[Closed] Any scientific studies on lap times with different wheel sizes?

You'd think there would be something published seeing as most manufacturers claim to have "done the research" and "have the data" before deciding to ditching 26". Probably just mean market research 🙂

Has there been any real scientific studies with riders on a course recording lap times on different wheel sizes? If so could you post a link?

Don't be daft, that would prove what most of us already know, wheel size makes bugger all difference.

Has there been any real scientific studies with riders on a course recording lap times on different wheel sizes? If so could you post a link?

Just spent a few moments seeking this one out - closest I've seen to what you describe:

Just watch the Olympic mtb final and see what the winner was using. If you're slower than him you can be sure it's not wheel size that's the problem.

Don't be daft, that would prove what most of us already know, wheel size makes bugger all difference.

Yeah right 😆

Every trip round the countryside is a race.

To be scientific, it needs to be a double blind test. Would love to see that 🙂

And lots of riders riding lots of bikes lots over lots of different courses and terrains, and doing stats on all the results.

each size has pros and cons, basically no wheel is faster, just faster in one situation.

Yeah right

Get back under your bridge.

That video- he precedes the "scientific" test by saying he's going to find out just how much quicker the 29er is.
He then goes out and proves that is just over 4% quicker.
Make of that what you will. Not science though

And another kitten dies a painful death.

each size has pros and cons, basically no wheel is faster, just faster in one situation.

Yeah but a certain size is faster in more situations than other sizes 😆

A magazine test was quoted and linked to on a recent 29er thread, there was only some data though, not all of it.

It's pretty much an impossible challenge- because you can't change wheel size without changing a stack of other factors, so there's no way to isolate it. (so for example you get boneheaded MBR commentary on how amazing 650b is because it works so well in the completely different new Orange Five compared to the old 26 inch one). But even if you could isolate it, that'd still not be a fair comparison because you'd end up with a basic spec that favoured one wheel size or another- so frexample convertible bikes, which were designed for 26 inch but now have adaptors to take 650b.

So what you're left with is a lot of new model vs old model comparisons, and no surprise, new models are often better, and almost all the new models are 29 or 650b with most being 650b right now. So the best you can hope for is comparisons between either broadly similiar bikes, or the best you can do in each wheel size.

But even then, since there's no such thing as a best bike, everyone'll probably end up going fastest on the bike that suits them best not the bike that is best.

Still there's been some good attempts, the mad scientist Nico Vouilloz tested 26 vs 650b and decided to his satisfaction that 650b is fractionally faster. This is a guy who spent hours machining down and testing different maxles to see which has the preferred amount of flex, after discovering Lapierre had made their bikes too stiff, so marketing aside I reckon if he says it's better for him, it is. But that's only 2 sizes.

I read about one in either Singletrack or MBR, but to be honest the times between different wheel sizes were pretty similar, something like 20 sec in a lap of about 14 mins, so depends if you're after a podium spot or not.

If you really mean scientific, then no. I've never seen anything, in print or online, that would stand a snowball's chance in hell of getting published in a decent peer reviewer journal.

It's interesting to consider whether a scientific test of a bike is even possible. I suspect (for the reasons already outlined by Northwind and andytherocketeer) that it probably isn't.

People will moan that they don't reflect real life, but I'd like to see a lot more lab testing of isolated components though. How about a test of the three wheels (in an identical rigid fork) on a bumpy rolling road. Then you could look at the power required to maintain certain speeds with each wheel size and look at how that varies with, for example, tyre pressure. It wouldn't be a "real world" test, but it would show whether any differences were bigger than the natural variance that you would see in day-to-day riding.

I'd be interested in both your comments on the test I referred to - I'll try to find the thread.

I upset a few people by questioning how scientific it was.

And people question hi fi magazine claims...

Do people who don't think wheel size makes any difference also think head and seat angles make no difference?

JCL nobody is saying it makes no difference just it's hard to tell in many ways. The change in wheel size also leads to other changes like angles.

The nico test was a great example where the difference was down there in the margins of error but people still extrapolated it to make it seem like he could have finished a round the world trip 5 weeks faster.

