Tubeless For Cyclocross – The Complete Saga

A little more than a year ago, I was riding through the local trail system, over rugged MTB terrain, entirely unhindered by the fact that there was a ‘cross bike between my legs. I was railing loose gravel corners, and clawing my way up steep, bony trails, enjoying plush compliance and plier-like grip. I was plowing over rocks, roots, through streambeds, etc., all without pinching or having my seat punch my backside up into the air. I was thinking “this is amazing—it is totally going to change the CX world”.

This is the real tragedy of tubeless cyclocross set-ups: when they work, they’re awesome. The problem is that for racers, they don’t reliably work. There are plenty of instructions out there, and lots of positive stories. Unfortunately, I can’t say this is one of them.

From the Beginning

In 2009, I had a pretty miserable run of it on clinchers. Some bad luck, some bad riding habits, and some unwillingness to suffer a jarring, high-psi ride left me as a DNF in one out of every five events I started. So after flatting out of a grassy practice race at the beginning of 2010, and being unable to afford the expense and hassle of tubulars at that time, I decided to give tubeless tires a shot.

I ordered a Stan’s Conversion Kit for the Easton Ascent II wheelset I had from road racing. It was with much trepidation that I drilled out the inner wall valve hole to 7/16″, but the wheelset (running standard road clinchers) held up just fine through the 2011 road reason—impressive considering its age, let alone the enlarged hole. I will say that the rims are on the “tighter” side of 700c, and I couldn’t mount any tires with the conversion kit and the factory rim strip in place. Even with just the Stan’s rubber strip on the bare metal, it was a tight squeeze.

The tires I chose—Hutchinson’s tubeless-ready Bulldog CX’s—only made it on to the rim with a tremendous amount of effort and a few broken Pedro’s levers. Once I’d wrestled the tires on, I’d expected my lack of compressor would be a liability, but the front tire, with some soap, a half-cup of Stan’s, and a floor pump, actually inflated pretty handily with the valve core removed (others have had similar experiences). Once I’d set the bead, inflating with the valve core in was no problem.

The rear proved more difficult. No matter how much Stan’s/suds I used, air stubbornly kept slipping out faster than I could put it in. Even at the local garage, the (max 85psi) air pump couldn’t keep up with the leaking. Only after I gave up and removed the tire did I notice that the left-side bead had snapped, leaving a flaccid indentation that refused to hold the rim, even when mounted with a tube.

Eff This, I Wanna Ride

The thing is, a freshly-mounted tire really makes you want to ride. Especially when, pry as you might, you can’t get it to slurp even the tiniest bit of air as you manually wrench it back and forth at 29psi. So I grabbed an older Michelin Mud2, a cup of Stan’s, and another bucket of suds, and within a few minutes, had a second tubeless tire mounted—to the Reservoir!

That puts us back at the beginning of this story—tear-assing like a boss through trails that I had no business riding on a ‘cross bike, to the point that the hard bottom-outs were beginning to bang-up my a-little-light-for-this rims. Even on the faster, more-CX-like sections, the compliant ride and tear-the-grass-out cornering grip were just amazing; everything I’d wanted but never gotten on the clinchers I’d been suffering with for years.

There was still the matter of the broken bead, of course—I’d purchased through an online retailer and the warranty process was going to take weeks, since I had to send it to them, and they had to send it to Hutchinson, and then the process had to reverse. But the Mud2 seemed to be getting the job done.

Some Cracks in the Armor

After a few more vigorous shred sessions at the Res, I’d only found one situation where I encountered the dreaded burp—remounting. Now, my remounts have never been graceful, and last fall they were particularly bad, but only on the ugliest, most awkward landings—overjumping by seven or eight inches and slamming onto the saddle as much sideways as down—did a small bit of air scoot out of my rear tire. It was, according to my mini-pump, less than 5psi on the first burp, and generally, 2 or 3 were survivable before things got sloppy enough that I needed to re-inflate.

Because of the burp-out issue, I had to run the rear tire at a higher pressure (35+ psi) at last year’s Cycle-Smart International, which kinda defeated the purpose—namely, to pedal, rather than bounce, across a notoriously rooty section at that race. I also found myself reverting to step-‘n-hop mounts to prevent burping, which cost me additional time. While I had no qualms about driving the 30psi front tire through corners, as the grassy, hard-grabbing corners wore on, I definitely felt my rear tire getting floppier—not enough to physically slow me, but certainly enough to sap some confidence.

A day or two before Putney, the sidewall on the several-years-old Michelin Mud2 finally broke, rendering it more or less useless for tubeless. I picked up a Maxxis Raze at the local shop, which turned out to be a mistake. By the time of the B race, most of the course had sticky, hard-packed mud ruts—fairly easy to ride, but they also pulled hard at tire bead on every corner. I went about a lap and a half before totally deflation and tire loss. Not cool.

(The Raze also rolled at Ice Weasels, running with a tube. As a race tire, the Raze sucks.)

A Side-by-Side Test

Warranty hassle rolled inexorably onward with the Hutchinson Bulldog. The online retailer I’d bought through couldn’t get in touch with the company, so I went through a back channel, and finally got the case addressed—though my tire would not be in before the end of the season. So I bought a Michelin Mud2 at the local shop, and restored the tubeless set-up I’d run at Cycle-Smart, without too many issues.

Last year’s Baystate Cyclocross provided some slick conditions and a truly infernal course—great for testing the efficacy of different cross setups. To sweeten the deal, Colin Reuter lent me a pair of FMB tubulars on the second day, so I had something more or less resembling a side-by-side test.

