There is a certain degree of adjustability built in to the brake mounting hardware so that you can vary the lateral offset of the brake, and match the angle of the brake mechanism to the rotor.

In the rear, the brake mounts on the frame are elongated ovals.

The brake bolts slide from side to side inside these slots, and you clamp the whole thing down when everything is positioned correctly.
In the front, the slots are in the brake itself, the bolts are fixed in place in the frame, and the brake moves around them, once again being clamped in place once alignment has been achieved.

There’s limit to the adjustability this system affords, as It’s bound by the length of those slots. As limited as this range is, it should be plenty. If it isn’t, either your frame is out of spec or (perhaps more likely) your wheel/rotor is. For the nerdiest of us, an excellent breakdown of the technical specifications can be found here.

That covers vertical and horizontal alignment, and we’re left with angular alignment.

In theory, your brake rotor is mounted perpendicular to the axle of your hub. The plane of the rotor path is at a perfect 90 degree angle to the hub center. Your brakes need to operate in that same plane.

With old-style post mount brakes, there is a little bit of wiggle room to adjust the brakes so that alignment in this plane is correct. There is a little spherical washer set that goes between the post and the brake, and the brake pivots ever so slightly upon this until you tighten things down. You get maybe a couple of millimeters of adjustability out of this system, and that’s generally just enough to square things up.

Flat mount brakes don’t have any such adjustability. They rely entirely upon the (nominally) flat surface they bolt to being put in exactly the correct alignment by the frame manufacturer.

Perfection is a very rare thing. Even very high-end framesets from well regarded manufacturers can be found with brake mounts that are out of spec.

If your brake pads look like this…

…with the pad wearing asymmetrically or at an angle, or if you simply cannot get your brakes to set up without rubbing or squealing, or – and this is the big tipoff – if every time you try to adjust your brakes, just when you think things are perfect and ready to go, you apply that final bit of torque to the bolts to snug things down to spec only to find that the darn rotors are suddenly rubbing… if any of this sounds familiar, odds are your brake mounts are out of alignment.

Fortunately, there is a solution. You can grind those recalcitrant mounts into submission using a disc brake mount facing tool.

While it seems very clear that most people (even many bike mechanics) have never heard of these tools, they have been around for just about as long as disc brakes have been on bikes. This is the Magura Gnann-O-Matt Disc Optimizer, and being 20+ years old, it pre-dates both flat mount and post mount brakes, and is designed to “optimize” I.S. mounts on bikes with quick release dropouts.

You almost certainly have none of those things on your bike, so we’re going to have to use something a bit more modern. We’re going to use the Park Tool DT-5.2. The “.2” part of that name is important. If you’re going to buy one of these, you definitely want the 5.2. The DT-5 won’t work with flat mount brakes, it’s post mount only.

In theory, the operation of the DT-5.2 is fairly simple. An adjustable rod is placed in the dropouts of your frame/fork, where the hub would ordinarily sit. A vertical rod bolts on to this surrogate hub, and an articulated arm slides up and down on the vertical rod. At the end of the articulated arm is a rotary cutter head.

To index the cutters, you push two little plugs into the brake mount holes and drop the arms of the cutter head down on to the posts.

You hold the cutter head in place with your hand, then fix the vertical rod in place.

Now that you’re aligned, you remove the plugs, place the nub on the end of the cutter head inside the brake mount hole, and tighten down the articulated arm.

There is only one cutter head, so you need to move it between the two mounting holes, relying on a (non-indexed) collar that bolts to the vertical rod to keep the depth of cut consistent. Before cutting anything, you will want to figure out which of the two mounting slots is lower by measuring the gap on the vertical post.

You should first cut the lower of the two mounts, as both mounts will need to wind up at the same depth.

To cut, simply turn the blue knob. You’ll want to cut until enough of the surface is level to ensure stable contact when the mounting bolts are tightened down. I “blued” the surface of this mount with a paint pen so you can see what it looked like after the first few passes of the cutter…

…and when level. Ish.

This is the point at which I stopped. Why?

There are two mounting points. This was the higher of the two, and at this point I had reached the level at which the first mounting point was faced level and true. If I went any farther on this one, I would need to go back and re-cut the other. This is also sufficient surface area to be stable. Barely, but enough.

Most importantly, though, remember this picture?

This is what it looks like when the brake is sitting higher than the rotor. The solution to this problem is face/cut the mount deeper so that the brake sits lower.

With the one that I’m working on here, though, I’m approaching the opposite end of the spectrum. If I go much lower, I’m going to need to shim the brake up in order for it to contact the brake rotor correctly. So, good enough is good enough.

