I don’t think he has run anything’s less than the Pathfinder 47’s this year……but I can’t swear to it.
He used the endurance casing 700cx44 Rene Herse at Unbound for mud clearance.
But yeah he’s pretty vocal on Bonk Bros about going as wide as can fit on a gravel bike. I’m pretty sure he’s said multiple times there’s no point to the 42/38 pathfinders if your bike fits bigger.
I’m curious to see if he commits to going full 29x2.2/2.35 for all his gravel events next year. He will have a new bike sponsor but hasn’t said who so it may be one with better bikes for this sort of tire size.
What I’d really like to see is someone in the mix on the 3T Extrema.
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Those are aero watts but you have to consider rolling resistance watts too so there may be less difference than the charts say.
Joe
Of course you’re correct. I overthought his question and extrapolated into the purely aero direction.
One of the best comparisons BRR does is test the same model tires in different widths. The few tests performed have shown that there is no clear outcome for tires that should be more similar to themselves (in larger/smaller width) than other tires in the same width. Which is interesting looking at the overall gravel category where in many cases, the narrower versions of the tires have lower rr than the wider version(s) - from what I can see often due to the thickness of the casing remaining the same as the tire gets larger.
Which seems to indicate one’s mental model should be that rr may be higher or lower as the tire gets larger, but aero losses will always be higher for the larger tire.
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Just wanted to throw this out there. Tufo Thunderos now come in 700x48 - perfect for a big gravel tire. I just ordered some for my Cutthroat. I’ve been running Race Kings, so I’ll be curious how these compare.
They’re hard to find in the US but pricing here is reasonable even with shipping.
The 40 and 44 versions look pretty fast…hopefully the 48 is too.
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I actually received the 700cx48 Thunderos today from R2, they feel incredibly supple in the hand. Won’t be able to ride them until next week but I expect they’ll be very fast.
My idea for now is to go 29x2.35" Thunder Burt in the front and either a 2.25 Thunder Burt in the rear or 700cx48 Thundero depending on the course.
I’ve been doing a bit of testing and concluded I don’t gain much from a rear tire larger than 2.0" for general use. The pedaling feel of larger tires on pavement and smooth gravel is unmotivating (slow feeling) even though I know better, keeping it a little narrower gives me the lively feel I like, apparently without sacrificing much speed on the rough stuff.
This is a segment I use for a lot of testing - it’s a combination very old road bed into singletrack with rocks and roots - rough bumpy climb to fast flowing descent with some flat corners, some loose gravel corners, and a few tight banked turns with a couple small drops. Good test for a gravel racing bike, IMO.
Here are two each of my fastest times on my drop bar MTB running 2.35f/r and 2.35f/700cx47r, with the baseline an average flat-bar MTB hardtail run. I can tell the difference with the smaller tire in the rear but it doesn’t seem to make any difference actually getting through the segment. I’m going to keep testing.
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Is that saying curly bar bike is 15 seconds faster or slower?
Sorry that isn’t clear - yes, at my best effort the dropbar bike is about 15 seconds slower than an average run on my MTB.
I can see how this is confusing now, I wanted more to show the dropbar difference between rear 2.35 or 47 is very small for this segment instead of comparing directly to MTB speed.
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Yeah I figured that, I am just easily distracted
FWIW, I recently did some roller testing of a Super Race version of Schwalbe’s Thunder Burt back-to-back against a Super Ground version. I needed to buy a couple of new tyres anyway, so I bought one of each version. In view of those expected BRR results a while ago for Racing Ralphs with those two casings, I was keen to test both types myself.
Both were 2.35” width. Both were brand new and unused, bought in late 2023. This should hopefully avoid differences coming from one tyre having aged or be more worn than the other.
It was an ABAB type test. The results confirm that the Super Race (purple in the plot below) is a faster casing than the Super Ground (red). All the usual caveats and doubts apply to this data, discussed earlier in this thread; whether roller testing creates a bias due to the small radius, and even whether tyre ranking results from roller/drum testing translates to real world CRR’s when riding off-road.
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Thanks for doing this! I’m curious about a few things:
- Did you do this test on rollers or out on the trail, or…?
- If you did it on the rollers, What’s the diameter of your rollers?
- If you did it on the rollers, do you know what the diameter of the BRR rollers is?
Thanks!
Hi, to answer you questions:
- Yes, I did this testing on rollers.
- The diameter of my rollers is 8.4 cm (3.3 inches). The method I’m using, which is borrowed from here, accounts for roller diameter and applies a correction to the CRR values (since the smaller roller diameter causes a smaller contact patch).
- BRR uses a drum diameter of 77 cm (30.3 inches).
