XC Race Tire Thread

Actually, I found it was the opposite. I had 2.35” Thunder Burts, bought in 2022, and needed another one. However, I struggled to find the 2.35” version in stock during most of 2023, so I bought a 2.25” version instead. I was a bit dissapointed how narrow it was.

Both are mounted in the same rim type, a fairly narrow ~8 year old XC rim that I think has a 21mm internal diameter.

My 2022 2.35” T.Burt measures 2.30”
My 2023 2.25” T.Burt measures 2.11”

Measures in a few locations each with vernier calipers. Both have the Super Race carcass, in case that matters.


Not seen any mentions of pirreli scorpions.
Has anybody tried these?

The Scorpion RC looks like an Aspen but it tests slower on the drum test and is also not as puncture resistant according to BRR. But it is lighter. I believe I read somewhere that it may have better cornering grip than the Aspen. I’d be tempted to use it on the front with an Aspen on the rear, both in 2.4 size.


That is weird….i have 59.9mm vs 58.6mm for the 2.35 and 2.25 respectively. This is on 30mm internal rim and 20psi. I don’t know why mine are so similar….but this is what I’ve got.


That’s strange. Did you buy both at the same time? I bought my 2.35” tyre in early 2022, over a year before I bought the 2.25” tyre. I wonder whether Schwalbe and other tyre manufacturers occasionally change their tooling and make tyres smaller (bead to bead) to reflect the evolution of increasing rim width. I think I’ve seen comments on BRR that suggest that happens over time, albeit for road tyres.

Might get more replies in the XC Race Bike Thread:

I’ve heard other people find they are quite close. It’s a bummer that they aren’t a little bigger, but it seems like they are very fast, and not 2.2 like a race king.

Gah sorry I though I’d swapped threads….

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A few months apart…the 2.25 in maybe September and the 2.35 in December because they were sold out of the 2.25 until then. Weight on the 2.25 is 611 vs 700 for the 2.35. Maybe just chalk it up to variability I guess.


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Made the switch so the tires are on the other wheel sets now and…thunder burt is still faster, although not quite as much faster as last week. So maybe the wheels make a difference? I don’t know. Booster runs were super consistent. TB runs, much less so…but always faster.


Thanks for doing these tests and publishing the results, Joe. I enjoy following along.

Can you remind me the course surface and average speed? I wonder if the 2.6" KBs have some sort of aero penalty vs. the TBs?

Also, do you have a stack rank of all the tires you’ve tested? I know you’ve tested a number.

I feel like you’ve filled some gaps in the public tire rolling resistance database, and for that, we thank you!

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There is definitely an aero penalty comparing a 2.6 versus a 2.25 or 2.35 tire. I’d like to see how the 2.25 Booster Pro compared to the Thunderburt in terms of speed. The smaller Booster Pro would still provide better cornering grip than a Thunderburt.

I should but I don’t. It’s sorta like you’d expect….of the tires I’ve tested the dhf and butcher types are slowest then the ardent race recon race then boosters then Thunder Burt. Hoping to borrow my buddy’s race kings at some point. I feel like I’m getting somewhat consistent results now so I hope to keep testing.

There has to be but I’d like to test that too. I can do that on a paved loop at the house and only plan to swap the front tire for that. It’ll happen!

Yeah that and/or the kenda rush. I’d like to test the other xc schwalbe tires too on the front. Thunder Burt definitely has tiny knobs but it didn’t seem too terrible. One of the complicating factors is….is the grip that much worse or is it that you’re going that much faster? I feel like I can nail power targets but have trouble evaluating the grip.


Yep, makes sense. I’m most curious about some of the others you’ve tested, like the Nobby Nic and Fast Trak (IIRC).

I went from Aspens to them… they are maybe a bit slower… but they are sub 700g (with prowall sidewall protection) and they have much more cornering grip and also better in the wet.

When I rode Aspens sometimes I had to put Ikons on the front but now I can go F&R with same tires…

If someone has better RR tests than drum I would appreciate sharing the data…

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May i ask which model exactly? The XC RC one?

Some of my friends ride XC M and they look bulletproof.

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Cool. Thx for the answer.

Sorry to bother you again, but do you think the XC M will slow me down a lot? Are they much different than the XC RC? Since you’ve seen both in person i was kinda interested in your thoughts on one vs the other…

Thx in advance

Probably not… especially if you put it only on front…
But like a lot of things in MTB “faster” means higher avg speed on the whole route… if you lose a few seconds on some parts but gain much more on descents and corners than the tire is faster…