I have no issues with the fact that some bikes with some wheel sizes do some things better. Though to say it's all about wheel size is a little ambitious. But I'm sure you will be back to tell us Chris Froome should be doing the tdf on an enduro 29

The nico test was a great example where the difference was down there in the margins of error but people still extrapolated it to make it seem like he could have finished a round the world trip 5 weeks faster.

The test Nico did was between 26" and 650b. The difference there is marginal as we know.

Anyway I think what I asked is a valid question.

Worth noting that any off road back to back comparison can never really be a back to back comparison.

Unless of course you can guarantee that the rider will hit every bump at exactly the same angle, have their weight on the suspension in exactly the same way at the same points, etc. Way too many potential variables.

In short, try some bikes. See what feels best/fastest/nic(h)est for you, then buy it.

Before I bought a 29'er for racing duties I did some timed laps with a hrm of a route to see if they were faster.
So, similar weight bike, just 26" vrs 29" wheel. Xc course, no big drop offs or things. (Whinlatter north loop)
I rode my 'race' bike around the course then did it again on the 29'er with a similar heart rate. I was 3 mins quicker on the 29'er. I then thought I could of been over excite able on the 29'er so I rode out and about for 2hrs before returning to do the test again. The second time I was 1min quicker on the 29'er.
This WAS NOT scientific or controlled but I just wanted to see. Since then I sold the 26'er and got a 29'er.
For me and what I do I find them quicker, however, they are not as nimble.

Horses for courses.

What CFH said ^^.

There's no way it can be scientific cos you can never replicate an exact lap. Same power, same effort, same lines, same weather conditions is almost impossible. Not to mention any inherent bias of the rider - maybe just easing up a touch here or trying a bit harder there in order to rig the result.

Some magazine (MBR??) did some timed laps of Mountain Mayhem one year on FS vs HT by having a load of hire bikes which were as near identical as possible other then the rear suspension. They found that FS was faster although predictably at the time, MBR was convinced that the only way anyone could ride off road was on a 6" travel FS...

Second time around... better warmed up, better line choice... etc. Too many variables.

I guess looking at the sharp end of competition (e.g. World Cup stuff) is a good indicator. Some wheel sizes are definitely more prevalent in different disciplines so some riders definitely think one is quicker than the other (though there are the obvious commercial factors.) Despite this there are riders, all of similar ability, on all different wheel sizes putting in competitive times and winning races. For example, in XC racing, while 29ers are currently dominant in terms of numbers, it's not like all 29ers finish way ahead of all 650B, finishing way ahead of the 26ers. It's nowhere near being that clear cut as far as I can see.

[img] [/img]

Drac, sorry, though i think I can be forgiven as this is the first wheel size thread I've ever posted on!

Here we go. Don't say the test in this thread isn't scientific though or some people will get upset!

http://singletrackworld.com/forum/topic/29er-for-xc-racing

I'm tempted to set one of these tests up myself when I get time.

I may just do that in the summer using multiple lap times from different days for both sizes and correlate power meter readings to try and show effort levels were consistent etc.

If there's no screamingly obvious difference, why would it matter to anyone except elite racers?

I've done loads of laps of local trails trying out stem lengths, tyres, different fork travel on a frame, etc etc. Never once have I thought of timing anything : ) It either feels better or worse. What else matters? If it feels right you'll probably either go a little quicker sometimes or be comfier. No science.. same for wheels. If there was any real science we've had about 10 years to do it. None so far. I don't believe there is any. There's some fairly simple mechanics and your preferences. If that doesn't answer it for you, be happy that you don't care!

stick 650b logos all over a 26er frame, wheels and tyres, and I bet the average STWer would probably get a different time to the identical bike with normal 26er logos.

and as I keep saying. every ride is a race.

And another kitten dies a painful death.

That test's a perfect example of why it's so difficult to do this- the weights of all the bikes are the same, which is automatically biasing towards larger wheels since if the spec was equivalent, the bigger wheeled bike would be heavier. 3 different bikes. Same tyres but that doesn't mean equivalent performance. None of these things are unreasonable of course but they make the test imperfect.