It’s worth mentioning, in case it wasn’t obvious to everybody, that these CRR values won’t be correct for off-road riding. Drum testing and roller testing only measures the tyre hysteresis losses, whereas when we ride off-road there are other losses that manifest themselves as additional rolling resistance losses. Having said that, those tyre hysteresis losses are present off-road too, and so personally I believe that the relative difference between tyres seen in these kind of drum and roller tests indicates which tyre is faster off-road. However, even this last point is matter of debate, so some people think that results coming from tests like BRR’s are not applicable at all to riding off-road.
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Thanks, at least this helps to confirm that roller testing is consistent across big variances in roller diameter…?
Thanks for the continued testing and data. I went with Super Ground Thunder Burts (for now) for the additional puncture protection, not having had good luck with the older Super Race equivalent.
If I’m reading you graph correctly, the difference between SG TB and SR TB is slightly more than the difference between SG TB and the Continental Race King Protection?
I’m also wondering if the puncture protection setup for SG/SR has an influence on roller data/crr, dependent on the type and size of the roller.
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I am one who doubts a lot of what I see on BRR, yet…
I do think Schwalbe’s MTB tires are the fastest I have ridden. (I do RR combo, since often have a bit softer ground). I’m bigger, so have always stuck to the SG sidewalls.
I also am an addict of the terra speed. They don’t last, like at all. They somehow dry out quick, and the tread wears quick, but, changing to them was a noticeable speed improvement. I’ve never flatted them, even on courses they were way out of their league (VT overland).
If its muddy, I use the Schwalbe G-one bites, which are faster than they should be for the grip they provide. I haven’t checked BRR in a bit, but I remember looking into why they felt so fast after using them, and BRR confirmed my experience.
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Yeah, this thread has so far mainly focussed on minimising rolling resistance, but often it’s best to compromise on CRR for a more robust tyre. I stopped using Scwhalbe’s older Liteskin casing a few years back for that reason. Like you, I’d be equally happy running the Super Grounds for their added protection as compensation.
That’s right, the difference between the SG and SR casings seems to be similar to the gap to the Race King. The only thing I’d say on that is that my Race King tyre is a few years old now, bought in 2020, and although the level of wear was qualitatively the same as the 2022 TBurt I compared it against, I wonder if the rubber ages somehow. I remember some BRR tests where they showed the Conti GP5000 gets slower with age. Perhaps it’s not be the same, but it got me thinking.
I remember the discussion earlier in this thread about roller diameter. Yeah, maybe it does inflate the differences between two types of casing. I looked again at Tom Ahnalt’s blog and did a quick google search, but I could find anything quickly, so that remains another uncertainty.
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I don’t think it’s just continental, rubber oxidizes as it ages, so old tires are probably slower, and they definitely become less grippy as they get older.
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Thank you. It makes me feel good about my purchase. I won’t be able to ride outside until late March.
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Dylan Johnson released his 2024 sponsor and gravel bike: FB Link
Partnering with @feltbicycles is me walking the walk and not just talking the talk. I know, I get up on my high horse a lot whenever the topic of gravel tires comes up (I think that just comes with racing gravel
). Plain and simple, I think the industry has gravel tire size wrong. Whenever I test tires I always come to the same conclusion, wider is faster and the current crop of lightweight XC mountain bike tires are usually faster than their gravel counterparts. I’m not saying I’m never going to use a narrow gravel tire again but I find myself gravitating towards wider and wider tires every year.
Felt’s Breed Carbon is a glimpse into the future of gravel race bikes in my opinion. It’s hard to find a race focused gravel bike with aero tube shapes that doesn’t have every possible rack and fender mount that racer don’t need that can fit 50mm or wider tires. Well, currently in this bike are a pair of Schwalbe Thunder Burt 2.1s measuring in at 51mm on @reynoldscycling G700 25mm width rims and there’s still a bit of room.
Throw in 4 bottle cage mounts for long hot gravel races, suspension ready geometry for those “drop bar hardtail” courses and this incredible custom paint job and I couldn’t be more stoked right now.
This is an exciting development. It took a long time to spin up industry and institute around 700cx40ish gravel tires mainly because the thought leaders were relatively niche. I think DJ is a much more popular personality and is a good signal for this trend.
I’m wondering what he means by “suspension-ready”? It looks like a 40-50mm gravel suspension fork would drop in without changing the geometry as much as a more normal gravel bike but it doesn’t seem that much different than more normal mid-range gravel geo? Perhaps more discussion for the drop bar geo thread.
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Yowzers… That seems like a step backwards to me, but he might not have had a choice… They must’ve ponied up some nice funds for him, and good for him, he’s worked for that and realistically this bike won’t affect his 16th-17th place finishes. But that frame is just hideous. It looks like an e-bike. The fork looks good(420mm length for reference, hence the “suspension ready”), but the hump in the top tube/head tube zone, the cable routing that negates any aero advantage of the frame that they claim, and the seat tube/post cluster is just nasty… Then topped it off with his horrible saddle position and some Coefficient RR bars…
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