I quite like that a 26 wheel and MTB tyre has the most similar diameter to a road wheel and road tyre.

It should actually be the other way around to the previous few posts if 29ers are really so much faster- Road companies should be increasing the wheel size.

Surely if bigger was faster during sustained higher speeds (rather than lots of short sharp accelerations- as appears to be one of the main arguments for increased MTB wheel sizes) then roadies have a lot to gain by increasing their wheel sizes.

I know toe overlap and so on are a limitation on a road bike but I’m sure frame builders would find a way around it if there was an advantage to bigger wheels. Much like the ridiculously angled stems pros are having to use on their 29ers because the huge wheels push the bars far too high for them! 😀

Sounds like this highly scientific test is based on…..errmmmm pretty much zero meaningful data?

Go back, compare exactly the same bike model with different wheel sizes. Use the same track climb it 5 times with each bike. Alternating which one you use. Use the same method of speed measurement on each, add a power meter and heart rate monitor too. Then keep a close eye on the weather to ensure that is remains the same for each run (we wouldn’t want colder more dense air slowing us down now.

Once you have done all of that, come back and we can all discuss the results (measure data) over a nice cup of tea.

The plural of anecdote is not data.

40 replies and no nearer an answer.
With all the resources and contacts STW have got, it shouldn’t be too hard to source two near identical bikes and two PowerTaps and do some testing. It would make an interesting magazine article.

It’s almost as if the magazines and manufacturers are colluding to avoid any scientific proof and keep the debate going.

or that the scientific data is not what the manufacturers want you to see.

The plural of anecdote is not data.

I like that

It’s almost as if the magazines and manufacturers are colluding to avoid any scientific proof and keep the debate going.

No, never, shock horror!

OK, we’re drifting off topic here, as expected. It’s probably pointless trying to bring it back, but just to be clear; I’m not trying to claim that my tests are scientific. Far from it. My own conclusion, in the absence of any proof to the contrary, is still that I’m going faster because I’m putting more effort in. I just wanted to open the question up to a wider audience to see if anybody could suggest an alternative hypothesis. Designing an experiment is easy enough. Designing one that can be carried out with the resources available is a bit harder. But in both cases it’s usually best to start with a hypothesis that you want to test.

The problem is that you want a hypothesis that is both testable and relevant. Unfortunately, with bikes, the hypotheses that are relevant (e.g. “29ers are better than 26″ bikes”) are too broad to be testable and the ones that are testable (e.g. various lab tests) are often not relevant.

needs an electric bike with matchable gearing for the 2 (3?) sizes. Rag the arse off it so it’s putting out max power at all points on a timed run and see how that goes

Ton’s got one hasn’t he ?

Its because 29ersof were designed for towpaths & fireroads are uphill towpaths. Anyway why are you testing 29ers & 26″ they are both obsolete now 27.5 is here

I’ve got a feeling that its not about the weight but the position of the weight relative to the centre

It’s only about weight. If the wheel is heavier it has more inertia, that’s all. As the wheel gets bigger it rotates slower so that cancels out. 29ers tend to have heavier wheels, but it’s not a rule so we can’t say a bigger wheel has more inertia. Roverpig’s right, the flywheel effect isn’t in itself the reason and he’s going faster due to putting in more effort or using his effort more efficiently. Bike ergonomics suiting a rider needs = faster man and machine combo.

Some riders mash bigger gears and some spin lower gears. Work done on a given climb may actually be the same, yet one pedalling habit may suit a heavier wheel rotating slower, one may suit a lighter wheel rotating faster – but then we’re into maths that boils my head even when the principle’s easy. I ride SS and seem to mash gears = I like my heavier 29″ wheels.

On the testing, I’ll bet my bike that whatever the scientific method and however accurate the test with powertaps and controlled effort, it’s only represent a fraction of riding situations and thf not be conclusive. It can’t take into account rider input that improve or limit flow, handling etc that’s all part of the riding mix, or account for the affect of those tiny differences in input or ‘smoother over the bumps’ fatigue effects over long rides. That all comes from rider perception and experience, imo that’s all this is ever about.

james makes a good point – from a previous post are you not one of the “small frames are more chuckable hora brigade ” ? things will work better when on a correct size bike :d

No, or at least not in this case. Both bikes are pretty much the same size. I even put my own bars on the Gyro as I didn’t get on with the lower flatter bars it came with, so riding position was as close as I could get it.

As well as bikes I ride Mountain unicycles and have 24″, 29″ and 36″ wheeled ones and the 36″ is the best climber of all of them, the big wheel has a massive fly wheel effect so rolls everything and doesn’t want to stop, also one pedal revolution gets me further forward so my cadence is the same (just harder work) so I get up the hill faster.