It should be pretty obvious from that first picture why it was more or less impossible to adjust the brakes on this bike. The mounting hole to the right was lower than the one on the left, and the brake was only making contact from about 9-12:00 on the left hand mounting surface. Every time this brake was tightened down, the brake would slide ever so slightly counterclockwise and down, taking the brake out of plane with the rotor. As a result, the brakes always rubbed ever so slightly, they pinged with most rotors, and they squealed if there was even a hint of moisture in the air.

After I completed this process, I bolted everything back in place and it’s like it’s a different bike. Brake adjustment takes seconds, the brakes don’t squeal anymore, and a (frankly) unpleasant setup has become one that is a pleasure to work on and to ride.

Based on personal experience and an informal survey of working bike mechanics, very few bikes have their brake mounts properly faced at the factory or at point of purchase, and a huge percentage of the problems that people commonly encounter with their disc brakes can be at least in part addressed via this process.

This isn’t rocket surgery, but it is a bit much for the average home mechanic. You want to have the process down pat before you even think about mounting a cutting tool on an expensive frame, and the list price of the Park DT-5.2 is $469.95. Those two things combine to put this pretty squarely in “contact your local professional bike mechanic” territory.

I’ll go one step farther than that. Not only should you probably contact your local bike mechanic if you think you might need this service, if this isn’t a service your bike mechanic offers you might just want to find yourself a new one that does.

The post Saving Face, or How I Learned To Stop Worrying and Love My Brakes first appeared on Slowtwitch News.

Aerolab is ready to take its pull at the front. Will this be the brand that finally breaks away?

Aerolab asserts that its newly released technology will allow almost-real-time measurement of aerodynamic drag, rolling resistance, and an assortment of other metrics, and will do so in a simple and robust manner that minimizes the time, labor, and expense of previous approaches. The precision of a wind tunnel brought home to your garage. Or, more likely, your local bike fit studio.

While real-time aero data, visible to riders while they’re riding as promised by the Velosense system previewed at Interbike in 2018 is the aero sensor Holy Grail, this appears closer to science fiction than science. The current state of the tech requires a series of test runs to gather data sufficient for robust analysis, subject to post-ride analysis. Aerolab has crafted a business model based on this.

This is not a plug and play system, and some degree of training and expertise is needed to generate a reliable result. Last week Aerolab released a set of training modules for bike fitters to educate them on the system.

Pricing to fitters is based on a 12, 6, or 3 month lease, costing $4985, $2995 or $1895 respectively.

Because of the expense of the system, the training required, and the need to familiarize oneself with the software, this is likely to be a fitter-driven process, much like the difference between a consumer buying his own wind tunnel time versus contacting with a bike fitter or aerodynamicist familiar with the wind tunnel process.

Aerolab is courting bike fitters, and sees this business class as an ideal purveyor of their technology. Giving fitters the ability to offer aerodynamic testing as a component of bike fit is obviously an attractive proposition, but Aerolab is looking well past this. Its brand managers believe their product can greatly expand the palette of services a fitter provides. “Which is the fastest wheel on the market?” is not a proper question according to Aerolab (if we understand the thinking). “Which is the fastest wheel for me, on the particular bike I own and on which I will race?” is more like it. This is the kind of answer its tech aspires to provide, with the bike fitter as the service provider.

Even more, Aerolab believes it’s technology can answer not just aerodynamic questions – what wheel is faster, what bike position is faster, hands high, hands low, cockpit lower or higher, armrests narrower or wider, which helmet works best for me, personally, etc. – but solve rolling resistance questions, specific not just to the type of tire, but to the wheel it is on, and the specific real-world course conditions it will be used on.

How does all this compare to the other product offerings in this category? According to bike aerodynamicists familiar with the landscape, Garmin – which purchased Alphamantis in 2017 – is not close to releasing a product. "We are continuously researching and innovating and can’t comment on any future or unannounced products or plans," is Garmin's statement when asked about Alphamantis. If Velosense has a product, we don't know about it.

The Notio sensor that we profiled back in 2017 is available on the market, but despite the attractive price point of $599, doesn’t appear to have generated a lot of momentum in the marketplace.

One source commented that both SwissSide and Aerolab have the ability to collect and process yaw data, which the other aero sensor products (according to the source) do not. To the best of our knowledge, SwissSide is focused on using their proprietary technology in a product development and manufacturing consultancy role rather than a consumer facing one.

