[Closed] What size wheel? Hopefully this will end it.......

A few points:

First, the results haven't been published yet and we are reacting to one tweet. The first rule of any research study is "check who funded it". Santa Cruz may not have interfered with the study in any way, but if their lawyers are on the ball they'll have a clause allowing them to block publication of any results that could be detrimental to their business.

Second, they didn't test wheels (of course) they tested bikes. Getting the geometry just right for each wheelsize takes time. If the 650B is slowest then it could just mean that Santa Cruz haven't quite sorted the 650B geometry yet.

Of course a double blinded study is the ideal, but if you can't do one then you have to do what you can and just take the limitations of the study into account when interpreting the results. Sticking a needle in your eye isn't the best way to probe the function of the optic nerve, but it did give Newton a few useful clues.

Finally, the second rule of research is "check where the results are published". Have they appeared in a well respected journal having gone through a rigorous peer review process or are they in a YouTube video. I doubt the guy doing it really thinks this is science, but it's a bit of fun

As many of us have been saying all along, there are clear benefits for different types of riding in choosing 26" or 29" wheels, and they are different enough to happily co-exist, but choosing 650B as a middle wheelsize doesn't necessarily give you the best of both worlds, it may in fact give you the all the drawbacks of the other two wheelsizes (i.e. slower to accelerate due to the extra weight over 26" but without the extra rollover and stability of 29"). It sounds like this study might back-up that theory.

Caveat: I have never ridden a 650B but own 26", 29" and fat wheeled bikes so their may be a hint of bias. Other advice and points of view are available 😉

I'm going to suggest that the issue with all these studies, is that for the "average" case, the effect of wheelsize is insignificant (Statistically) compared to the other "noise" factors in the test.

In extremis, wheelsize clearly makes a difference, with a 29er being unsuitable to WC downhill racings, and a 26er being slower over 10 day adventure marathon course etc. But in the middle, the sort of riding most people do, the differences are tiny. Measurable, but tiny, and easily swamped by a million other factors.

For these tests, the only currently quoted figure is "14sec in 3.8km", which, assuming an average speed of say 20kph is 14sec in 684sec, which is 2% faster. To be 95% confident of a 2% improvement, we have to know the standard deviation of the results over enough runs to form that confidence. As yet, we don't know if that was done for these tests.

And, even if it was, and 2% is the answer, for You, or I, or Joe Blogs, if you're not actually RACING, who cares? 2% is nothing!

And, even if it was, and 2% is the answer, for You, or I, or Joe Blogs, if you're not actually RACING, who cares? 2% is nothing!

So we should all ride fat bikes and have more fun 😀

Listen guys if you want the definitive facts ignore the so called boffins. These are my findings.

650b felt the same as 26.
29 was well faster, and therefore more fun.

My study was self-funded, and hereby published in STW the only MTB publication of any import.

I suspect its about to be strenuously peer-reviewed.

a 29er being unsuitable to WC downhill racings

Nonsense. Wheel tech has moved on to the point where strong enough 29 wheels are possible, for sure, and that was probably the only “real” reason not to have DH 29ers. That and market segmentation/image. And tyre choice. The same reasons inbetweener DH bikes took a while to happen all hold true. Doesn't mean 29er DH bikes couldn't be made to work. But why bother? Adding extra wheelsizes adds nothing to the spectacle or competition really.

650b felt the same as 26.
29 was well faster, and therefore more fun.

Agreed on all but the fun… I'm sure you can make a bike overloaded with the ability to be fun with any wheelsize… and that's about more than going fast, for most if us, I'd hope.

So we should all ride fat bikes and have more fun

They're not laughing with you, they are laughing at you

Finally, the second rule of research is "check where the results are published". Have they appeared in a well respected journal having gone through a rigorous peer review process or are they in a YouTube video. I doubt the guy doing it really thinks this is science, but it's a bit of fun

From Dr Hurst
"We are hoping to get the findings published in the Journal of Sports Science and the manuscripts are currently in the final stage of review, so hopefully they will be out in the next few months."

