The real world confirms these results. Ted King has won Dirty Kanza on 650B and 700C tires, while most other racers were on 700C, because their sponsor’s bikes and wheels were designed for this tire size.
Besides incredibly faulty logic, the image of Ted King above this caption shows him riding 700c wheels. 
(But yes, Ted did ride 650b wheels when he won in 2018. The point is that lack of accuracy in any Rene Herse “study”)
He rode 650b in 2016 - Schwalbe G Ones
In 2018 he was on 700c Maxxis Rambler
Which makes their “real world” claim all the more silly……
At least to me, the 650 debate is totally moot. I have a garage fully of nice 700c/29er wheels and tires, and at 6’3” I want (if anything) bigger wheels, not smaller. My Lauf has reasonably aggressive geometry while fitting big 700c tires, albeit in a 1x-only format. I’m 100% not buying a gravel bike that can only fit big rubber in 650 format, and I don’t think I’m the only one.
The one thing that interested me in the article was that bigger tires on 650b was the same diameter as smaller tires on 700c. The example was 28 to 47 I believe. Now say a gravel bike fits 42… but in 650b you can go to 2.2. Does the bigger tire capability of the 650b negate some of the “diameter” advantages of 700c?
This statement is fair, but the argument is simply post-doc justification.
The contra-positive doesn’t stand up to logical review. The contra-positive would be:
All of the experimental data are consistent, therefore the experiment must be well-designed.
Here’s why:
All of the experimental data could be consistent without a repeatable methodology. The best examples of this are in social science for the last 10 years where the “P-hacking scandal” has gotten out of control.
Experimental trials where the starting states aren’t exactly the same can be completely legitimate. As others (@OreoCookie) have noted, you just have to have reasonable comparison of changes from baseline, along with well-defined and reasonably-calculated error ranges.
A more consistent argument would be (I haven’t read the BQ article, only the blog posts. So this is based on the blog posts):
The experimental trial is not robust because it’s not repeatable. There’s not enough specificity in the methodology to accurately repeat. Here are the area that make it vague:
That’s a reasonable set of arguments as to why the trial isn’t robust.
Alternatively, if those were available but you could show that they were done incorrectly, then it would be a legitimate methodological argument. E.g., error ranges were set too narrowly to be accurate, because there were only 5 trials for one variant, but the results of 2 of those trials were outside the claimed error range.
I agree with your conclusion, based on the first bullet list shared. I’m just observing that getting to that conclusion from the experimental data doesn’t work because the logic fails in reverse.
I totally agree with you - if you’re 6’3”, ignore 650b because some manufacturer will design a frame in your size that runs big tires on 700c!
But I’m 5’7” and usually ride XS frames (long legs, short torso - therefore I need short top tubes).
The frame options available to me will only run big tires in 650b, so I’m glad those wheels exist - for me and the rest of the cyclists who are my size or shorter…
What’s the saying? “Horses for courses”?
Hopefully we continue to live in a world where bikes are designed differently for different sized people, so that everyone can enjoy the type of riding they want!
This is the paper that always comes up related to 29er wheels: The Tractor Paper | but note it’s really about soft surfaces.
In the end I think the variability of surfaces and speeds as inputs is too broad to come to any good conclusions and in the end it’s as much of a roll of the dice as tire pressure on any given course. I’ve had all the wheel sizes from 26" Rat Trap Pass up to 29 x 2.2 Race Kings on purpose-built drop bar bikes and they all have had areas where they shined, but the reality is that in the majority of hours put on them they were all at least OK. But there are also suprises - on the Gering Nebraska course that is now the US Nats (?) there was a sandy section where on 26" slick Rat Trap Passes I easily road past a bunch of people on 700x40something knobbies (Riddlers, Raddlers, Ramblers, etc) pushing their bikes. Being on the tall end 26" wheels look undersized on my bikes so I abandoned that experiment, but my conclusion these days is just “run the biggest wheel that isn’t annoying”.
I have a set of i45 650b carbon plus rims and a pair of the G-One Speeds in 650 x 65 that I can run on my current bike in place of the 29x2.2 race kings. I’m interested to see how that works out, and if it comes down more to if they handle funky that if they’re fast/slow.
For sure. TBH a gravel bike with XS/S sizes designed around 650 and the rest around 700 (with correspondingly longer chain stays and other geo tweaks) would make a ton of sense. To some degree I think the need to source additional parts for complete builds (e.g. different wheels, tires, a second fork etc.) has made this a rarer solution.
Agree totally. I’ve been impressed with Canyon’s approach to sizing in this way. I’ve never bought or ridden one, but the principle feels right.
I think this is a great point. I’m not sure when 650b wheels make sense also for road bikes, whether you should place the cutoff at XS or XXS, but I think we would benefit from more diversity.
Bike size and having just one size are strong factors that make 700c wheels more attractive. (Although neither has anything to do with rolling resistance or roll-over capability.) Probably the latter is a very strong driving force towards 700c wheelsets.
Two “gravel” (really mtb) trends: 1X drivetrains and “forward geometry” via slacker head tube angles, larger fork offsets, and shorter stems makes bigger wheels easier to design around in the smaller sizes. Some things, like taller stack heights, can’t be solved, but aren’t problems for a good fraction of the market anyway. Though of course that’s been the industry’s “solution” for small bike geometry for a good 50 years anyway, so I guess everything old is new again…
In a pavement context I find these longer front centers don’t handle as well and even on dirt the standing-position bias and need for weight shifts interrupts your delivery of seated power (if that’s what you’re interested in doing).
I find that the handling just requires a different style, I definitely prefer it, though I’m not on the extreme end of gravel. 1050-1060 wheelbases still work well on all surfaces for me in a 58
Trek introducing today the new Checkpoint and Checkmate. Again, another brand giving the “adventure” model, the Checkpoint more tire clearance (50mm) than the race model, the Checkmate with 45mm.
These bikes most likely have been in industrialization phase for quite a while, way before this current wave of 2.2 tires on gravel bikes. Must be quite a frustrating time to be a Product Manager at some brands
Yes, limiting tire clearance on the “race” bike seems like a miss from Trek.
Who makes a race-ish gravel bike with 50mm+ tire clearance, downtube storage, and UDH compatibility? It seems like a really short list. I expect these features to become pretty standard, but maybe we need to wait another generation.
The updated Revolt seems great, but lack of UDH feels like a huge miss given new SRAM 1x13 (and expectation of this to trickle down to Force and Rival soon.)
MOG, New Stigmata….Is that it?
Don’t think downtime storage is super important so if you rule that out I think it’s also fair to include Felt and Lauf. And sounds like Allied soon.
Revolt would be right there, but with the flip chip, no udh. 53mm in the long position
Yeah. Who racing wants to sit there and pull out stuff from the down tube and pack it all up when you are done? It is better alternative than a saddle bag? Just seems like something that can loosen up and rattle. Personally would never use it.
I have to wonder if Giant will do a running change to add a UDH in place of the flip chip.
Re: DT storage, I ride in the PNW where seat bags often end up covered in mud and zippers die due to grit ingress. I rarely need flat repair stuff, but keeping it in the DT is both literally and figuratively cleaner than in a seat bag IME.