One user of the tech, formally a user of Alphamantis, is encouraged, telling us that Aerolab has finally gotten to a place where this tech is usable and reliable. Emphasis on “just.” If you’d have asked him about Aerolab six months ago, he may have said the tech is not quite ready. Aerolab technology is being used, right now, with confidence according to those with whom we’ve spoken, both for new bikes that are in development, and for pro cyclists and triathletes who want to dial in their positions and equipment. More to come…

The post Aerolab Brings the Wind Tunnel To You first appeared on Slowtwitch News.

It turns out that this system is manufactured for Lezyne by F3 cycling. While the version of this mount sold by Lezyne is only compatible with the Lezyne family of head units, there is good news for the Wahoo/Garmin/Karoo users out there; all the same features (and more) are available to you, too, in the form of the – ahem – F3 FormMount.

Retailing at $59.99, the FormMount is a carbon composite structure that attaches to your stem via the faceplate bolts. It comes complete with Garmin and Wahoo “puck-style” inserts, 2 sets of stainless steel M5 bolts, black aluminum spacers that fit over the shaft of the bolts, a gray spacer/accent stripe, and all the bits and bobs necessary to put the whole thing together, including a stiffening brace to help with alignment of the mount and increase stability when mounting heavy computer/light/camera setups.

The manufacturer’s claimed weight is 24.89g (sans brace) and my sample was pretty much dead on target.

F3 offers a range of accessories for the mount, including a GoPro style camera/light mount, extra short arms for use with smaller computers, accent spacers in a range of colors and titanium bolts in both raw titanium and black finishes in 35mm and 40mm lengths. Extra spacers come included with those screws.

The FormMount attaches to your bike by way of the stem mounting bolts, which are replaced with extra long versions that now secure both your bars and your mount to the stem.

Two hockey stick shaped arms connect to those bolts, with small aluminum spacers ensuring that they correctly interface with the stem. The mount itself is comprised of three parts. The top part accepts a puck computer interface that can be swapped out for different brand requirements or for replacement due to wear. The middle part is a spacer, and the bottom part has tracks formed in it to accept the arms of the mount. The whole sandwich clamps together to fasten things in place via 2 small screws using a 2mm hex wrench. The mounting pucks are held in place by a single screw (for Wahoo) and 2 screws (Garmin), these also fastening by way of a 2mm wrench.

The arms of the mount swivel, and the mount will thus adjust to fit most 4-bolt faceplate stems with M5 bolts that have parallel axes and bolt centers from 16mm to 41mm. This isn’t every stem on the market, but it’s a lot of them!

Not only do the arms of the mount swivel, but the mount slides fore and aft on them so you can adjust the length of the mount to accommodate different size head units, and snug whatever unit you use right in tight to the front of the stem regardless of whether you’re running a large head unit,

or a small one.

That’s still the long arms on the mount with the bolt. You can get things even tighter with the optional short arms.

There are detents molded into the tracks to help keep the assembly square and parallel through the range of adjustment. That’s a nice touch.

There are a lot of nice touches to this system. Take the light/camera mount accessory, for example. Like the rest of the mount body, it’s made of carbon composite. F3 don’t make the mistake of trying to cut threads into this stuff for the mounting bolt, or of bonding in a threaded insert. Instead, they use an external, easily replaceable acorn nut. If you’ve stripped out a GoPro style mount trying to keep a light to stay pointed in the right direction on another mount (and I sure have) you’ll appreciate the detail. There’s even a stop molded in on the nutward side to keep said nut from spinning during installation.

There’s a lot more going on here than with your typical “bolt it on to the handlebar” type computer/light mount, and the result is a mount that offers tremendous versatility and adaptability. Are you looking to mount a small, race-oriented head unit like a Wahoo Bolt close in to the stem to minimize the profile of your front end? Game on. Running a big ‘ole Roam or Garmin 1030 and a GoPro on the front of your gravel bike? Just add the optional Light/Camera mount and maybe the bridge tool, and you’re covered.

This “one ring to rule them all” aspect of the FormMount is fairly unique in the world of computer mounts, but for many applications the use of the stem bolts to secure the mount is an even bigger highlight. Finding the real estate to add a computer mount to an aero profile bar, or weaving your way through shift housing, hydraulic hoses, and remote shift switches trying to get a computer mount in place are things you just don’t have to worry about anymore. Everything mounts with zero impact on your bar space.

It winds up looking pretty darn clean from the front as well.