It wasn’t perfect; Colin, being insecure about his baldness, took a swipe at my weight by not letting me run 28psi in his tires, and there was a not-insignificant difference in tire width (31ish on the FMBs and 34 on the Hutchinsons). That said, while I had a pretty dismal showing in both races, the tubeless setup easily matched the bite and cushiness of their $150 European counterparts.

While I doubt I could have dared the 22psi employed by tubular aficionados in the loosest of muck (and I still had to half-ass remounts and deal with the slow-seep from the rear) the results showed that tubeless was closely competitive with more traditional setups, in addition to fixing many of the problems endemic to clincher racing.

Things Fall Apart

As the numerous Stan’s torture videos will tell you, tubeless is great at resealing itself. But at a Waffle ‘Cross ride in Boston a few days after Baystate, I caught a piece of glass that made a relatively normal puncture in my rear tire. I’d seen Stan’s take care of some pretty gnarly things (tree branches, barbed wire) on MTB tires, but for whatever reason, the cut just wouldn’t seal up, leaving me floundering around on a flat tire until some Good Samaritan passed me a tube. While not a race incident, it sure was “deflating” (tee-hee) to see tubeless fail in the very situation where it was touted as invincible.

In the interval between Waffle ‘Cross and Ice Weasels, things really started to wear out. My rear Stan’s rubber strip failed around the valve hole—or more precisely, the valve ripped free of the rest of the strip. I was able to create a usable seal by reinserting a valve stem cut from a flatted tube through the inside of the hole left in the strip, and bolting it against the rim. However, there rest of the conversion strip hardly seemed in better shape, as it had small cuts and deformations due to the spoke holes.

So I set up what the Internet glibly refers to as the “ghetto rimstrip”—essentially, half an innertube split open and laid down inside the rim bed. This would prove to be a bad decision. While it worked reliably on the trails, on the hard packed corners at Ice Weasels, it slowly leaked air on every hard bend. The demise was slower than Putney, and I managed to get to the pit before total failure, but the tube just isn’t thick enough to seal off the tire under racing forces and pressures.

During the winter, Hutchinson finally came through with the warranty tire, and I was like “effing finally”. After all, running a tubeless-ready Hutchinson with an intact Stan’s rim strip had been great on the front tire all season long. I’d never managed to test it against the arguably more tubeless-unfriendly forces on the rear tire, but there was reason for optimism. That was, until the bead snapped (again) during installation.

It might seem a little defeatist to give up on tubeless, having never simultaneously run tubeless-ready tires without a proper conversion strip on both wheels. But the fact is that the only tire that seemed to be able hold air to the forces of for-real cross racing—the Hutchinson Bulldog—broke before I could set it up almost every time.

To their credit, Hutchinson has backed-up their product, sending me replacements and alternative tires, but [SPOILER ALERT], they’ve given up on producing tubeless-ready rubber for 2012 because their solution, the low-flex carbon bead, can’t stand up to the forces of installation across the variety of rim diameters out there.

We Must Never Forget That There Is Hope

My own relatively frustrating experience doesn’t mean I think everyone out there having a blast on tubeless tires is a liar. For shredding trails on a CX bike—which is awesome, by the way—tubeless was never a hassle for me. And if you’re a for-fun racer with clean remounts who doesn’t mind backing off in the corners a bit, I think you could even get away with doing some less crowded (so you can pick a clean line) CX events on a tubeless setup.

I think there’s also something to be said for rim choice. Both Shimano and Stan’s make what I’m told are very legit tubeless rims. Unfortunately, unless you already own them, it means you’d need to go out and buy a new set of wheels, and the ability to re-use an existing road wheelset is one of the major reasons people race ‘cross on clinchers (and thus inevitably look to tubeless because clinchers aren’t competitive).

Shimano and Stan’s also ship these tubeless rims/wheels at a prices well above Williams’ much-heralded entry-level tubular wheelset. If money is a concern, tubulars (mindbogglingly, considering how much most tubular tires cost) remain the cheaper option.

Mavic’s Ksyrium and Ksyrium-like wheels, which are certainly more broadly distributed within the peloton than either Stan’s or Shimano’s tubeless offerings, might also provide some hope. The rims are free of air-leaking, rim-strip-slicing spoke holes, and as a co-developer of the UST standard, you’d think they’d have the most respect for a solid tire-rim interface. While the company has stepped away from an “official” road tubeless wheelset in recent years (because weight weenies ruin everything), I’m not the only one who thinks it might secretly already exist.

A Note On Tubulars

A lot of people seem to think I view tubeless as some sort of evolutionary replacement for tubulars. I don’t. If you don’t mind dealing with tubular setups (or can afford to pay some other bastard to deal with them), I see no reason to ever switch over to tubeless. Tubies are indeed a complicated, outdated, dirty, resource-intesive, brute-force solution, but they have one singlar, massively compelling argument in their favor—they work.

But viewing the state of tubulars on the road, I think the appeal of a tubeless cyclocross wheelset becomes clear. While pro cyclists with pro mechanics and free gear still use tubulars, most broke-ass racers who purchase and maintain their own equipment don’t. While I’ll stop short of saying there’s no difference between a $180 Tufo and a $60 Michelin on the road, I will say that you’re not going to lose a race because the guy next to you had tubulars and you didn’t.

A viable tubeless CX option would make that competitive parity between tubular and non-tubular a reality in cyclocross as well, and that—from the standpoint of both racers and manufactures—should be where the real allure of tubeless cyclocross lies.