This is actually quite farcical, embarrassingly so. The 'research' is a joke and the results are essentially meaningless.

The tweet about the the results seems to be missing/deleted. Anyone snapshot it before it disapeared?

I'm curious if they have evidence that 29 was faster [i]and[/i] less effort than 26. Having both (albeit on very different bikes to fairly compare) I feel fastest on the one I have recently been riding on the most.

Looking forward to reading the article in the journal, but I doubt it will bear much relation to what's been written so far.

Part 2:

What a joke. They could have arrived at a very similar conclusion with a stopwatch 😀

EDIT. Anyway, hasn't the proverbial horse well and truly bolted already on this topic?

It's not really cleared anything up! It would have been more useful to have had more riders (but still at a similar level) but going over more types of terrain, bigger ups and downs and longer circuits - same test on multiple routes. It's clear on one thing though (what everyone probably knows anyway), that rider and fitness is the biggest performance factor.

I'm really quite annoyed by that. As a scientist you don't state that the results are not statistically significant then spend ten minutes talking as if they were. That's just misleading. This study wasn't sufficiently powered to produce a significant result. So go do another study that is. Anything else is just bad science.

original article seems to have gone as well ?
http://www.bikeradar.com/mtb/gear/article/how-does-mountain-bike-wheel-size-really-affect-performance-43481/

Can't help but think that 27.5 bike was slow because it looked shit. the 26er and 29er had nice paint jobs and stickers.

650B is the slowest up and down... TeeHee 😆

The latest thing isn't always better than what's out there already however much the trail comes alive 😉

On descriptive statistics i.e. average speed, 29er was faster on that course on that day.
For a proper statistical analysis they need more riders. The population was too small to have much statistical power, therefore the effect size needed to be really good to get a significant result. But there's an approach toward significance which may well be validated by a larger sample size.
Make of it what you will. I'll stick to racing and riding on a 29er.

So go do another study that is.

Yawns....

roverpig - Member
I'm really quite annoyed by that. As a scientist you don't state that the results are not statistically significant then spend ten minutes talking as if they were. That's just misleading. This study wasn't sufficiently powered to produce a significant result. So go do another study that is. Anything else is just bad science.

+1

you may as well just get the daily mail to run a feature on it

What we need is another test................really
29ers are faster them's the facts.

Surely it depends on the course. Fast and open = 29, tight and twisty = 26?

Yeah, surely no statistically significant difference is just that,

Dissapointed they didn't break it down further than time, they intimated 29 used less energy but not how many less calories or anything, clearly not enough to show a significant difference.

The best and fittest rider will always be the fastest... Fact.

But I do find it amusing that the "magic there can be only one" in-between wheel size was the slowest by a not insignificant margin. New and shiny isn't always best eh?

Dissapointed they didn't break it down further than time, they intimated 29 used less energy but not how many less calories or anything, clearly not enough to show a significant difference.

This I is what I was hoping for. How many calories does each bike need to get it around the course in say 10 minutes.

I'm getting a new bike soon, bottom line is the make I want don't make 26 anymore and I don't fancy a 29 so 650b it is - I'm totally unfussed, things change and that's that.

'm really quite annoyed by that. As a scientist you don't state that the results are not statistically significant then spend ten minutes talking as if they were. That's just misleading. This study wasn't sufficiently powered to produce a significant result. So go do another study that is. Anything else is just bad science.

Not really no.
Statistical significance is an artifice, and without knowing what threshold has been set you're not in a position to comment on the validity of the results. Let's say they've set a 5% level threshold and their dataset comes of with a 5.5% probability of being incorrect - whilst not then meeting the required significance, it's still pretty likely to hold true. And of course had they set a threshold of 6% then their results would count as statistically significant.
Sport science is one of those areas where the results are rarely statistically significant to typically used significance levels because the datasets are typically too small. That doesn't mean the results are invalid though.
The problem is not with the science, or scientists, but with people not understanding what statistically significant means.
Bit like when people say evolution is only a theory.