You don’t get all these pluses without a downside, though. There’s a fair bit of added complexity to this system compared to most of the mounts on the market. There are lots of moving parts, and some really tiny screws holding everything together. Having said that, I have put some fairly significant miles in using the FormMount, all of them with a full size head unit and a camera or light on board and none using the stiffening brace. Most of these miles have been on my gravel bike, and a lot of those have included some pretty burly terrain. In the time I have been testing the FormMount, I have broken two other computer mounts that were in for testing, plus the frame of the bike I was doing most of the testing on. The FormMount has survived all of this unscathed; nothing loose, no wobbles, no problems. I do find myself checking those tiny little screws on a regular basis, though, just to be sure.

My second area of concern is even more speculative. When you use this mount, you’re hanging a bunch of stuff off a fairly long lever that’s secured by the bolts that hold your bars in place. What happens if you whack the heck out of that lever arm, say – for example – in the process of crashing your bike? It seems to me that just might be the kind of thing that could turn a fairly innocuous incident into a call home for a ride. Hopefully you’re somewhere you can get a ride if this happens! I’ve been keeping a couple of extra stem bolts in my seat bag, just in case.

Those (speculative!) caveats aside, I really have nothing but good things to say about this product. It’s light, it’s incredibly adjustable, it looks cool in a Terry Gilliam’s Brazil kind of way, and it’s the mount I’m using to hold my own computer on my own bike these days.

The post F3 FormMount: One Mount to Rule Them All? first appeared on Slowtwitch News.

First up: the Park Tool PP-1 piston press.

Park is selling version 1.2 of this now, but I haven’t got the new version, so I can’t talk about it. What I can talk about is how long I put off buying a piston press, figuring that a plastic tire lever was good enough.

It wasn’t.

You simply push this thing in between your brake pads, and it spreads them apart. Evenly. No wiggling back and forth, as you’re forced to do with a makeshift solution like a tire lever. No scarring of the pads, which is absolutely going to happen at some point if you just use a screwdriver.

If you work on disc brakes, you should have a piston press. This is a good one.

Now that you have the right tool to push your pads into position, it’s time for the Birzman Clam.

This is a wonderfully simple piece of kit. It’s literally just a folded sheet of aluminum. To use it, first press the pistons to their fully open position using the piston press we just talked about. After you’re done that, loosen the bolts that hold your brake caliper to your bike frame and place the clam on top of the brake rotor.

Rotate the wheel until the rotor/clam sandwich is between the brake pads, inside the brake caliper. Now, squeeze the brake lever, and tighten the fixing bolts back up while continuing to apply pressure to the brake lever. Once you’ve snugged up those bolts, simply rotate the caliper forward, remove the clam, and you should be good to go.

Good to go! That is, if your brake mounts are faced correctly, your pistons are retracting evenly, your system doesn’t need to be bled, and your disc rotor is true. It’s just that simple.

Rarely. It’s rarely just that simple.

In reality, your brakes may well need to be bled, your pistons might not be retracting properly, your rotors probably aren’t true, and your mounts do need to be faced.

We won’t cover all of those today, but the Abbey Bike Tools Stu Stick will at least help you with the bent rotors.

Once again, this is a simple yet elegant tool. It’s a 4mm x 25mm bar of anodized aluminum with a slot (and a bottle opener) machined into it. Newer versions of the tool have two slots, but yes; I own an older, first generation example.

How does thing work? Just spin the wheel while it’s still on your bike, and observe the brake rotor/brake pad interface.

If the rotor wobbles significantly from side to side, you can now fix that. Slide the slot in the tool over the part of the rotor that is wobbling, and use it as a lever to crank the rotor over to the side opposite the wobble. Be gentle. Repeat as necessary until you have a rotor that is flat/true enough to allow you to depress the brake lever without the pads making intermittent contact with the rotor for the majority of their travel.

Try to avoid the temptation to make the rotor perfectly flat. That way lies madness. You’re just looking to make it true enough that it doesn’t “pulse” as you apply the brakes.

Lots of companies are making a tool like this these days, but Abbey was one of the first – if not the first to make a lightweight aluminum version. You will find these in a lot of traveling race mechanic’s tool kits (including mine) for just that reason. Bonus points for being named after Stu Thorne, for being only $22, and for including a bottle opener.

Last item today is from Prometheus lights.

This is the Beta flashlight and Flex Arm combo. Combining a AAA flashlight with an articulated mount that terminates in a magnet, this gives you a portable light source that will mount to any magnetically attractive surface. My eyesight isn’t what it used to be, and I find myself reaching for this more and more these days. It readily attaches itself to any steel bike frame, or steel part on a non-ferrous frame. When I’m working in an area without a convenient piece of metal to attach the unit to, I simply wrap this Magnogrip wristband around the frame and stick the light to that.

