Is a MTB tire the fastest and best tire for Gravel racing?

Could you share their top 5?

Hey,
indeed - for top performing tires in regard to rolling resistance one has to look at the top XC MTB tires, not the typical gravel tires.

I have just the right article for you folks:

In it, I share a light on all the various aspects. I include my own combined rolling resistance and aerodynamic tests, I refer to the also already in this thread mentioned Swiss Side and Silca results and discuss those and further sources and by all these show that indeed - for the ranking on which tire is fastest you can rely on drum tests like from BRR. Regardless of the surface you ride on actually. Since a fast tire on the drum stays a fast tire on the trail (according to rolling resistance - if you need special considerations for grip, that’s another topic).

Conclusion: with the Conti RaceKing you gain on many fronts compared to a standard gravel tire, say, a 40 mm Schwalbe G-One RS:

  • faster rolling
  • more robust tire / more protection against “oh shit” moments in a dustriddled bunch with no view on the trail in front or your tire
  • more tire patch on the ground, better grip and cornering

You only loose in regard of aerodynamics. But - to be concerned about this, you will need to run an appropriate wheel with your gravel tire in the first place. So - if you are combining your 40 mm Gravel tire with, say, a Nextie 700x45 AGX (with 40 mm external width), then you’re game. If you run a 45 mm Gravel tire with a run of the mill low profile (or super narrow aero rim) - don’t bother. You won’t get any or only miniscule disadvantage by running the RaceKing on a mtb rim.

For the record: for my setup, I would draw even between a Schwalbe G-One RS 40mm on my Nextie 45 AGX wheels against a Conti Race King 2.2" on my mtb wheels at around 20 km/h. But - I would still reap the benefits of a more robust tire and more confidence in corners etc. in case of the RaceKing.

14 Likes

This is such an amazing blog post and well executed test! Well done.
That‘s the way we should evaluate tires.

2 Likes

That guy’s blog is great. In this other article, he says what I’ve been thinking for a few years now every time I read a Jan Heine article:

Unfortunately, unfortunately – with all the knowledge and experience that Jan Heine and his team have acquired, they are clearly neglected on the topic “sufficiently large test length” on the topic just mentioned. Time handling with normal stopwatches and measuring lengths for only around 15 seconds lead in the graphics listed there as an example between 700Cx44 and 700cx28 tyres at times in the range of exclusively 15.x seconds. And in the range from 15.19 to 15.70. Here, differentiation is still foremost, due to the extension of measurement errors, even according to the means. Well, Jan Heine wanted to show that there are no differences between the two tyre dimensions.

1 Like

I just mentioned this in a different thread where I announced a bunch of cool cycling web tools I made, but I tried to answer this exact question, with physics!

On this site GPX Route Speed Estimator for Cyclists: Multi-Surface, Weather, and Nutrition Strategy you can upload any route you’d like, I even added some preset routes, like Big Sugar, you can paint in different surface types, and choose whatever bike configuration you want, and see what’s faster!

I added road/gravel/CX mtb/ and all-mountain tire choices. I used rolling resistance values from https://www.bicyclerollingresistance.com/ the CX mtb tire is identical to a 57mm Thunder Burt Super Ground Addix Speed tire, the gravel tire is essentially the 40mm G-One RS Super Race.

I account for the differences it makes on chunkier surfaces, the corning speed difference and the aerodynamic CDA difference between said tire choices.

It’s a totally free tool that can even use forecasted weather data and run the simulation against it, interjecting wind/humidity and all other sorts of things. It even takes into account your elevation and the air pressure, so, have worse aerodynamic tire at a higher altitude, like Leadville, will not matter as much and perhaps then the mtb tire will have less drawbacks, I really tried to account for everything.

If you try it out and have any feedback, please let me know :slight_smile:

2 Likes

20km/h equals 12mph…that’s pretty slow. I’d pick a MTB tire at those slow speeds as well because aero wouldn’t matter as much.

Have you considered the Schwalbe Thunder Burt 2.10? According to BRR, this tire is actually faster than the Race Kings….

If yes, the SuperRace should be faster than SuperGround no?

Thanks

Yes, I had considered those.

2 things: Rankings of tires tend to stay the same across all the pressures BRR is testing. But the difference between 2 models can become smaller and bigger with lower or higher pressures. In the pressure range I tend to ride my 2.20 tire (1.8 bar) the Thunderburt and RaceKing reach the same results in BRR.

So it comes down to personal preference of the tread and ride feel and to weight. Haven’t ridden those yet. But quite a while ago I ordered 4 of those at once because I knew how notorious Schwalbe is with their weight indications. Some tolerance is expected. Especially for tires. But for my taste Schwalbe is on a whole other level as most other reputable brands. If they say a tire weighs 615 g it’s never 615 g. It’s also never 630 g. It’s always way higher. Seriously, I can only attribute that to some very weird brand decision to blatantly lie about its tire weights. Sorry - rant over. They have a few nice tires (not all of them, mind you).

But, case in point: look at the BRR data. 615 g is the specified weight of one Thunderburt given by Schwalbe, 680 g did BRR measure. Take the RaceKing: 605 g specified, 588 g measured. That’s what I call tolerance - you can also get a slightly lighter tire. Not a 10,5 % heavier one as in Schwalbe’s case.

To conclude my story: I found the same with all my ordered Thunderburts and instantly returned them.

4 Likes

Dylan Johnson had planned to run the TB as his rear at Big Sugar. However after a practice ride he noticed multiple weak spots in the tire that looked close to causing a flat, so he opted not to use them on race day.

On an XC bike, I find the Race King a little more versatile than the TB. Mainly just a little more traction with the knobs on the Race King but it becomes more pronounced once roots enter the picture.