(another thing that makes the test imperfect is the wobbly results frankly)

How many people on here race regularly? For them I can see some sort of point to this debate. For everyone else, who gives a crap about whether one sort of bike might be a few seconds faster than another????

No, there is no scientific evidence and there never will be- too many variables and certainly not in the interest if manufactures when marketing alone is doing such a good job.

My thoughts from the thread Cynic-Al linked earlier

However, as Matt as acknowledged himself it isn't a perfect test. It is a good test but hard to draw any real conclusions besides the small amount of data providing some evidence for one user that the 29er appears to be the faster bike and certainly not any slower than the 26er or 650B on the one course tested. To say it is scientific though isn't really too accurate though IMO. I don't claim that a "scientific" test is easy though so I am certainly not intending to criticize and couldn't do better myself!

The small number of observations is an issue. Day to day variability usually requires repeat tests across 3-5 different days for most applications. Inter-subject variability? Again, 10 people would be the absolute bare minimum for anything like this to be published usually but some quick calculations based on the data might require a far higher number of testers are required. An interesting question is do 29ers yield advantages for all? Are 29ers advantageous across all courses? You can keep the mean power output the same between repeat tests but is the total power delivered equally in the same magnitudes and at the same times between repeat tests throughout the duration of a lap? Are the lines taken each lap and the energy used descending (almost impossible to measure!) consistent? You'd imagine a skilled racer can control this pretty well but something like Principal Component Analysis could identify areas of highest variance between power and HR waveforms of multiple laps then use PC scores to determine if there is statistically significant differences in how the mean power (or HR) is applied across the lap. The tester was also not blind to the bike being used so may bias the results. A placebo 29er would be an interesting test too If the bikes were of equal weight overall then the rotational masses and distribution of weight would presumably be different between the bikes. How do you go about making the bikes "identical"??? You could go on and on!

The test may not be scientific but the reality I think is that there are too many variables to control or account for to actually conduct a "proper" scientific test. Anyone who tried would leave themselves open to criticism one way or another and lets be honest it isn't in the interest of manufacturers when the easiest solution is to just make all bike in one wheel size and force the change Experienced racers certainly don't seem hindered by 29ers. All I know is Matt could ride a BMX and beat me on the pimpest whatever bike on any course

Science and wheel size? That's like matter and anti-matter - can't be combined into anything. Except possibly an earth-obliterating explosion

If you have two bike on a tread mill wit the same gearing, a 26 and 29 get a robot to turn the pedals at the same power output and time. Would one bike go further than the other?

Obviously other factors involved like quicker turning for 26, and smoothing out bumps for 29 etc. But surely the math geeks among you could figure out those.

My examples are crude as im not a scientist. But surely if there is a difference then these thing can be narrowed down to a few simple tests to prove where the majority of speed actually comes from?

PS I don't actually care about the answer. But I just strikes me that claims that it is immeasurable seem unlikely.

How many people on here race regularly? For them I can see some sort of point to this debate. For everyone else, who gives a crap about whether one sort of bike might be a few seconds faster than another????

I agree.

I only currently have a 29" but I have a friend that's faster who has comparable 26" and 29" bikes (actually the 26" is over two pounds lighter) If he rides the 26" I"m on his ass, if he rides the 29" he's gone. We've repeated it countless times on different courses and it's always the same.

Seosamh77: your robot leg test is do full of failure it's not true.

It would prove nothing that simple sums with rolling radii and gear calculations wouldn't predict with 100% accuracy.

It would not in any way show that one of two (three? More?) different bikes ridden at the limit of rider skill and endurance would always be faster everywhere, every time or even same place/time as it's just not possible. By the time you've standardised the variations out you're left with a 'test' so meaningless as to be 'I like this one better'.