It turns out that it’s a heck of a lot easier to work on something like disc brakes when you can actually see what you’re doing.

The post The Wrenegade Wrench: Disc Brake Bits first appeared on Slowtwitch News.

This is the first installment in a new column devoted to working on bikes. As time goes by, we’re going to talk about tools, parts, and processes, and share tips and tricks that make working on bikes a little bit easier, a little bit less mysterious, and – hopefully – a lot less frustrating. Future installments will include solutions to common problems, favorite tricks from some of our favorite mechanics, tool tips and reviews and more, always with an eye towards the world of the DIY Slowtwitch home mechanic.

We’re kicking things off with full-tilt DIY, the Wrenegade Wrench homebrew cable guide kit.

If you work on your own bikes it’s pretty much inevitable that you have – or will, eventually – be forced to reckon with the task of running cables/housing/hoses through the labyrinthian interior of a bicycle frame.

There are a fair number of products available on the market to help make this task at least a wee bit easier. Over the years, I’ve used most of them, and some of them are pretty darn good. Slowman wrote a piece on internal cable management a while back that featured the de facto industry standard solution from Park Tools.

The Park Tools kit is the standard for a reason; it’s a really good system. For those who haven’t used one, the basic concept is fairly simple: a magnet is attached to a long line, and the other end of the line has something on it that connects to whatever you need to route through your bike frame. You stick the magnet on the end of the line into the entry port on the frame, and you pull it through the frame with another magnet on the outside of the frame.

Oddly enough, I’ve had a nearly identical puller kit in my tool box for a couple of decades now. It was originally used to pull wiring harness components into place when I was working on hollow body electric guitars, back in my previous life in the luthiery business.

25-30 years or so ago if you wanted something like this you absolutely had to make it yourself. Today, even though you can buy one for 65 bucks or so, there’s still something to be said for a home-brew kit that you can tailor to your own particular needs.

The homebrew alternative is also pretty darn inexpensive. I put my kit together from things I had lying around the shop and about $20 worth of bits ordered from Amazon. If you had to purchase everything needed to put these together, you’d probably be looking at around fifty bucks, but you’d also wind up with a lifetime’s supply of kits for yourself and a couple of friends, plus some extra bits that are nice to have around the shop anyways.

Here's the parts list:

– Cylinder magnets, 4 (or 3)mm x 10 mm.
The standard nominal OD of bicycle brake cable housing is 5mm,
and once assembled a 4mm magnet will mic out at around
4.37mm. That’s a wee bit larger than the 4.25 that I just measured
a nominally 4mm shift housing at. What this means is that 4mm
magnets will work for the vast majority of applications, but you
might want to use 3mm diameter magnets just to be sure.
– Loop-end floating fly fishing line
I’m using fly fishing line for these because, well, it works great.
Very strong, very light and thin, and glue sticks to it. It’s worth
spending the $8-10 it costs to get some if you don’t happen to
have some lying around.
– 1/8” OD x 1/16 ID latex tubing
– Heat shrink tubing in various sizes
– A hydraulic hose barb
– Medium or thick cyanoacrylate adhesive (superglue, not the water
thin kind)

Now let’s look at how these go together.

Step One
Cut your fishing line to length. You’ll want something that’s long enough to go the distance of the internal routing channel in any frame that you may conceivably work on. The penalty for going too long is pretty much nonexistent, so add a foot or two to whatever you think is reasonable. 250cm or so is a pretty safe bet.

Step Two
Thread some heat shrink tubing over the line. Don’t forget to do this before you get everything glued together, or you’ll be starting over! You’re going to want to use two sections of tubing, one that is just big enough to slide over your magnet (or whatever is going to be on the other end of the line), and one that is just barely big enough to slide over the line itself.

Step Three
Tie a knot in the end of the line. This doesn’t have to be anything fancy, you’re just looking to increase the surface area of the line at the point that it makes contact with the magnet.

Step 4
Glue the magnet to the line.

I’m using medium thickness super glue for this, but there are other adhesives that will work fine. You may want to use something to hold everything together while it dries.

Step Five
Slide the heat shrink tubing up so that the smaller piece is right against the knot in the line, and the larger piece is lapped over the magnet, then apply heat.

That takes care of the magnet end. On the other end of the line, you’re going to want/need a couple of different things.

For the simplest variant, I just use the loop that came formed into the fishing line. This works pretty darn well with, for example, DI2 connectors.