2 Likes

I’ve been running the Thunder Burt 2.1" SuperGround on my Mosaic “Gravel+” bike, mounted to 30mm internal Nextie rims. They’re really nice on everything but the roughest, chunkiest gravel. They carry speed really well, and even cornering at 20mph+ doesn’t feel sketchy, and I’d say more confidence inspiring than the Conti Terra Speeds(part of this is probably simply the volume increase with lower pressure). In the past I had some 27.5x2.1" Pacestar Thunder Burts that were really nice on my old Hakka. I lined up to a few races with them, and really appreciated them on the downhill sections where I could easily roll away from others without having to pick lines as carefully.
I have the Conti Race Kings on a different build(Epic HT Drop Bar), and its hard to compare them directly to the ThundurBurts, but they’re comparable for sure. I’m pretty easy on my tires, with very few punctures over the last five years, so I can’t really tell which is more durable, but if I were to line up for a race today, I might lean to the Thunder Burts, just based on the fact I’ve got more miles on them without issue, and people are constantly talking about how delicate the Race Kings are… I did opt for the SuperGround casing after seeing the BRR results where the SuperRace didn’t look to offer much if any benefit.

6 Likes

That’s a really good point about the Super Ground and worth keeping in mind on future purchases.

Do you have pictures?

I’m leaning towards the SuperRace. And I only have 25mm internal. I’m not even sure they’ll fit in my MOG. Will try.

I don’t see any testing of the Thunder Burt SuperRace tires in BRR, do you have a link……I’m assuming these are more supple, lighter and faster.

No photos that really help with a closeup… I bet they’d fit… The front fits on my Crux, and the rear nearly fits, but would rub the front derailleur(GRX Di2). I feel like if I mounted them to my 25mm internal wheels, I could run them. The MOG has 50mm stated clearance, where as the Crux is a bit less, so I’d be inclined to think you might be able to get away with it. But also… do yourself a favor and buy tires from the Europe.
R2 Schwalbe
Bikeinn Schwalbe

I don’t think they’ve tested the Super Race Thunder Burt, but I’m extrapolating… They tested both version of the Racing Ralph, and the Super Ground actually was faster, and had improved puncture resistance, at only a 100g weight penalty. They mention not being impressed with the Super Race compound in a few reviews. I haven’t tried the Super Race, and am not opposed to trying them, but it hasn’t been a high priority after being happy with the Super Ground.

2 Likes

I’ve used both Race Kings and Thunder Burts on my MTB in the past, and I like them both. I did some roller testing of the Super Race version of the Thunder Burts last year, partly because I was frustrated that BRR never got to test the Super Race version. That roller testing was using the Tom Anhalt protocol. The Super Race Thunder Burts seemed a bit faster than the Race Kings based on my testing, but there wasn’t much in it.

See my blog here for more details.
IMG_0043

5 Likes

I’ve done Big Sugar on Pathfinder Pros 42f/r and 47f/42r now and I wouldn’t recommend anything less than 47f/42r for sure. The 47f was an improvement but still sketchy on that course even at 22psi with an insert. If I do that race again I will likely be on 650b wheels and 2.0-2.2" MTB tires. A 40mm suspension fork would also be quite welcome. We had a guy on a XC MTB hardtail in our group through mile 45 this year. We were doing about 19mph avg up to that point and he was keeping up just fine on 2.2 Aspens and was way more relaxed on the downhills than the rest of us.

There are just so many ways you can lose traction and crash really hard out there. The more compliant and grippy your setup is the better you will do. It’s almost a safety thing for that race! I saw some bad crashes right in front of me on some of those loose off-camber corners.

3 Likes

That’s a really nice article, I enjoyed reading that. I did some similar testing myself last year, using the Chung method to compare the relative performance of my MTB with 2.35” Thunder Burt tyres, to my cyclocross bike with 40mm Conti Terra Speeds, ridden around a grass field. The full blog post is here.

The method I used for that Chung testing was very similar to what you described in your article. For the analysis I fixed the CdA, CRR and weight for both bikes (although they were obviously different for all three of those parameters). Then, the difference in the virtual elevation profiles indicated to me which bike is faster. That difference might have been be due to CdA, CRR, or weight, and probably some balance of differences in all three. With Chung testing it’s sometimes possible to differentiate where the overall net benefit is coming from, but in the end, it doesn’t really matter, as we normally only want to know whether one bike is faster than another, regardless of the reason.

I found that the MTB was faster, presumably because the improved rolling resistance of the wider tyres had a greater effect than the aero penalties coming from the flat bars, the suspension fork, etc. All the testing I’ve done in recent years persuaded me this summer to convert my hardtail to a drop bar rigid MTB, like you did for your Canyon Exceed, which I now use for any dry cyclocross races. It gets me better race results than I get with my 33mm-tyred cyclocross bike (we don’t have tyre width rules in our local races).

6 Likes

Hey Nick, thank you. Each time I read this article myself I feel I need to polish the expression to work better within the English language. My first translation run still retains much from the way I wrote in in my native German. But if it gets the contents across I’m happy. :slight_smile:

That’s a lovely dropbar MTB you have there. Havent’t seen it yet allthough I’ve come across your blog in the past already. So I happily return the compliments. Love your testing and results!

2 Likes

What was the average speeds of your test runs between the Thunder Burts and the Terra Speeds? For my test runs between the 2.2 Race Kings and the 38mm Pathfinder Pros the speeds ranged from 18 to 19 mph for a 6 mile segment. I was only able to average 19mph with the Pathfinder Pros.

Thanks, and for what it’s worth I thought your translation was perfect, far better than I’d expect from a non-native speaker. I often review technical reports at my work from British people whose grammar is much worse than yours. I just wish I could speak German (or indeed any other language!) so I could read the rest of your blog.