2012 is my second season of cyclocross racing. I first discovered cyclocross just last fall, when I borrowed a low end Specialized cx bike, finished in the back third of the pack, and loved every minute of it. Within a few weeks, I went out and bought an Orbea cyclocross bike, reviewed here.
That bike came with stock Vittoria cx clincher tires. I promptly blew out a sidewall on the front Vittoria in a race when I hit a root, riding through a muddy ditch. I replaced it with a Grifo Challenge clincher in the front, which is a perfectly good tire.
This year, though, I went tubeless on my 29er Specialized Carbon Comp mountain bike. I was really impressed by the difference in handling, and the lower pressures that I could ride without worrying about pinch flatting. I also love the idea of sealant instantly sealing up most flats, although I haven’t even punctured my Specialized mountain bike tires yet and have yet to see the sealant in action.
So when this cyclocross season rolled around, I started wondering about tubeless tire options for cyclocross.
I had first looked to see if Specialized had any cyclocross tires that they described as “2Bliss Ready,” which is their branded terminology for tubeless. But I didn’t see any of their cyclocross tires listed that way. So it was on to Stan’s tires, which I didn’t have any experience with, but trusted that they would seal up very well tubeless. I saw that Stan’s made a cyclocross specific and tubeless specific tire, and I figured I would try it.
I bought my tires directly from Stan’s.
My Orbea Terra bike has lower end Ksyrium Equipe wheels that were NOT tubeless ready. It’s evidently fairly easy to install Stan’s tape and convert wheels to tubeless yourself, but I took my bike to Dallas Bike Works and paid to have them convert the wheels instead. I didn’t want to do it poorly and make a giant mess with sealant, or end up with a tire that didn’t hold air well.
It turns out that I didn’t use Stan’s sealant with the tires. I ended up using Caffelatex sealant instead, because I have had a good experience with that sealant in my 29er mountain bike tires.
When I first got the bike back, the rear tire held air very well, but the front tire was losing 10 to 20 pounds of pressure overnight. Eventually, it sealed up all the way. Both tires still lose pressure faster than my big 29er tires. They might go down 5 pounds in a night until they get into the low 20s, where they will tend to stay. But I believe this is common with tubeless cyclocross tires, because there isn’t as much air volume in the skinnier tire, so pressure goes down faster.
The Raven tire is a 35 mm tire, which gives it more grip in the dirt than the 32 mm Grifo tire, or the 32 mm Vittoria. It has a very fast tread pattern though, and I find that it rolls extremely well, even on pavement.
One of the first things I noticed about the tire was how low you can run the pressure, according to Stan’s. If you ever look at most clincher cyclocross tires, they’ll always have crazy sounding “minimums” of 45 or even 65 pounds. I actually took those minimums at face value for a couple of races in the beginning of my cyclocross days, and bounced and skidded all over the place. I now believe that those minimums must be decided by lawyers, and not manufacturers.
The Stan’s Raven tubeless cx tires have a minimum of 22 pounds, and a maximum of 65 pounds. To give you an idea of how low that is, I run 28 pounds on my huge volume 2.2 29er tires — and that’s running them tubeless! So 22 pounds as a minimum sounded incredibly low to me.
When I first started riding them on a cyclocross course, I set them at around 28 to 30 pounds, both in the front and the back. (I weigh 150 to 155 pounds.) The tires were grippy, and they didn’t bottom out to the rim when I rode over rough stuff. Seemed like a good pressure.
Not being able to leave well enough alone though, I decided to go even lower. At the second week of the Woodcreek race series, I went for 26 or 27 pounds, both in the front and the rear. It went very well during the warm up, and it seemed like this was going to be a better pressure for me.
But during the race itself, disaster struck and I “burped” the rear tire on a hard corner, losing a large amount of pressure. I was in second place in the C race at the time, and feeling great. I slowed down in the corners because of the mushy rear tire, and was overtaken and dropped back to third place. With only two laps to go, I thought I was going to make it to the end in the top three. But I leaned too hard into a corner again with very that low pressure and lost all the rest of my air and dropped out. (I didn’t have any spare wheels in the pit.)
Before I went tubeless on my mountain bike, I had never heard of “burping a tire,” so I’ll explain it in case you aren’t familiar with it. Basically, since you have no tube, you are sealing in all the air directly in the tire and wheel. If you run your pressure too low and lean too hard into a turn, the force of your turn can unseat the bead of the tire from your rim enough to let a small (or large) amount of air leak out. It makes a weird noise when that happens, which I imagine is why they call it a burp.
So after that experience, I would say that 22 pounds might be a legitimate low pressure for a front tire. But for the rear tire, it does not work for me, with that tire and wheel combination and my style of riding.
Since that incident, I went back to 29 pounds, front and back. I’m probably going to try 26 or 27 on the front tire again, but won’t go lower than 29 in the back.
[Update on the front tire. I raced at 27 pounds in the front, and ended up burping the front tire when someone ran into me from behind in a technical turn and knocked me down in a forward direction, putting a sudden heavy pressure on the front tire at an angle. Since then, I’ve gone up to 29 to 31 in the front, and 31 to 35 in the back and have not burped either tire again.]
One great thing about these tires is that I’ve been able to corner hard enough through loose dirt to drift the front tire and lose grip, but still hook back up again. On my Vittoria and Grifo tires (which I had to run at a higher pressure because of the tubes), sliding out the front tire was almost always the precursor to a crash, or at least an unclipping of my inside pedal to dab my foot.
I have not flatted these tires yet, or even caused the sealant to seal up any small punctures.
I ride them on the road sometimes, but the tread is still holding up very nicely. I think Stan’s chose a very good balance of grippy rubber that doesn’t wear out too quickly.
Overall, I recommend these tires if you are looking to go tubeless. Tubeless is a much cheaper and more practical option than buying a set of tubular wheels and very expensive tubular cyclocross tires, just so that you can run your pressure lower than a clincher.
Have you ridden these tires, or do you have questions about them? Leave a comment with your feedback or questions!