But they didn't try a 27plus that would obviously have beaten them all! 😈

I'll wait to read the paper and if his p value is 0.06 or something I'll let him off. Heck I'd accept a 90% confidence for this type of study. But to say that the results are not scientifically significant then try to claim some kind of "practical" significance and to talk about differences of 12sec as if that was absolute (with no mention of errors) bugs me.

Don't get me wrong, I'm no fan of the compromise wheel size and these results suit me just fine. But I don't think they do much to improve the public understanding of science.

Surely it depends on the course. Fast and open = 29, tight and twisty = 26?

I was really suprised that in a straight line it felt slower than my 26" and seemed to take more effort to get it going up to speed. Maybe it was just that particular 29'er but I was expecting to be blown away by it's straight line speed but it just felt like a tank.

I'll wait to read the paper and if his p value is 0.06 or something I'll let him off. Heck I'd accept a 90% confidence for this type of study. But to say that the results are not scientifically significant then try to claim some kind of "practical" significance and to talk about differences of 12sec as if that was absolute (with no mention of errors) bugs me.

Don't get me wrong, I'm no fan of the compromise wheel size and these results suit me just fine. But I don't think they do much to improve the public understanding of science.

Yup, I agree entirely.
BTW I recognised one of those researchers in that video. I think he might still be an STW member, so you there's an outside possibility that you might get an answer straight from the horse's mouth 🙂

Wanna know whats the fastest bike for the type of riding you do? Check out what the pros ride.

Listen, this is all well and good but which is the best for sweet jumps?

edit- schralp that gnar STW!

I didn't think it was particularly good science and the results are fairly odd too but its a good piece to get people to the website

If that's “science” we're better off with people just riding bikes and then telling us what they think.

Its never going to be a fair test until the testees ride 26, 27, 29 blindfolded.

Its never going to be a fair test until the testees ride 26, 27, 29 blindfolded.

I've always relied on the intuition of my testicles 😛

I thought this interview with Curtis Keene said more about wheel size than this incompetent 'analysis':

http://www.mtb-mag.com/en/interview-curtis-keene-speaks-on-racing-his-career-and-more/

29 faster on some tracks, 27.5 on others. And by logical extension, 26 would be on tighter smoother tracks (but do they ride them in the EWS?)

I think a really perfect 26 would be quickest on my local trails, despite my 27.5 full-sus being much faster than my 26 hardtail.

slackalice - Member

I've always relied on the intuition of my testicles

I [i]knew[/i] that word was familiar when I wrote it....

The scenario 'your 29er has a goosed rear hub , you go out on your obsolete 26" , ride for 10 hours and clock up 50-60 miles over awesome singletrack etc {grinning from ear to ear] , then and get home think ' well that was shit having to ride a obsolete 26" ' ? .

BTW how can anyone mention what pro's ride ? they get paid to ride what the manufacturer/sponsor give's them . £££££££

So if 29"wheels are noticeably faster as the guy said and as everybody with 29ers claim,will they have their own category in competitions,I know it's all down to rider choice but if they are faster then obviously it's an unfair race,iff not then please explain?

The only thing this study proved was that the measurements are far too unreliable to be useful with small differences in speed, and a limited number of observations. I suggest repeating with 50 laps (According to my very inaccurate power calculation) on each bike and then come back if you actually want statistically useful results. Or, just forget the stats and present the raw data.

To be fair, I respect the valiant effort they've gone to, but I think they've drawn far too many conclusions from their limited data.

It also looked as though they might be doing some sort of VO2 measurement at various stages, which would be a great way to 'control' for levels of exertion and energy usage. I didn't see any mention of that in the video though.

BTW how can anyone mention what pro's ride ? they get paid to ride what the manufacturer/sponsor give's them . £££££££

Really? Think you'll find the top guys work with their sponsors on building / designing the fastest bikes.