It's clearly something you want. Do many other people care about it?

They might have been developed anyway. Time trial bikes (via things like the Ironman) have independent avenues for technological advancement (more than the TdF).

None of this seems that good of a reason.

Not the bike. It's the motor.

Those folks would have placed the same on 700c tires as well.

I don't think there is any way to prove or disprove this theory. What it does show is the viability of the bigger wheels. Certainly you agree that wheel size can make a difference? Would they have gone as fast on 14 inch wheels? Would 14 inch wheels work as well in rocky terrain? Of course not.

If people didn't experiment with different wheel sizes we wouldn't have any way of knowing what works or what the limits are. I'm all for innovation and choices. Would I buy a 32 inch bike now? No, but I'm open to hearing more about them and seeing their results.

Of course, the motor is always a huge factor. But in off-road racing, a certain minimum capability is a factor, as well. You wouldn't take a cross country race bike to a downhill race, or vice versa.
You have said how nice your 29er works. Those bikes were developed with r&d and trying different geometry and wheel size. Is it the end of the road? Will there never be further improvement?

Run the same course back-to-back some number of times and see if there's a trend showing one is faster?

I don't think anybody doubted that 32 inch wheels would work (not much differently than 29 inch wheels). Anyway,, they really have to be more than just "viable".

Certainly, you can agree that 14 inch wheels are more than 50% smaller and 32 inches is 10% larger than 29 inch wheels and that one would likely see a much larger difference with the 14 inch wheels. Certainly, there is no reason to expect that the benefit from going to 14 to 29 and 29 to 32 to have the same rate of improvement. Certainly, you can agree that there is going to be a fall-off of returns for ever-larger wheels.

??? If there isn't any way to "prove or disprove" it, how can you be "certain"?

I've said in the past, that I've thought 32" wheels were unnecessary for gravel, but part of me thinks that they might have a place. In gravel racing/riding, there are often parts of the course that you will either be over or under-biked. With my most recent gravel race, even my Lauf rigid with 29"er 2.2" XC tires was grossly under-biked on a certain part of that course. I can't say for sure, but I imagine a 32" wheel set up would be appreciably faster in that section.

The difference in wheel size between 700c and 32" isn't enough to make a difference or give them an advantage IMO. It's still the motor not the bike. He would probably have won on a different bike just like he has numerous other times. We are talking Elite racers here. Outside of Unbound he won all his races on 700c tires.

Robin Gemperle is an elite Swiss ultra-endurance cyclist. He has built a prolific winning record in some of the world's most grueling self-supported bikepacking races.

His notable victories include:

• 2026 Unbound Gravel XL: Won the 356.5-mile race in 21 hours, 20 minutes on a prototype 32-inch gravel bike.
• 2025 Tour Divide: Set a new course record of 11 days, 19 hours, and 14 minutes for the ~2,700-mile unsupported race.
• 2025 SRMR (Silk Road Mountain Race): Took 1st place in the demanding Kyrgyz Republic ultra-endurance event.
• 2024 Transcontinental Race (TCR No. 10): Won the roughly 4,000 km unsupported race across Europe to Istanbul in 8 days and 23 hours.
• 2023 Atlas Mountain Race: Claimed 1st place in the 1,145 km Moroccan bikepacking race.

https://bikepacking.com/news/robin-g...5-tour-divide/

https://www.apidura.com/journal/robi...TECiTGMNQC5biX

Running the same course would be tough because it would not be the same in a mud race. The riders might have an off day, how many 350 mile mud races could you duplicate the exact conditions? Collecting sufficient data would be a challenge.

Viability is just a starting point

Of course I agree with your points about the differences between 14, 29, and 32 sizes. I was just trying to illustrate a point that not every wheel size is equal. Just suggesting that there could be a difference by exaggerating the difference. I don't claim to have the answer about 32 or even 36 inch wheels.

And to your last point, the poster had said the racers who won or placed high in a long mud race would have gone the same speed with smaller wheels. This was what I was saying couldn't be proven either way. You couldn't duplicate the exact conditions of a 350 mile mud race. When I said "certainly" I was suggesting the poster consider all wheel sizes. Certainly you agree there can be differences between very small and very big wheels? How much between 29 and 32? Maybe not very much.

You're probably right on both points. But what if the 32" wheels saved a tiny bit of energy on the rough stuff? Over 350 miles that could add up.

Maybe it's not enough to add up to anything. Maybe the development of tires and wheels will make 32s better than they are. I don't know, but lots of people were skeptical of 29ers when they first came out. I know I was which was one reason I picked a 27.5 bike when I replaced my last 26er. I thought the jump to 29 might feel foreign after riding 26 for 30ish years.

just saw your edit: Yes, that guy is a beast. Ultra endurance athletes are their own breed. Maybe he could win on a 26er. At his level, nothing would surprise me.

No, it wouldn't be the same but it still might show a trend (which is why you'd have to do multiple runs). Not all things are mud races.

You don't have to do this. Certainly, there are more options than to do nothing.

It's nothing like enough. Has anybody claimed it wouldn't be viable?

Some people are claiming the 32 inch wheels mattered. It doesn't seem like you complained about that.

That's what I was saying: 32 isn't that different. The differences between "very small and very big wheels" doesn't seem relevant.

I haven't disagreed with you. I didn't "complain" about anyone saying the wheels didn't help. I said it would be tough to prove either way.

Obviously when a new product comes out it takes time to gather data, show trends, backup claims, etc. That was my point, just to not dismiss it outright.

Regardling 32" winning Unbound...it will be interesting to see how much buy-in there is for 32" gravel wheels and tires. Right now, 32" tires are all in traditionally MTB widths.
How much actual interest is there for a 45mm 32" gravel tire? How much adoption will be just sort of inevitable due to that is what some well regarded bikes are designed around, and that 'buy-in' then snowballs?

Geometry, at least on the smaller end, will be fascinating. Over on paceline, David Kirk has written about this and the design concerns/challenges are really interesting.
I am 6'5 and am not concerned about a 32" wheel gravel bike fitting me properly. But my youngest kid who is 5'3?...that seems like an issue, at least at first blush.

700C already compromises geometry for shorter people. That is, shorter people might be better off with smaller wheels. It seems the same thing would be the case for 32 inch wheels.

Some folks are trying to make the case for 32" being better for larger riders. I don't buy into it.

Make a frame to accommodate the 6'6"+ guy and it doesn't matter if you have 24, 26, 27.5 or 32" tires. Frame still fits the same.

Or back to 26"