The “little” 29er is easier up the hill as the crank to wheel diameter ratio is bigger than on my 36er but due to the natural rythem I get into the cadence is the same so it is far slower, to match the speed of the climb I would have to be peadaling at a higher rpm so would be tired in a different way.

Unicycling is fun 😆

On my 26″ and 29″ Scandals I find exactly the same thing, 26er is easier (same 32/18 ratio on both) as lower geared and the 29er is faster but harder

on my regular 10 mile loop my 29er is almost 10 minutes faster (and so much nicer up the hills)

Steve-Austin – Member
Have you found you are more attractive to women when riding the 29er?

I find that I can roll over them more easily when they throw themselves in front of me

This needs to be tested in space.

I’ll call NASA.

Surely this is only relevant to anyone actually racing against another man?
I find the 29er thing odd considering that marginal gains on the flat and fireroads are or seem to be considered a bit mincy, but that’s just the way I perceive things.
Remember the whole XC race thing months ago, the consensus seemed to think that XC should be more gnarly and that riders with ‘Skilz’ should be rewarded over fitter faster riders.
This seem to be at odds with the huge support for 29ers and the reasons that make a 29er a better choice.
So I suppose it is horses for courses.
I got rid of my 29er ages ago. It was a great 24 hour machine, but it ‘felt’ slow and cumbersome on very fast tight twisty XC races and areas with similar terrain.
The increased speed the OP talks of on that fire road, well I can find gains when I change tyres, something like a Furious Fred flys uphill compared to a bog standard knobbly.
Another thing is finding gains as the weather is changing, last night the terrain was blindingly fast and the hills only needed the outer it was so tarmac like, is this something the OP needs to be thinking about?

I wont bore you with all the details. Suffice to say that there are advantages and disadvantages to both.

That will do for me.

Thanks.

for Graham and everyone else a sort of scientific comparison story

I find it hard to believe that its true. Because if it were really this simple surely know one would be at the Olympics or World Cups on a 26er. They seem to suggest a 29 er hard tail is over a minute a lap faster on a 15 minute lap

http://velonews.competitor.com/2011/02/mtb/face-it-the-26-inch-hardtail-is-dead_251842Ok

PS not very hard to find it was on the first page of this google search

“26 vs 29 mtb measurement power”

Oh brilliant another study with the opposite result

http://autobus.cyclingnews.com/mtb.php?id=news/2006/mar06/mar03mtbnews

Tyres are obviously important, but I don’t think they explain the difference in this case My Trance has Nobby Nic Evo Pacestar run tubeless and the Gyro had pretty cheap OEM Mountain King tyres with tubes, but was still faster.

Since the thread has (inevitably) drifted into the usual 29er debate, can I just make a couple of points clear.

First, I’m not saying that the 29er was only better on the fire road climbs, that’s just the difference that I found hardest to explain so wanted to explore some more.

Second I’m deliberately trying to avoid getting into a 29ers are better/worse debate as I consider it to be pointless. If you are going to talk about better or worse then you have to define the task. And it has to be a lot narrower than “riding trails”. FWIW I’m still uncertain about 29ers in general. I like Orange bikes. Lots of people don’t; I do; let’s not go there. I liked the Gyro as a bike, regardless of its wheels. But I’m still not sure whether to go for it over the classic Five.

Check out the December 2012 issue of MBUK. Endurance rider Matt Page does multiple laps around Cwm Rhaeadr MTB trail regulating power output with a heart rate monitor. This course is almost equally split between up and down hill. The tyres used were Hans Dampf.
The Felt hard tail 29er was quicker than the Felt hard tail 26er.The greatest gains where in the uphill section.

This result mirrors Schwalbe’s lab tests that show 29er tyres have greater rolling efficiency.

Endurance rider Matt Page does multiple laps around Cwm Rhaeadr MTB trail

This course is almost equally split between up and down hill.

😀

Is MBUK a peer-reviewed scientific journal these days? I remember when it did Christmas photo comic strips with gratuitous female nudity. We’re all going to hell in a (20in wheel) handcart.

I don’t think these questions will ever be answered! I also ride recumbents, and in those..er..circles these same debates have been raging for years. Recumbents typically have wheel sizes ranging from 16″ up to 29″, and people have run tests and argued about wheel sizes, rolling resistance, bearing and drive train friction, not to mention the big subject of aerodynamics. I’ve heard it said that smaller wheels are more aerodynamic, accelerate faster, climb better (due to reduced weight), but they slow down in comparison to a larger wheel when the road surface deteriorates. It might be easier to feel and measure the difference between extreme wheel sizes, but it’ll become harder when there’s not such a difference between them.