And that's fine. But please don't try to call it scientific. An average person with no particularly good skill or fitness levels would probably find the larger wheel size flattered their efforts by moving faster for less effort and not getting anywhere near any situation where the considerations of vehicle size meant a smaller bike could be faster. That's not science, it's product marketing. Personally I ride because it's fun and I enjoy it. The bike industry keeps trying to sell me things it promises will make me faster and enhance my fun. As with the n-thousand pound gramme scrimping carbon roadie, the rider is cheaper to improve. I've seen 26ers moving faster than I can make them go. Once I've achieved that level, maybe new wheel sizes will be relevant to me... unless I wear a bike out or go mad before then... 🙂

JLC- Ever thought the 29er is faster as it has essentially got higher gearing if it is the same? Anyway asking which is faster is all wrong for a lot of people. The real question is which is more fun and luckily the answer is all of them depending on what you are doing.

The real question is which is more fun and luckily the answer is all of them depending on what you are doing.

Here here!

Now can we stop this kitten killing spree?

My original question was has anyone done a scientific experiment and could you link to it... not can we re-visit the merit's of fun vs marketing vs marginal gains again.

Thanks to those who have answered what I asked. The response about vs a mate who has two bikes is interesting and what sparked me to ask as I have a mate who I ride with regularly who has moved to a 29er and suddenly seems a fair bit fitter than before.

On the flat/rolling stuff it's probably faster but thats the bit where it's more noticeable. The missus went to a Tallboy from a Blur LTc which is 2kg lighter and shorter travel so apples and oranges really. She does motor on up the hills and on the smooth these days but not on the tech so much.

But you cannot do a scientific study as faster in one area may mean slower in another.

Take the example of skis. There are loads of different types and the ones that are fastest for Olympic downhill skiing would not be great or fun for most people or fastest in all conditions.

Tyre pressure has more influence than wheel size in my opinion. (Speaking from experience after pumping my 29er tyres up too hard this morning and being pinged all over the place.)

It would not in any way show that one of two (three? More?) different bikes ridden at the limit of rider skill and endurance would always be faster everywhere, every time or even same place/time as it's just not possible. By the time you've standardised the variations out you're left with a 'test' so meaningless as to be 'I like this one better'.

Think this is why it's useful to look at top level of competition. You have a lot of rides who are evenly matched in terms of ability. And you have the best bike available, whatever the wheel size, optimally set up for each rider. And in that arena (be it DH, XC or Enduro) all wheel sizes can get competitive times, and no one wheel size is dominant over the other in terms of lap/run times.

Scott (beware of marketing!) has a wheel size matters thing up at the mo, effectively saying that 650 are quicker over courses requiring a lot of stop/start and acceleration, 29ers are faster over smoother courses. Surprisingly unbiased compared to other brands.

http://wheelsizematters.scott-sports.com

mrblobby - Member

Think this is why it's useful to look at top level of competition. You have a lot of rides who are evenly matched in terms of ability. And you have the best bike available, whatever the wheel size, optimally set up for each rider.

Really? I don't think any of that is true tbh

Interesting that the Scott stuff doesn't say that Nico Schurter is riding 650b because he's tiny and couldn't get on with 29ers. Though it does say Geoff goes for 29ers because he's taller. So optimal wheel size determined by rider size...?

Edit...

Really? I don't think any of that is true tbh

How so?

So optimal wheel size determined by rider size...?

There was an interview with the Scott WC team manager(?) during the olympic (or might have been a WC) XC where this was the conclusion he said they'd come to from their testing, and that this was why nino was on 650b - it suited him and his physique best.

From a personal point of view, I bought a cheap 29er to try out and liked it. So replaced by 26" enduro bike too, and liked that new bike too. I am tall tho, but find them more fun. No idea if they're any faster, feel easier to ride in some situations, which may or may not make them faster...

theres a funny dirt article somewhere where they tell you 29ers are faster and go on to detail a test where they seem to be slower

here it is

http://dirtmag.co.uk/news/dirt-magazine-26v29-bonus-feature.html

There was an interview with the Scott WC team manager(?) during the olympic (or might have been a WC) XC where this was the conclusion he said they'd come to from their testing, and that this was why nino was on 650b - it suited him and his physique best.