This works surprisingly well with brake/derailleur housing and brake tubing as well. Just add a little bit of scotch tape.

It’s more than solid enough to pull through a frame if the guides aren’t super tight.

Another variant adds a latex tube at the end of the line.

Once again, slide your heat shrink tubing onto the line, but then follow up by sliding about an inch of latex tube on as well. Knot the line after it has been slid through the tube, then pull the knot back through until it’s just about to pop out the other end. Drip some glue down over the end that the line comes out of, let dry, and finish up by repeating the heat shrink process described earlier.

I’m using a 1/8” OD x 1/16” ID tube, and it’s pretty multi-functional. It’ll slide over a brake cable (it’s a wee bit too big for a derailleur cable, but a wrap of scotch tape over the cable fixes that) over the contact of an eTap blip connector, and it’s just the right size to slip inside a DI2 connector and over the male contact inside. Pretty slick.

I do typically add a wrap of tape over the junction between the tube and whatever it’s attached to before I pull it through the bike, just in case. If you want to use a larger ID tube that will fit over the DI2 connector have at it, but this has been working pretty well for me.

If you’ve used the commercially available version of this setup – or read the piece I linked to above – you know that the tubes on these things tend to break down over time. It’s worth making the tube a wee bit long so you can cut it down as it deteriorates. It’s no big deal to replace one when it does, but these things do tend to happen at the worst possible time, generally when you really, really need to get the darn cables in NOW!

The third thing I would recommend putting on the end of one of these is a hydraulic hose barb.

It’s pretty obvious why you might want this, eh? To pull hydraulic hose through! That’s not all, though. This will work really well with both derailleur and brake housing.

Same basic build process as we used for the latex tube. Pull the knot back through the barb, drip glue in, heat shrink over the top, voila!

To use, just push the barb into the hose/housing far enough to get a grip, but not so far that it’s going to be a pain to remove. The outer diameter of this winds up being pretty much identical to your housing/tubing, so it’ll fit through just about any molded-in guides you might come across. You can make this OD even smaller by grinding down the flange in the barb a wee bit (but leave some of it in place to ease removal from whatever you’re sticking it in).

Oh! One last thing! You’re going to need something to pull these through your frame. To be honest, I mostly just use a bare magnet, but I also glued another magnet on to the end of section of brake hose.

This winds up being pretty useful to reach inside the frame to scoop up the end of the line when it approaches the “out” of a frame.

So maybe put one together if you’ve got magnets left over.

The post The Wrenegade Wrench Series: Homebrew Cable Guide Kit first appeared on Slowtwitch News.

My answer to that last question has typically been, “If you’re doing any of the rides I’m doing (and you’re not getting paid to ride your bike, you’re going to want a 1/1 small chainring/biggest cog." With a “standard” Shimano compact double crankset, that means running an 11/34 on the rear to match the 50 (or 48/46) x 34 on the front.

Conveniently, that’s the biggest cog Shimano offers on their cogsets that are designed to run with a double chainring road/gravel setup. If you want anything with a bit more climbing “oomph” you’re jumping up to at least a 40t cog and running a single ring setup, or you’re running a GRX crank with smaller chainrings and gaming your gear ratio that way. Or, well, you’re doing something tricky with a derailleur hanger extension and/or component combinations that aren’t exactly manufacturer recommended.

But what if we – in the words of Nigel Tufnel – “need that extra push over the cliff” with a standard double chainring setup? Enter the ZTTO SLR2 cassette. Yes, this one goes to 11. But it also goes to 36.

As I wrote earlier, if you’re doing the gravel rides I’m doing these days, you really do want – probably need – that 1/1 ratio, but being able to go one gear better than that is… well, it’s better. A tiny bit more spin on the long grinds and a wee bit more torque on the steep technical stuff is just enough to make my rides a bit more fun when I’m having fun, and a touch faster when I’m trying to go fast.

Tooth counts for this cassette are: 11/13/15/17/19/21/23/25/28/32/36.
Comparatively, the Shimano 11/34: 11/13/15/17/19/21/23/25/27/30/34

You’ll notice they didn’t just pop a 36 on top of a 34 cassette cluster, but they also didn’t mess with the spacing on the smaller cogs. They bumped the tooth count up on the three biggest cogs. I ride a double chainring setup on my gravel bike almost entirely due to the amount of pavement I still find myself on, and too much mucking about with the tooth counts on those smaller cogs would mess with the tight ratio changes on the for going fast on the road. But up in the higher range of the cassette, I’m a lot less concerned about this. Frankly, I think they nailed the ratios on this. When I first bought this cassette I was just looking for a little bit of help on long, grinding uphills. While out riding this past weekend, I found myself on some singletrack terrain that I just flat-out would have been walking had I been on that 11/34. It wasn’t just the 36 that kept me on the bike, it was the 32 as well. Bouncing between those two gears as I monster trucked over stairstep roots and rocks put me in “MTB with drop bars” mode in a way that just hadn’t happened for me before with a road style 50/34 on the front. It turns out there is a little bit of magic that happens when you get around/under that 1/1 ratio riding really technical stuff off road.

