Tubeless Testing Summary Report

Tubeless has been the standard for most active mountain bikers for a bunch of years, and it’s been an increasingly viable option on road for a while. In cross, the adoption hasn’t been as smooth. A new crop of tires and rims has held promise that 2015 would be the year that tubeless became a viable option for cross. Since we’re inveterate testing nerds, we needed to see for ourselves if it was ready for prime time. Here’s what we learned.

But first! a two second primer on tubeless. You need to prep your rims to make them airtight. Ours come sealed with tape, so there’s nothing left to do there. Beyond that, you’ll need tubeless valve stems and sealant. There’s nothing fancy or complicated about either. You can buy valves or even make them out of old punctured tubes (just cut the stem out, but it has to be threaded and you need the nut), and there are several brands of sealant that work just fine.  

You're gonna need to getcha some of these

Testers were Michael Wissell of the Cuppow/Geekhouse/B2C2 CX Team, who’s really really good at cross, and me (Dave). I kind of suck at cross but love it so long as there isn’t much running or getting off the bike of any sort involved.  Neither of us is too heavy, I'm the fattie of the pair at a fighting 160 pounds. Most testing occurred on disc brake bikes, on Stan’s Grail and Pacenti SL25 rims.  Pacenti SL23 (rim brake) rims were also tested. The inner shape of the SL23 and the SL25 are indistinguishable, and the Grail is also very similar.

Testing protocol was basically “throw whatever hatred and evil you’ve got at the things, and see how they do.” This included terrain which no cx bike should ever see, as well as terrain that every cx bike should see, cobbled roads, drop offs, roots, rock gardens – you name it. All tests were done with sealant (either Stan’s or Orange Seal, both of which work well), and two wraps of the tape we supply on alloy rims (TESA 4289, if you want to go get some).

Partial class picture

A successful test means that we unreservedly recommend the tire for use at low psi, with little to no risk of burping. In general, for us, this meant pressures down to around 22 front, 25 rear. Security of tire/rim interface was the overwhelming consideration in these tests. Any tire’s success in that measure doesn’t mean that either of us particularly like or plan to use it, merely that if you like that tire, feel free to use it because the shit works. Well.

If a tire is not specifically listed here, it means we haven’t tested it. These results are only applicable to the rims on which we tested. Success of any partial combo should not be assumed, nor should it be assumed that a tire we found not to work with our rims is a flop. It may work great on some other rim(s).

We’ve included some notes on each tire.  Enjoy. 

Tires We Don’t Recommend:

Challenge, Clement clinchers (can’t wait until they come out with tubeless), Kenda non-tubeless, Kenda tubeless (these probably work great on some rims, and the Stan’s CX team uses and endorses these, so YMMV), Schwalbe non-tubeless (these didn’t even inflate)

Tires We Recommend:

Hutchinson Black Mamba Tubeless 34 Weight: 348g Inflated width: 33.75. A file tread-ish tire with side knobs that seems to like grass more than a lot of other file treads. Probably great in frozen conditions, which we fortunately haven’t yet gotten to try. Seats with a loud bang. Comparable to Clement LAS, Challenge Chicane, Kenda Happy Medium

Hutchinson Toro Tubeless 32 Weight: 330 Inflated width: 32. Dave’s favorite all-rounder, Mike likes it but not as much. It may be a better tire for less aggressive riders, giving less of a loose and fast feel, with a more defined and secure traction limit. Works great on hard, loose over hard, hero dirt, slight mud, and short grass. Miserable in sand and loose dirt. Soap the beads when installing to ensure easy bead seating. Seats with a loud bang.  Comparable to most of the mtb tires that Dave likes – not a traditional cx tread.

Maxxis Mud Wrestler EXO TR 33 Weight: 362 Inflated width: 33. Mike’s favorite all-rounder, which he finds works well on everything but deeper sand.  Looks a light beer version of a mud tire, but not a top choice for really muddy conditions – it will pack up with gloppy mud. Can be hesitant to inflate with pump, but it can be done reliably. A compressor inflates it instantly. Comparable to a Clement PDX or Challenge Baby Limus.

Vittoria Cross XG Pro TNT 31 Weight: 390 Inflated Width: 32 This is a Grifo. The sidewalls are quite stiff, but run at low pressures (22 is fine in the front), it feels not as good as a tubular but WAY better than a clincher at the pressure you’d need to not pinch flat. This is the most secure tire/rim lock I’ve ever seen. I don’t think it would burp at 15psi. It’s fairly heavy, though. Comparable to a Grifo, which it is, and as such it’s just about as good a grass tire as you’ll find.