Yet you see some tiny riders on 29ers. Emily Batty comes to mind.

I can't see how performance in wheel size as the OP suggests can be measured on anything other than road, as there are so many variables on the dirt. To say my mate is quicker on such a wheel size and slower on others, only proves that he prefers a certain type.

Masses of variables to make it in any way accurate to calculate. Faster in one way and slower in another is my opinion of all wheel sizes. Choose one that suits your riding preference, or multiples if you're fortunate enough to afford them.

I ride 26 on the dirt, because I'm 5'8" for a start, and more importantly perhaps, is that I love tight, super tight twisty single track. Gravity singeltrack and open descending yep, bigger wheels do seem more capable from what I've observed.

@mrblobby- why assume that all the top riders are equal? That seems incredibly unlikely. And they won't all be on the "best bike" unless all the bikes are also equal. In reality they're riding the best bike their sponsor offers them which isn't the same thing, and is also no guarantee that it suits them (see: aaron gwin). And for the same reason the setup isn't going to be optimum for everyone.

effectively saying that 650 are quicker over courses requiring a lot of stop/start and acceleration, 29ers are faster over smoother courses. Surprisingly unbiased compared to other brands.

@mrblobby- why assume that all the top riders are equal? That seems incredibly unlikely.

To ride at that level I think the top riders are all fairly equal (I'm thinking top 20 in a World Cup for example.) Even when you get one rider dominating, he's still only fractionally better than the rest of the field (and all are way better than your average rider.)

When you see some of the "tests" claiming that one wheel size is over a minute quicker over some 20 minute course than another wheel size, about 5% quicker. If that really was all consistently down to wheel size then you would get two (or three) speed races as that is a massive step, bigger I think than the gap between riders abilities.

Sponsored riders ride what they have to. I know of some female sponsored riders, 5'3"-5'4" and they were given 29ers because that's what the brand were marketing.

Just to play devils advocate (I'm a 650 fanboy) Nino rides a 29er for marathon racing, and Emily Batty rides for Trek (who don't do 650). Top riders tend to ride what they are paid to ride/whatever their sponsors are pushing that year.

And Emily looks shoehorned onto a 29er, she rides a -17 stem with no headset topcap. Its daft.

... and whatever they end up riding, they are still competitive against their peers.

It's good to have a choice, remember those "lamp-post" seat posts that taller riders used to have on their 26ers. But I don't think wheel size should become a universal standard.

Like head tubes, how many variants do we have, do we need bigger, how many busted head tubes have you seen on xc/cx/road bikes for example! ?

Even on her tippy toes its too big for her.

[img] [/img]

She'll need some pipe lagging on the top tube to prevent minge strike

[did I really say that]

It's impossible - too many variables and anyone who says they can prove wheelsize makes a definitive difference to how fast you can ride is basically lying. You can believe it if you want, but it's impossible to prove it.

How quick a bike goes down a given trail has more to do with rider skill than anything else... some days I'll ride a trail faster than other days - depends how fit I am and how smoothly I'm riding...

One thing that stands out for me is that there is never any mention of comparing wheel sizes but with the same contact patch area. For example, I've not seen any test where they've said,

"We compared a 29er with a 2.1" tyre, a 650b with a 2.3" tyre, and a 26" with a 2.5" tyre. These sizes allowed us to run the tyres at the same pressures and maintain the same contact patch area."*

Seems to me that if you don't even bother to maintain the contact patch size then any like with like test is going to be completely meaningless.

*I know these sizes probably won't result in the same contact patch size, if you can be bothered doing the maths to get the right numbers then knock yourself out 🙂

Edit: My experimentation with a 3" tyre on a 24" rim on the back of my Nomad continues. The only conclusion I can draw so far is I'm having fun 🙂

For many of us although speed is a factor there are other things that come into play too . It's great if you can ride up , down , through or over stuff that your riding buddies can't . For me , who is by no means a riding God , I find that I can do all these things better on a 29" bike . I have never ridden a 650B but having gone from 26 to 29 and noticed big improvements I can't see how going back down to 650b , which is pretty close to 26" could possibly be better .

