The Fall of Discs: What we’ve learned about ’cross disc brakes

Disc brakes made a lot of progress in cyclocross in 2012, and have a long way to go for widespread adoption. Photo: Wil Matthews | www. wilmatthewsphoto.comEditor’s Note: Disc brakes are here for cyclocross in a big way. Nearly every manufacturer is offering at least one disc-ready frame and many of the sport’s heavyweights are adopting the technology for 2012-13. We’ve been proponents of disc technology for ’cross for years and over the coming weeks, contributor Michael Robson will explore the burgeoning arena of ‘cross-specific disc brakes, from the new gear to tips on getting your disc set-up dialed.

As the cyclocross season draws to an end and it’s time to sum up our Fall of Discs series, there are some salient points and observations to be made. There’s no doubt discs in ‘cross are here to stay and here in the U.S. we are leading the charge, but the progression has been slow due to a standoff between riders not wanting to adopt the technology until there’s more equipment on the market and the industry not making equipment until consumers are ready to buy. Even so, this season has seen some modest but significant advancement. Here’s a quick rundown of what we’ve learned and what I think might be in store for next cyclocross season.

Change of focus

When braking was on the rim that area was the focus of our attention. Rims needed to be true, cantilevers needed to be dialed and there was a voodoo art to getting straddle cables just right.

Now the action is all down by the hubs. Rotors should be clean, bedded, true, and shimmed out so each of a rider’s wheels is quickly interchangeable. Calipers need to be adjusted and have appropriate pads installed. Light rotors are great for racing but more susceptible to heat and heavy rotors are, well, heavy. There’s a fair bit to know, but the good news is that most of the knowledge base transfers directly from mountain biking.

Watch your fingers

I was working on a disc bike last summer and I let my right pinky stray a little to close to a spinning rotor. I barely noticed when the end of my finger was neatly chopped off right through the nail due to the surgical precision of the slice, but I felt it in the morning. Lesson learned.

Make it up as you go along

The expense involved with making the switch to discs can be quite a roadblock for some, so riders need to get creative. Frames need to be purchased new, but drivetrain and components can be transferred over from old bikes and re-used.

Building up a quiver of wheels doesn’t have to break the bank. Spare mountain bike hubs can be rebuilt with tubular rims or riders can just repurpose mountain bike wheels for reliable tubeless setups. I saw all manner of adapted wheelsets this season and even took to building some experimental sets. There are no rules here; just do what you can with what you have.

There was steady improvement

From hydraulic adapters to better cable-actuated calipers, brakes improved markedly as 2013 approached. Shimano, Avid (owned by SRAM), Hayes, and TRP introduced lighter calipers with better performance and several of the hydraulic converter options like TRP Parabox proved to be quite competitive, too.

Discs changed the way we ride

Only a little bit, but it is noticeable. To an extent in ‘cross you can only brake as hard as your tires can tolerate, but I found myself braking later into corners, safe in the knowledge that something would actually happen. I even incorporated little moto tricks like feathering the rear brake to pull the bike into corners.

The sensitivity and modulation aspects open up a whole new world of bike handling. I was in the unique position of swapping between a disc and a cantilever-equipped bike in one race this season and when measured side-by-side, lap-by-lap, the difference was pretty amazing. The disc bike felt heavier and was more work to spin up, but had fantastic brakes. The canti’ bike was light, fast, and didn’t stop worth a damn. Once the disc bikes are as light as the current canti’ rigs, it will truly be game on, and it’s close already.

U.S. Nationals was a revelation

Disc brakes had their first real high-profile challenge in the soupy conditions in Verona, Wisconsin. Certain conditions creating a specific consistency of watery mud wreaked havoc with disc brakes. Brakes needed to be adjusted every lap and some riders blew completely through their pads before the end of the race. The backlash and I-told-you-so were deafening. Chronic pad wear turned out to be the Achilles heel of discs; we’d seen it in mountain biking and knew the problem existed, but this issue was cast into sharp relief as the snow melted and the Verona course loosened up.

I carelessly voiced my unmitigated frustrations to Lennard Zinn and he interpreted my tirade as a defection back to cantilevers, but nothing could be further from the truth. I still stand firmly in the disc-brake camp, but as with everything, they are fallible. Manufacturers will get to work on ’cross-specific pad construction (SRAM already has) and there will be another performance jump.

For the record, I have ripped through cantilever pads and shredded the brake tracks of a pair of Zipp 303s in similar conditions. At least with discs all the wear points are cheap and replaceable.

Euros declined to ride discs

It could be tradition, it could be a weight issue, but one thing is for sure: the conditions seen in Verona at nationals are pretty normal in Belgium. They race in runny, disc pad destroying mud all the time. Maybe it’s an equipment issue. The Belgian team (including women, juniors, and espoirs) arrived in Louisville for worlds with something approaching 300 pairs of wheels, some of them Shimano workhorse hoops like C24 and C35 that might be several years old. It would be a huge undertaking to replace all those wheels, not to mention frames and componentry. I know the European riders have been testing and experimenting with discs. Zdenek Stybar raced a Specialized Crux disc a few times this season. My guess is we’ll be seeing more discs on the other side of the puddle next season.

It’s going to get better, a lot better

Next cyclocross season will probably see the greatest leap forward so far. SRAM has production hydraulics nearly ready to go and I would find it very hard to believe that Shimano doesn’t. I suspect by late summer we’ll be seeing some pretty amazing new disc equipment appearing on the market. There will almost certainly be more and better wheels to choose from and based on the fact that earlier this season I built up a set of disc hoops that are 1180 grams and bombproof (more on those later), they will be light enough to catch the eye of the most ardent weight weenie. Frames will get lighter, as will components — late last year I got my Moots PsychloX disc rig to just under 17 pounds, within a quarter-pound of its cantilever sister.

Final word

Bikes are going to get lighter and faster and the brakes will be awesome. I can’t wait.