Somehow, I had forgotten about that.

Before I get even more hyperbolic, suffice to say that 32/36 on the low end of the cassette is pretty great. I’m sold. Unfortunately, Shimano doesn’t currently make anything bigger than a 34 in a road/gravel style cassette, which means we’re stuck looking for something like this from a 3rd party manufacturer. Aren’t aftermarket/off-brand cassettes all just junk?

Historically my answer to that question has been a pretty unqualified “yes”. Manufacturing something like a cassette just isn’t easy, and up until fairly recently, there were a bunch of patent pitfalls in the way of the third-party efforts. Based on the few weeks I have put in on this cassette, though, times seem to have changed. It really is beautifully made:

…even if you ignore the rainbow anodization (and yes, you can get it in a plain silver color).

The six largest cogs are machined out of a big block of aluminum, and the machining includes a full complement of ramps and tooth shaping to coax your chain from one cog to another. The five smaller cogs are steel, three of them attached to the aluminum structure the six aluminum cogs are machined out of.

The two smallest cogs are individual units that slide on to the cassette body in traditional fashion.

How does this thing shift? Pretty darn well. Shimano doesn’t recommend putting anything larger than a 34 on with the setup I’m running, so there’s a wee bit of caveat emptor here. Having said that, there isn’t a dramatic difference in shift quality between this and the 11/34 Ultegra cassette that was on my bike previously. That’s a compliment. It’s maybe a little bit slower to respond on the bigger cogs than the Shimano unit, but I haven’t had a single missed shift. You can tell that you’re shifting across bigger jumps on the larger cogs but, well… you are.

My main gravel ride is set up with Shimano Ultegra Di2, and I have found that I really like synchro shift for gravel riding. All the shift-logic simplicity of a 1x drivetrain with all the advantages of a 2x, and the right and left shift levers can be set up to do the same thing. Pretty cool. My shift point on the downshift jumps the chain from the 32 to the 25, at more or less the same time it shifts the front from the 50 to the 34.

That’s a pretty demanding gear change, and you can definitely hear – and feel – the “clunk!” as it happens. It does happen, though, and it has reliably happened for me regardless of how much power I’ve been putting through the pedals at the time.

With all that aluminum, you would expect this cassette to be light, and you’d be correct. Mine weighed in at 229g, with the (included) aluminum lockring. That’s 100 grams less than the 11/34 Shimano Ultegra cassette without a lockring.

Aluminum cogsets have a well deserved reputation for wearing out pretty darn quickly, but with a 1000 or so miles in on this one, It’s looking just about the same as when I put it on. I’ve been running a hot-waxed chain, and we’ve been blessed with more or less completely dry conditions this summer, and those definitely combine to minimize wear, but still. So far, so good.

It’s worth noting that this is a native 11-speed cassette. It won’t mount on a 10-speed spaced hub, unlike some of the Shimano 34t freehubs.

Price? At this moment, you can buy one of these in a plain grey color for $53 on the ZTTO page at Aliexpress. The fancy rainbow ano version will set you back $81.12. That compares pretty well to the Shimano Ultegra, which sells for right around $90. You can also find these on Ebay, and via other purveyors on the Interwebs. You may even be able to find the same thing for less dough with a different name on it, but caveat emptor definitely applies here.

When I bought this cassette it was for the single, specific purpose of eking out a slightly lower gear for an event I was signed up for this summer. It probably goes without saying that the event eventually wound up being removed from my calendar. The cassette, though, wound up staying on my bike.

The post The ZTTO SLR2 Cassette: It Goes to 11 (But Also 36) first appeared on Slowtwitch News.

For good and ill, those times are long gone. We now live in an age where bar-top real estate is at a premium, and mounting a front light on your bike can be more than a little bit of a hassle. How a manufacturer addresses this is a big part of what differentiates a good light system from a great one, well above and beyond the obvious illumination and operation aspects of said system.

Lezyne does some things really darn well in this area, and they’re worth talking about in depth.

