Just built a 29'er. Will I ever ride on 26" wheels again?

[wookiee]

Re: Re:

My opinion...
Its not all about the physics, sometimes its more about the organic mass driving the machine!
Doug

I'm not questioning peoples observations that bigger wheel bikes ride better for them, just that the difference may not be solely the a product of the wheel size.

Also small variations in geometry can make have large effects on handling, which makes comparison of even similar bikes difficult.

For accurate comparison you would need to have bikes that were effectively identical apart from being scaled up. In this case all that would change is the relationship of the rider with the bike smaller/larger bike and the tyres with the ground.

I have a 1988 Highpath that though designed for 650b wheels, due to having 2" of mud clearance and 100mm wide BB shell will also fit 29er wheels. I guess that swapping wheels around on that would make for an interesting comparison as the only things that would change would be the steering geometry and BB height.

I recently set up a 26" wheel bike to mimic the geometry of my 29er. It had modern kit XT double drivetrain, clutch mech etc and a decentish wheelset some modern 2009 rockshox reba sl forks etc. But it just didn't feel as good as the 29er...It was basically a scaled down version of my 29er...

 

[GrahamJohnWallace]

Re: Re:

I recently set up a 26" wheel bike to mimic the geometry of my 29er. It had modern kit XT double drivetrain, clutch mech etc and a decentish wheelset some modern 2009 rockshox reba sl forks etc. But it just didn't feel as good as the 29er...It was basically a scaled down version of my 29er...

Either the 26" bike would be too small for you or the "29er" too large. Though apart from that you they should be comparable.

Sometimes the differences between bikes can be subtle, I have two almost geometrically identical bikes, but one consistently out climbs the other. I can't work out the reason and can only think that it may be to do with either the handle bar height, or that the forks on the better climbing bike are heavier.

Surely, some manufacturer must make 26" and 29" bikes where the only differences are the wheel axle height and that the steering geometry has been recalculated to get the same characteristics from for the larger wheel?

 

[PurpleFrog]

Re: Re:

I have a 1988 Highpath that though designed for 650b wheels, due to having 2" of mud clearance and 100mm wide BB shell will also fit 29er wheels. I guess that swapping wheels around on that would make for an interesting comparison as the only things that would change would be the steering geometry and BB height.

The problem you are up against here is that bicycle physics is seriously complicated, especially the physics of stability and steering. You can't evaluate bikes using numbers unless you understand the relevant physics, and even experiments can be tricky without and adequate theoretical model. One of the factors that drove Fisher towards 29ers was that the BB - and hence c-o-g - could fall relative to the axles. Which makes doing comparisons on the same frame pointless, because the frame isn't using one wheel size or another correctly.

As for opinions from riders: yes, there's a lot of room for placebo effect, misinterpretation, etc, confounding factors, etc.

 

[NeilM]

Re:

The implication that all people who buy or build a 29'er are idiots buying into a combination of placebo and marketing hype is both wrong and insulting, and frankly, if you have not ridden 20 to 30 miles on a 29'er, then you are not in a position to make valid comment on what any one of us has experienced.

As for cost, I have spent a faction of the cost of my Cats Wiskas or DOGS BOLX on building my 29'er.

Go and ride an xc race like Mountain Mayhem and take note of all the guys who are consistently fast, most, if not all of them are riding 29'ers.

 

[Mike Muz]

Re:

For me, all the time I have the technical ability and fitness to do so, I will ride my 26ers more. However, as I get older and lose both, I may well find the 29er gets more use. If in the unlikely event that I want to race, I will still ride a 26er. Im old enough to know I'm not going to win a race any more, so it doesn't matter to me if I come 30th or 70th. It's just fun for me at the end of the day.
Isn't that what all bikes are for?
Obviously, if I want to go somewhere fast I'll take the road bike. Hmmmm. Isn't that 29" too? :facepalm:

Mike

 

[PurpleFrog]

Re: Re:

The implication that all people who buy or build a 29'er are idiots buying into a combination of placebo and marketing hype is both wrong and insulting

People believe stupider things for much longer all the time, so "It's insulting" shouldn't really affect the argument - hifi forums are full of idiots convinced that $2000 amps that sound the same as $100 in blind tests are worth paying for, not to mention "power conditioners" and magic cables that fly in the face of physics. In cycling, St Keith Bontrager himself said that if test riders report bike A as bing faster than B, then things were probably the other way around. And a few years ago roadies were going insane over ceramic bearings that could have no measurable impact on performance, and even today many believe that reducing wheel weight will have impossible benefits.

But, for what it's worth, I believe that 29ers do handle differently to 26s - in a way that often makes them faster and easier to ride offroad. I suspect the real differences are that a 29er tyre of the same diameter as a 26 has 25% greater volume (??? guess it depends on tyre design - it might reasonably be only 5%, depending), that the bikes have longer chainstays, and that BB drop is significantly greater. Angle of attack due to increased wheel size makes intuitive sense and fits the riders' impression of the bikes... but when you look at the actual change in angle, it's too small.

 

[The History Man]

And larger contact area? I run 30psi in the 29er and have to be much higher for 26. This would improve 'feel' also. Never have been one for fashion. My builds are testament to that. I agree with Neil that to dismiss the views of those who have actually ridden the bikes back to back is at best disingenuous and at worst ignorant.

They do feel different. The physics is of little no consequence. They just do.

 

[GrahamJohnWallace]

Re: Re:

The implication that all people who buy or build a 29'er are idiots buying into a combination of placebo and marketing hype is both wrong and insulting, and frankly, if you have not ridden 20 to 30 miles on a 29'er, then you are not in a position to make valid comment on what any one of us has experienced.

I must also be insulting myself though as I currently have two 29ers, three 650b and three 26" bikes in my garage.

I agree with Neil that to dismiss the views of those who have actually ridden the bikes back to back is at best disingenuous and at worst ignorant.

Does this refer to me?

My average ride would be 20-30 miles with a big day ride of about 50/60 miles. Of course there are advantages of one wheel size over another but in my experience these are not anything like as large as those reported by some others.

The reasons commonly sited as for why bigger wheels "roll better" can be measured and quantified. And the gains are nowhere as large as you would expect from the hype. So either the claims for 29ers are being exaggerated, and we are being conned, or more likely the sensation of "rolling better" is real but the cause is being overlooked.

Go and ride an xc race like Mountain Mayhem and take note of all the guys who are consistently fast, most, if not all of them are riding 29'ers.

Does this transfer over to the top level of the sport?
Are 29er bikes dominating the race results?

 

[PurpleFrog]

Re: Re:

The reasons commonly sited as for why bigger wheels "roll better" can be measured and quantified. And the gains are nowhere as large as you would expect from the hype. So either the claims for 29ers are being exaggerated, and we are being conned, or more likely the sensation of "rolling better" is real but the cause is being overlooked.

My very strong belief is that "overlooked" is correct (possibly with a little exaggeration too.)

And that arguments based on "You have to believe exactly what I say or you are dissing me!" really have no place anywhere.

 

[The History Man]

You can chose to disbelieve without being rude about the views and experiences of numerous others. It is this kind of ignorance I suggest GJW overcomes. Or is he the only one in step? Whatever the reason, our experiences being dismissed in such a condescending manner is the issue.