So cheezpleez who should be believe, some bloke on the internet or those who carry out tests ?
The 2 German MB magazines use rather more objective methods than those in the UK. For example all bike frames put are on a deflection test rig. All suspension charted from damping measurements. All tyres tested for rolling resistance etc. The results published in numerical form that can be cross referenced with magazine tests from past issues. Do that and add in the subjective rider feedback and it’s frigging obvious the differences between wheel sizes.

Weight alone would dictate that the 26er is faster.

HOwever other factors like wind, how you felt on each day, whether you pedal in squares or not also come into play.

This is assuming you times yourself and measured your average heart rate on each climb – please tell me you weren’t so unscientific that you omitted this?

Bigger wheeled bikes go faster on smooth surfaces. Hence why road bikes have 29 (700) wheels. Smaller wheels give greater manouverabilty hence why bmx bikes have 20 inch wheels.

So dependant on what terrain you wish to ride with your chosen mix of speed, control and fun, you choose a wheel size between a bmx and a road bike 🙂

I’m wondering if a 26″ bike owner will have an epiphany every time they swing a leg over a 29er. It’s like getting a new car with oodles of power(said like clarkson) but after a few weeks its just a car… The power does not thrill anymore as your perception has altered.

Will your body adjust to essentially higher gearing? If you only had a 29er would you end up going slower over time as your body adjusts? I think the answer may be yes.

But the marketeers don’t care, because according to my puzzle, you’ve bought the bike already….

As well as bikes I ride Mountain unicycles

Hi feisty 🙂

Now I’ve resurrected my geared roadie 29er I’m all set to test your theory with a 29er muni – shall see how it compares to my 26er. Do you run the same length cranks on all, as to start with I’ll just swap the cranks from my smaller wheel (apologies am drifting into a conversation of limited interest to most, but can’t be bothered taking it elsewhere)?

Bigger wheeled bikes go faster on smooth surfaces. Hence why road bikes have 29 (700) wheels.

I thought we’d done this bit, and the Moulton track bikes, already.
Or was that another thread ?

No figures, but it certainly feels easier to trundle my fatbike up long fire roads than to ride my 29er.

It’s got 26″ rims so that’s one camp happy, and the diameter is the same a 29er, so that’s the other.

On a more serious note, this may lend some credence to the flywheel theory.

I think it’s a combination of tire deformation (rolling resistance) and to a lesser degree flywheel effect. Also with full suspension the lower roll centre means that the suspension isn’t as effected by pedalling motion.

Well, I chipped in with a comment some time ago and since this thread is still hovering about I thought that I would chip in with another.

I have read the information on the think the “Christhetall” gave earlier. Now although this might be compelling evidence for some for me it has, like almost everything else I read related to this, no basis for discussion.

I am a technical and analytical type of person, I question things to understand them. What I notice is that people who write about bikes, generally have very little knowledge about any technical aspects related to them. Material, performance or otherwise and for me this is quite clear and automatically devalues an article when i see some “non-truths or evidence on poor understanding.

So my point is that, I have little faith on much of what is written in the cycle press. The above, article is another such article. It lists many reasons why one bike may be “better” than another, but its lacking one thing….. evidence! there is not a single number substantiating any of it.

If the results are so clear, why are there no numbers? as mentioned by someone previously, there are clear trade offs. Maybe there are some advantages, but there will also be some disadvantages. We never get anything for free. For instance, increasing wheel size may increase stability, but it will also impact maneuverability. You will have to choose which you prefer and what suits you.

Gyroscopic effect is something that’s also talked about. Surely this is now scraping the barrel? I read an article where the author proved that gyroscopic effect has almost no influence when a rider is on a bike.

lets see numbers.

And another thing…..

Many of you chaps are probably familiar with the story about the guy who joined an olive company. The olive company was not making money (or something like that)and the new guy came up with a simple idea to turn things around. He went in to his boss and said “why don’t we take one olive out of every jar” Bingo, the company saved made a load of extra money.

Now picture this. you work in a bike company. Things are rather slow, sales are plateauing. A brainstorming meeting is called for. “we need something new. Something that other don’t have, will give us the advantage of being first to market and so on” One bright spark pipes up and says “lets make bigger wheels” and then in come the marketing department to make the case. Pros have to ride them as they are sponsored and then people have to buy them.