As shipped in its stock form, the Lezyne 100XL comes with a rather nice variation on the “rubber(ish) strap with holes that stretch over plastic hook-type-things” theme.

As seen in this picture, you can rotate the strap mount so that it wraps around a tube parallel to the axis of the light as well as perpendicular, and any degree of intermediate rotation desired. This comes in pretty handy if you want to do something like mount the light to the underside of an aerobar, or if your handlebar tops aren’t perfectly perpendicular to your stem, as is quite common these days. This is a very useful feature that is not shared by all of its competitors.

Rotational allowance aside, this mounting system is fairly typical of lights at all levels of the price spectrum these days. It works well; it is easy to put on and take off, has enough stretch to fit around most bars that you might want to strap it to, and is quite robust, showing absolutely no signs of wear in the time that I have had it.

Even better, you can simply unscrew it from the back of the light, and replace it with a Go-Pro style mount.

My friends, Go-Pro mounts aren’t just for cameras anymore. I currently have at least one Go-Pro mount on all the bikes I ride, and it’s actually pretty rare that they see a camera. They wind up carrying a light 90 plus percent of the time.

If you’ve read the previous reviews I have written on light systems here at Slowtwitch, you may have noticed that I am a zealous advocate for the adoption of a universal light mounting standard for bikes. It’s more than a little ridiculous that we’re reduced to zip-tying and rubber strapping lights on to our multi-thousand dollar bicycles like an afterthought or an affectation. It’s well past time that bike designers include provisions for light mounting in those designs, and while I think the “standard” that those mount points should adhere to is still open to applicants when it comes to rear lights, I’m going to go out on a limb and suggest that the ballot for front lights has been read, and the winner is the Go-Pro style mount.

Manufacturers, get to it. Start putting these mounts on your stems/bars/bikes, what have you.

While the age of the universal light mount standard may well never come, it’s nice that Lezyne has been thinking about this a fair bit and has partnered with some other smart folks to put together a really darn nice mount for their lights. Or their head units. Or both. Or whatever else you might want to mount to it.

The name of this mount is the Direct X-Lock Mount System.

While Lezyne doesn’t advertise it, the subtle logo impression on the side of the unit makes it pretty clear that they outsourced this project to the people at F3 Cycling.

F3 offer a very similar product for $20 more than the $39.99 Lezyne charges, and the F3 version doesn’t include all the accessories that you get gratis with the Lezyne version.

The F3 version does swap compatibility with Lezyne computer mounts for compatibility with Garmin and Wahoo style ¼ turn mounts, and that’s probably worth the bump in price for some folks. This is very much in keeping with the general theme of the Lezyne head units, which I think can be summarized as “all the cool features, a fair bit less coin” oftentimes conjoined with “…but may not do all those cool things quite the way you’re used to."

If you’re looking to mount a Lezyne head unit, or a Lezyne head unit and light, or a light and a Go-Pro (yes, you can configure this with two Go-Pro style mounts) then I think you’ll be hard pressed to find a better solution, provided you are using a compatible stem, and most stems that use a 4-bolt faceplate will be compatible.

Once installed, this is a clean looking set-up.

And it’s solid: nary a hint of flex nor wobble, even on rowdy gravel terrain. As you can see in the pictures, you don’t lose any bar-top real estate to mounting hardware, and this is particularly handy on bikes that might see aerobars coming on and off, or electronic shift points mounted on the tops.

What you can’t really see in the photos is just how adjustable this light is, as that ability to rotate the mounting point I mentioned earlier carries on in the GoPro style configuration. In contrast here’s the setup I’ve been running on another bike:

…where the computer and light are mounted directly to the aerobars, again via a GoPro style mount. The light mounted in this picture doesn’t share the Lezyne’s ability to rotate around the mount point, and as a result it is always aimed just a tiny bit off-center from where the bars are pointing.

This is a minor annoyance, but it definitely is an annoyance, and I solved the issue by swapping the lights between the two bikes pictured here immediately after the photos were taken.

This is probably a good way to sum up my experience with the mounting options offered by Lezyne. After a few weeks of testing, I’m running the Lezyne light on the non-Lezyne mount because it’s adjustable enough to compensate for the shortcomings of the non-Lezyne mount, and I’m running the non-Lezyne light on the Lezyne mount because it’s shortcomings in adjustability aren’t a problem with the Lezyne mount.

Score 2 for Lezyne.

The post Lezyne Lights Part III, or Who Doesn’t Like a Clean Front-End? first appeared on Slowtwitch News.