Horse for the Course: Focus Cayo Disc for ButterGold

Rain-drenched, dirt-road sportive annihilates disc pads, jams Garmin buttons

It was like a one-night stand, my buddy Zac said of the weekend’s 80-mile dirt sportive in the pouring rain: “Fun at the time, but in the morning I had some regrets.” 


Put on by local cyclocross fanatic Michael Robson, ButterGold is a friends-of-friends event held on backroads around Boulder, Colorado. Robson, a former pro roadie turned pro photographer and purveyor of Butter products, is generally happiest when conditions are the nastiest. During the ButterGold’s seven hours of continuous rain and splattering mud, the Aussie was all grins.

I used the event as an excuse to brutally test the Focus Cayo Evo 4.0 Disc, with a few modifications. The only substantial change was swapping out the stock 25mm Schwalbe Durano clinchers for 27mm Vittoria Pavés. Having spent the last few weeks on 28mm Continental Ultra Sport IIs that ballooned up to 30mm on the BMC Granfondo’s Shimano RX31 wheels, I’d been spoiled by all the cushioning. I also swapped the stock Fizik Arione for an Aliante, put on an SKS mudguard in utterly futile hopes of reducing road spray, and clamped on a Garmin Edge 1000 with a K-Edge to stay on track. (Or perhaps bail out and still find my way home.)

Some pieces of equipment passed the gritty test with flying colours. Others, not so much.

Riding in the rain on dirt roads is fun. cleaning up the next day, not so much…: riding in the rain on dirt roads is fun. cleaning up the next day, not so much…

I hoped the ‘guard would keep the mud off my back and the insulated CamelBak would keep my drink hot. Both quickly failed 

  • The course: ButterGold, an underground 100mi sportive (abbreviated to 80mi for weather) with generous portions of dirt roads; staggered start for 100 friends of friends, with the goal of all coming together during the ride then hammering the final portion
  • The equipment goal: Speed and comfort for a long day. Meaning, a road bike with a racy position (read: no enormous head tube); fat, plush tyres to soak up impacts from rough dirt roads without overly compromising speed on pavement; enough tyre clearance should rain turn the dirt to sloppy mud; an agreeable saddle. Also, reliable GPS to take shortcuts, should they be needed! 
  • The horse: A Focus Cayo Evo 4.0 Disc, with 27mm Vittoria Pavé clinchers replacing stock 25mm Schwalbe Duranos, Fizik Aliante replacing stock Arione, and Shimano Ultegra pedals, Garmin Edge 1000, K-Edge XL Mount, SKS X-Tra-Dry mudguard

For 2015, Focus added its RAT thru-axle technology to its disc road bikes. RAT combines the width and push-through design of a thru-axle with the speed of a quick release. Just flip open the quick release, give a quarter-turn and pull the axle out. The quick-release lever side has a threaded washer for fine tuning. One thing I learned over a few weeks of riding the Focus in the dry is that RAT is similar to road disc bikes with standard quick releases — you have to really clamp the wheels down hard to avoid the wheels being knocked around slightly in the dropouts, resulting in annoying pad rub. “That thing sounds like a swing set,” the same Zac had noted on an earlier sunny-day ride, as my discs chirped annoyingly in rhythm with our climbing. Once the washers were tightened and the hubs clamped down tight, the sounds issues were erased.

In the steady rain — and in particular, steady rain on dirt roads that kicked up grit onto rotors and calipers – the downside of road disc brakes were revealed, and no amount of clamping could remedy the cacophony of resulting noises.

Robson created a novel format for ButterGold 2015: start in three staggered groups with the idea of everyone coming together towards the end, hammer the last few miles back home, then eat, drink and be merry. Love it. 

The focus cayo evo 4.0 disc has plenty of room for fat tires, like these 27mm vittoria pavés i put on: the focus cayo evo 4.0 disc has plenty of room for fat tires, like these 27mm vittoria pavés i put on

Most disc road bikes thus far are endurance bikes, in part because the long wheelbase of the stable bikes readily accommodate rotors and calipers. (The Specialized Tarmac Disc is the notable exception, with a modified wheel that allows a good chainline with short chainstays and the wider rear hub road discs require.) Along with the long wheelbase, endurance bikes typically also bring taller, slacker head tubes and thus more upright positions. In this landscape, the Focus Cayo Evo Disc stands out, with its race-bike front end and more nimble handling. 

Yes, the chainstays are the endurance 415mm length, compared with the Tarmac Disc’s 405mm. But the head tube and thus the front-end fit is nice and low, making this only the second road disc bike besides the Tarmac Disc where I have been able to get my preferred position. Aside from comfort and familiarity, getting low is a handy thing when trying to hold the fast wheels at the end of the day. (Note to self: On dirt roads in the rain, trying to hold the wheels of guys who have raced UCI cyclocross world championships is hubris.)

As with previous Cayos I’ve long-term tested, the Cayo Evo Disc has a comfortable lay-up. It’s not insanely stiff laterally like some race bikes, but still lively enough under acceleration. 