One thing that stands out for me is that there is never any mention of comparing wheel sizes but with the same contact patch area. For example, I've not seen any test where they've said,

Think like for like test is pretty pointless as far as most are concerned. If the bike isn't set up how it's actually be ridden then what's the point? Compromising performance for some like for like setting doesn't tell you much if you want to know which is quicker out on the trails.

If we want to eliminate variables then maybe we should look to the world of unicycling as wheel size is a bigger factor there 🙂 and bigger is definitely better for trail riding!

mrblobby - Member

To ride at that level I think the top riders are all fairly equal (I'm thinking top 20 in a World Cup for example.) Even when you get one rider dominating, he's still only fractionally better than the rest of the field (and all are way better than your average rider.)

Yup, but they're not the same- by which I mean, one rider might be a stronger climber, another a better technician. So that'll all still play to the strengths and weaknesses of different bikes. And then, add in the personal taste factor, like in downhill your Leovs and Beaumonts liking harder suspension than most and you've got some massive skews. The human element's overriding here I reckon.

Somebody (like, say, stw ?) could organise a semi-objective test, maybe at one of the 24hr race sites or their own weekender thing.

Chainless race from a standing start down a couple of different routes (one fairly smooth but needing cornering speed and the other nice and rough). Take a selection of "largely" comparable bikes with different wheelsizes and let anyone do timed runs, as many as they like, offering a small prize for fastest 26, 650 and 29 down each run. At the end, make everyone vote for the bikes they liked best as well, to cover the subjective fun bit

You could repeat the same format back up the hill on the next day if you wanted (err, with chains on, I guess)

The aggregated data could be posted on here for a stw excel-off afterwards 😀

Robin at Enduro Mag recently did a test of 3 wheel size variants of the same bike:

http://enduro-mtb.com/en/biketest-commencal-meta-3-wheel-sizes-compared/

Review came back that each was a bit faster in certain situations, but overall, he felt the 650B version was the best all rounder of the 3 variants, when speed, control, fun factor were all considered. But essentially, it's not that clear cut.

As far as I know, this is the only test of it's type I have seen in the press.

🙂

... and whatever they end up riding, they are still competitive against their peers.

It is almost as though differences in training and physiology play a bigger role in racing than the differences between high end tools provided by sponsors from different brands 😕 😆

A minute gained on a 20 minute lap might sound great (who wouldn't take that!) but 5% error is within the measurement error of devices used to try and measure comparative differences of wheel sizes (power output for example) not to mention variation is all the other factors already discussed.

Still, I'd love to see the results of a 29er vs a placebo 29er (26er in disguise!) 😀

As far as I know, this is the only test of it's type I have seen in the press.

It's the only review (note "review", not "test", cos there's nothing testing about it in a scientific way), where one of the reviewers dared to say that 650b inherits the compromises of 26+29. Of course 99.9999999% of all 650b BS will only ever mention that you get the best of both worlds.

Except in MBR where they've already decided the outcome before even stepping on the bike, based entirely on wheel size and whether the brakes are Avid Elixir,and whether the tyres are Nobby Nic.

whether the tyres are Nobby Nic

not IME

Oh forgot bar width. Knock off 1 point out of 10 for every 1cm shorter than the longest bar width they've ever had in to review.

You forgot to mention the performance-enhancement of an Orange headtube badge 😉

heres another
http://www.mbaction.com/Main/News/Shootout-Wheel-Wars-29-vs-275-vs-26-5159.aspx

I saw this in their mag in 2012 back when stw didnt have a weekly 3-way wheelsize smackdown I think it was the first proper mention id heard of 650b

"We compared a 29er with a 2.1" tyre, a 650b with a 2.3" tyre, and a 26" with a 2.5" tyre. These sizes allowed us to run the tyres at the same pressures and maintain the same contact patch area."*

The difference really isn't that big:

http://bansheebikes.blogspot.co.uk/2013/11/wheel-size-facts-part-3-contact-patch.html