The bigger wheels thing has turned the whole bike industry around. There are so many people who buy what is new, just because it is new. This single change has had huge influence. Frame manufacturers, tyre manufactures and frame manufactures are all cashing in.

So lots of people cashing in, and big advantages for the industry, but still we see few numbers which support the perceived advantages for the consumer.

Now maybe they exist (i’m happy if they do) But what I would like to see is a more intelligent consumer, who questions benefits and does not get sucked in by marketing crap. By this I am not suggesting that people who now buy bigger wheels have done, its a general comment.

Just to add another perspective/query/arguing point in to the mix, both my bikes are now 29ers. One race weight hard tail and a full sus that is 4lbs heavier. They share the same wheels, running gear, saddle and bar set up. All my Strava times show the full sus is quicker. Everywhere. Apart from being quite annoying as I seem to have spent a load of money on a slower bike, it’s also very confusing. Puts a spanner in the argument for weight being the cause.
It must be an efficiency thing. Even with its clown wheels running low tyre pressure, my hardtail doesn’t feel like it rolls over things as well (as it shouldn’t I guess).
Also both bikes are quicker than my previous 26in bikes (as verified by Strava…)
This is just personal findings, and riding the South Downs 95% of the time is probably ideal 29er territory, although we do have a good supply of twisty wooded singletrack. I think at least part of it comes down to terrain.
Doesn’t really explain why my full sus is quicker though…

Well that puts my small mystery into perspective 🙂 How can a 4lb heavier full suss bike be faster “everywhere” than the lighter hardtail?

Serious Q? 4lbs makes sod all difference to conservation of momentum compared to good suspension, I though that was the ’29 vs 26′ argument of the late 90s. If I wanted to go faster for a given effort along my local trails I’d be on 100mm FS and just adapt my riding a little to suit it.

But “everywhere” must include climbing and suspension can never be 100% efficient so surely the HT must win uphill unless the surface is rough enough for the extra traction from the full suss to outweigh the losses in the suspension.

I’ve tried both on most of my local climbs. Some are pretty smooth, some are pretty rutted and some are rooty and steep, so quite a mix. A mix of gradients too. The full sus is quicker. Normally at least the top three times I’ve ridden each climb.
Even been out on the hardtail in the last week to purposely try and beat my full sus times. Not been able to do it.
Bikewise, we are talking Carbonal (Chinese) hardtail at 21 lbs against a Camber at 25 lbs. Both 1 x 10.
I even prefer the ‘feel’ of the hardtail… Go figure.

Sus is never 100% efficient between muscles and the ground, but neither is a hardtail – different efficiency gains and losses tho. It’s usually less about traction and more about rolling efficiency. Every time you get bumped off the saddle slightly, or even feel the bump, the bike had to lift or push up against your body weight. That action has a reaction that is a loss of fwd momentum. Sus has the same same gain here as bigger diameter wheels or wider, lower pressure tyres, until weight or ergonomics get really out of hand. Even more so on the flat / DH so the averages goes in a susser’s favour, assuming it’s a good design.

Feeling fast and being fast aren’t always the same. Many roadies love twitchy fidgety handling bikes as they simply feel faster ) I expect over a short course and under a strong rider a hardtail is faster, less power loss for a very fit rider. But a lot of it must be mental too, it feels fast thf they go fast.

But “everywhere” must include climbing and suspension can never be 100% efficient so surely the HT must win uphill unless the surface is rough enough for the extra traction from the full suss to outweigh the losses in the suspension.

It’s surprising how little rough is needed for suspension to be an advantage. I’ve got handlebar lockout (front and rear), so it’s easy for me to try the experiment, and even just based on feel* it has to be very smooth for me to consider using the rear lockout.

My full sus is lighter than most people’s hardtails though!

*all the proper scientific tests I’ve seen suggest that based on feel all riders underestimate the advantage of suspension smoothing things out.

chief9000 – Member
…Now picture this. you work in a bike company. Things are rather slow, sales are plateauing. A brainstorming meeting is called for. “we need something new. Something that other don’t have, will give us the advantage of being first to market and so on” One bright spark pipes up and says “lets make bigger wheels” and then in come the marketing department to make the case. Pros have to ride them as they are sponsored and then people have to buy them.

That’s plausible, but doesn’t work for me.

The reason I went for 29er as soon as possible is because when I was young I used to ride the old British roadsters around on dirt tracks in the African bush. We all preferred the 28″ wheels to the 26″ wheels because they rolled better and were faster. Easy enough to test on a downhill rollout.

There was no marketing genius behind that. At that time the more modern bike was the 26″ so our choices were based on our perception of the performance, not influenced by the current fashion.