There are quite a few resources on the web if you want to try tubeless for cyclocross. You can read a good article at Cyclocross Magazine, an article by local racer and tubeless evangelist Michael Robson in Velonews, and don’t forget the Stan’s NoTubes Forum. The primary benefits are less puncture risk due to sealant, less pinch flatting risk without a tube, and better ride quality since there is less material between you and the course.
You’ll quickly learn that if you’re converting a wheelset to use tubeless tires, or trying to use tires designed for tubes, the wheel and tire combination must work together. In this post I will detail my tubeless experience, and let you know a combination I know to work very well.
My new bike came with American Classic Hurricane wheels, A pretty standard 1600 gram, 32 spoke non-aero road wheelset. The only exception is the wider rim profile, at 22m which is a few mm wider than most road wheels. American Classic says this gives the tire a fatter shape for more cornering grip. I can surely say the tires run wider, since my 34mm Hutchinson Piranha tires measured at a monster 37.5mm which is well beyond the new UCI limit of 33mm.
The bike also came with the pre-2010 model Piranha Tubeless Ready tires with the kevlar bead, although with tubes installed. I have thought about the benefits of tubeless before, but was not ready to try to convert a non-tubeless wheel to use a non-tubeless tire. Since I found myself with a pair of Tubeless Ready tires, I was ready to take the plunge. Also, I think the Hutchinson tubeless tires (the Piranha for smoother courses, and Bulldog for muddier), are designed with tougher, stiffer casings for use without tubes, so if you use them with tubes it really decreases the ride quality.
I first set out to find a conversion system for my wheels. There are a few commercial kits (Stan’s Cyclocross or the CaffeLatex Racer 29er kits), or you can go Ghetto Tubeless and use sealant, 3M tape, and a cut up old tube. I chose the CaffeLatex kit since it was available at a shop nearby. It seemed pretty expensive ($70), but did have valve stems with removable cores, an injector, sealant, and reinforced tape. I haven’t used Stan’s, but I found the sealant to be very interesting. It is very light and foamy, and the bubbles coat all areas in the tire to help seal spoke holes, the tire bead, valve stem, etc. I have had a few trouble spots, and the sealant seems to work well.
I cleaned the rim bed, ran the tape around the rim, and poked a hole for the valve and inserted it. I then put the tire on and was amazed that despite its loose appearing fit, it inflated easily to about 50 psi with my floor pump, but was losing air quickly. After adding sealant I saw many bubbles from the rim bead and a few dribbles from spoke nipples, but after a quick ride and a few hours the tire was holding air.
Update 10/27/10: You may have seen recommendations to seat the bead of your tires with a CO2 inflator. You may have to do this, especially if you have a deep center channel on your rim (the tire bead will sit there, instead of sealing against the rim wall), or if you have a sub-standard pump, or if your valve stem has less flow due to sealant over time. Be careful using CO2 cartridges with latex based sealants. The cold can shock the sealant and leave you with a messy, congealed, unbalanced and unsealed tire. Try to seat the bead without sealant, deflate, add sealant, and pump. If you must use CO2, keep the valve at the top, so the sealant is at the bottom, and don’t shake/spin the tire too soon.
The larger volume tires seemed to be riding well with tubes at about 35 psi, but part of the advantage of tubeless is running lower pressure, since a rim hit does not mean certain death. I put the tires at 31F/32R and they seemed to ride well, but when I gave the tire a good pinch to push the bead from the rim, I was greeted with a hiss and squirt of sealant! The air loss was tiny, and I wasn’t sure if I would encounter that type of force while riding, so I decided to give it a shot.
My first few rides went without incident, so before my first race I decided to go on a good shakedown ride and see what they could handle. I rode up a rocky, loose mountain bike trail (Eagle Trail in North Boulder) and found the traction was impressive, but I was having tiny burps when I would squish the tire to the rim on sharper rocks. My tires were covered with flecks of sealant leaving trails from the rim bed in the dust, but surprisingly I had lost very little air. On the way down I apparently hit a rock pretty hard, as my rear tire quickly went flat, spraying sealant all over me and my bike. I had pinched a hole through the tire casing.
I came prepared and put a tube in the tire, although it was a little difficult to remove the tight fitting valve stem, and was on my way. I got home and simply patched the tire from the inside with a large standard tube patch. The tire bulged a teensy bit, but I was not too concerned about it. I also added the original rim strip to increase the tire diameter and found the tire fit marginally tighter, but the small burps remained. I raced my first two races with this setup without incident. A few days ago I went to wash my bike (NOTE: a good time to find mechanical problems, and another reason to wash your bike frequently), and saw what appeared to be a mushroom growing out of my tire. Only a few minutes later the patch popped and my tire was flat again.
With a race coming up, I attempted to patch the hole a few more times, but without success. I threw a tube in the tire the morning of last Saturday’s race as a stopgap. At the race I saw many people with flat tires due to Goadhead thorns, and hoped I wouldn’t be one of them, as my rear tire now was without sealant. A few laps in, I noticed my rear tire was almost flat, and lost nearly a minute in the pits changing wheels.
As I’ve said previously, I am happy to have improved cornering ability, but the minor advantage is not worth the risk of a DNF. I had heard the 2010 Piranha tires with the Carbon Bead fit much tighter, so tight in fact that many people cannot mount them, or have damaged the bead forcing them on the rim. Since my tires fit rather loosely I decided to try a new tire.
After mounting the tire today I knew I had found a very good setup. The taped Hurricanes with the Carbon Bead Piranhas are a very good combination. The fit is tight, but easily mounted. The tire easily inflated and almost no sealant was seen at the rim-tire interface. The tire does not leak air no matter how it is manipulated, even at 28 psi. I will be racing this setup for the rest of the season, except I’ll be borrowing some narrower tubulars for UCI races, and I also have some WTB Crosswolf clinchers around in case I find myself in serious mud.