The Cayo Evo Disc comes in a variety of configurations. This test bike, the 4.0, has SRAM Rival 22 with hydraulic calipers and 160mm rotors. I’m a fan of the big SRAM Hydro R hoods; planted on the bar, the wide hood creates a comfortable shelf, and the tall silo that houses the reservoir is great for gripping with elbows bent. I’m not, however, a fan of the flared-out Concept EX handlebar Focus specs here. The centre-to-centre width is 39cm at the hoods, and a whopping 47cm at the ends of the drops. This wide-elbow style is somewhat popular for gravel bikes where the cockpit is way up high almost like a mountain bike; on a road bike with a short head tube, it’s just weird. It also tilts the levers.

I couldn’t find fault with the DT Swiss R24 Spline wheels. Using Focus’ RAT axles front and rear and a 17mm internal-width rim, the DTs took the day’s abuse and others without a hitch. Some, like my colleague James, might take issue with that 17mm being on the narrower side of modern rims. But it made for true measurement on the two sets of tyres I used. The hubs were slightly crunchy at day’s end, but not too bad. 

The stock Schwalbe 25mm Duranos are decent clinchers, but ride as their name suggests with more of an emphasis on durability than buttery cushion. With ButterGold being distinctly not buttery smooth by nature, despite the name, the Vittoria Pavés at a low PSI were in order. Although flats are often as much about luck as tyre composition, I had grace on my side despite the lousy road surface.

You’ve probably heard a lot of talk about needing tubeless to run low pressures, and that certainly is an option. I’ve had great luck with tubeless Hutchinson Sector 28s. In fact, the last time I did a big dirt sportive with Robson, he and I were seemingly the only ones not to flat — and both of us had Sector 28s with sealant. In any event, running wide clinchers can certainly be done at lower pressures too. I set mine at 60psi. (I weigh 185lb/84kg, and the bike is about 20lb/9kg.) Let me tell you, Vittoria knows its way around tyres. The Pavé is a beautiful articulation of a clincher, and towards the end of the day I was smashing into all manner of water-filled potholes without the least bit of finesse, but without a flat, either.

A number of us had disc bikes, which were as susceptible to grit as standard calipers, but noisier. by the end of the day, the squealing and squawking was comical: a number of us had disc bikes, which were as susceptible to grit as standard calipers, but noisier. by the end of the day, the squealing and squawking was comical

As the pace was casual for most of the day, we had plenty of time to swap notes on our bikes. Among the standard rim-brake road bikes, a few men and women rode ’cross bikes and a few of us had disc road bikes. Within a few miles we were splashing down dirt roads. With so much grit spraying all over everything, braking for the odd stop sign was pretty comical. Aluminium rim brakes scratched, carbon rim brakes were underwhelming and the disc brakes squealed like dying seals.

As we were effectively riding an enduro ’cross course, the cyclocross calipers seemed the best suited tools for the task, with a wide-splayed stance staying clear of the rims. The short clearance of the discs and calipers increasingly became a noisy issue. In the first few hours, as the grit-infested pads dragged and hissed on the rotors, giving the brake levers a short squeeze would somewhat clear the build-up and temporarily silence the brakes. In the final hour or two, after barrelling down muddy road after muddy road, the hissing disc brakes on my bike and others were just an inescapable part of the auditory experience. 

For the record, I am not anti-disc. You likely drive a car, and you probably ride mountain bikes. Discs work pretty darn well. But being an old roadie, I definitely appreciate being able to reach down and quickly adjust pad contact with a barrel adjuster or even the quick release on a rim caliper. I’ve done this when a wheel goes a bit out of true after an impact, or when I get it in my head that the brakes are rubbing. I’ve seen riders like Alberto Contador do this on climbs, then close them down for descents. On road discs, your pad-contact width is what it is.

By the end of the day, the brakes were totally shot. The pads were completely worn off on three of the four backing plates — worn to the point that the metal backing was worn thin and the springs that used to hold the pads off the rotors were ground off, too. As you might expect, the noise was just horrible. Metal on metal with wet road grit in between. Stopping was the worst, but even just rolling along was noisy. After the ride, a good spin of the front wheel with the hand resulted in about 1.5 rotations before it stopped. There was nothing to do during the ride but quite literally grind it out.

The pads were completely worn off on three backing plates. and even the surface of the backing plates and parts of the springs were ground off:

My friend Johs was also on a disc bike. At day’s end, he had a similar picture — but with only three backing plates!

Similarly, the buttons on the Garmin Edge 1000 were completely jammed. The touchscreen worked fine throughout the day, even with thick Capo neoprene gloves. But enough of the fine road grit managed to work itself under the buttons that they could no longer depress. Alas, I coudn’t stop the ride and the navel-gazing Strava file was lost.

I tried blasting the buttons with air and water – which worked for Robson – to no effect. So I dismantled the thing with tiny T5 and T6 wrenches. Once the sand was cleared out, the thing was good as new. Two solutions for next time: the US$15 Edge 1000 condom Garmin sells, or the garden-variety Ziploc bag my friend Zac used. 

The press-fit bottom bracket was also in dire need of a cleaning and regreasing. The shifting cables, thanks to internal routing, seemed to have survived relatively unscathed. The clothing for the laundry, well, we won’t talk about that.

All in all, it was a heck of a fun day. The next morning, as Zac said, did bring some regrets, as we all had to face the music of dealing with thrashed bikes and clothing. Will I be back out there again next year? You better believe it.

Taking apart a garmin edge isn’t too complicated. but there are a number of tiny parts: taking apart a garmin edge isn’t too complicated. but there are a number of tiny parts

Ever wondered what your Garmin looks like on the inside?