WTB Cross Boss TCS Light 35 Weight: 410 Inflated width: 36.75. This thing is HUGE. If you use this, people will comment on the width. Inflates instantly, seats with a soft bang.  I repeat, this thing is HUGE. Lower profile and more tightly spaced knobs than the Toro, with basically no side knobs – the tread pattern doesn’t overhang the sidewalls at all. Works well with insanely low pressure, and turns you into a hero in gravelly turns.  

Plus size model

Despite what we’ve said about inapplicability of these results to any tire not tested, we feel comfortable that the Vittoria TNT and Hutchinson Tubeless series tires not tested would have similar tubeless performance.

Weight and inflated width are both measured brand new out of the box, with pressure set to 30psi. All tires have become at least slightly wider over time.

So there you have it. As many many many people have pointed out to me in the last weeks and months, tubeless doesn’t feel as good as an FMB tubular, but when was the last time you were able to switch your FMB tubulars to a different tread on the same wheel after your last pre-ride? They’re not for everyone and every purpose, but for what they’re good at, they’re great. 

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I really don't have a preference. They are very similar. We sell both, some people have preferences.


Andrew – I have a lot more use on the Cross Boss as a front than as a rear, and I haven't been using it too much lately. For one because mine got a rather large thorn puncture and you don't even want to know what our tire bills have been this year, and for two because I kinda sorta have this thing where if we're racing cross and the rule is pretty much that a tire should be max so and so width, then maybe we ought to not worry about .5mm here or there, but 4+mm over the line feels weird to me. TOTALLY a personal issue. Although they do make you into an absolute GOD in loose or gravelly turns. Holy crap.With that in mind, I've got no issue running a Cross Boss on the front at 19 on a Grail or SL23 (I'm 160# and apparently somewhat fluid on a bike). I'd guess that 23 would be about right for me on the rear? To me, the feeling of squirm at low pressures will be the liability that tubeless may just have to live with vis a vis tubulars at similar pressure. They can do pretty crazy low pressures, and in terms of the suspension function – which is nothing to be disregarded – they're incredible. But when you're adept at driving the bike to really engage the tires and "feel through the wheels and into the tires" in a turn, a quality tubular is going to have the edge. The balance between the logistical positives of tubeless versus that on course advantage for tubulars is where the decision will get cut for most people. As a guy with too many balls in the air who's good enough to finish the elite race on the lead lap but in no danger of podium-induced altitude sickness anytime soon, tubeless works out great for me personally. It's the 4 extra hours per week I don't train, and the 4 extra beers per week that I have, and the ever increasing number of birthday candles I've blown out that are my limiters. If I was good enough I'd still be good enough on tubeless. I generally race at maybe 2psi more than the bottom limit of any tubeless tire, just because I know the suspension is still there and squirm ain't that cool. Now that they actually work, where before they just plain didn't. I think a Cross Boss at high 20s would be torture. That would be like riding around on a pogo stick. Ben – Happy to do it. I'd just go 32 in your shoes. I was on 28/28 Iron Cross at about 10# lighter than you, and found them basically stiff enough, but to me there's very little downside to more spokes. Dave


Hey Dave Thanks so much for the detailed reply. its really interesting to hear the differences from someone who has build and tested both wheels extensively. What about the number of spokes 28 or 32 ? im about 78 kg and the few extra grams of 32 don´t bothers me.CheersBen


Did you find a TP you liked with the Cross Boss? I am 165 and I can drop them down to 20 and they still feel good in the corners and grip well on steep almost run ups, with no bottoming out. However, I have had a few instances where the tire either just skidded on wet grass or folded over on itself in hard cornering at pressure in the mid 20s. I have also heard of people liking these in the high 20s. Did you find a so called "sweat spot" for these tires?


Hi Ben Sorry for delayed response, I should turn my notifier back on but my email gets freaking clogged.Anyhow, the primary driver was an impact I had where the Iron Cross I was using got just obliterated. As many times as I've had to tell people that crashing into stuff is unpredictable and chaotic random stuff might happen and "that shouldn't have happened" doesn't really apply, my considered judgement was that the damage was excessive for the impact. That wheel was replaced with the first Grail we ever built and it was an instant "oh yeah, digging this" from lacing through riding. The road use ability of the Grails is great, and they take spoke tension much better than Iron Cross (100kgf is really not enough drive tension on an 11 speed hub, even with 135QR or 142TA flange spacing), and they're more radially stable than Iron Cross rims so the installed tire decreases spoke tension less. Plus the tubeless interface is a bit deeper on Grails which is negative in that small (generally meaningless) dents are a more likely occurrence, but we find that many of the tires we really like set up SO securely on Grails. How was that for a text block?Dave


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