Fatter tyres are faster and 29er tyres roll faster according to this study.

As i have read often on this forum; “pulls up chair” 😮

may roll faster, but doesn’t deal with the fact everything being equal the 29er will weigh more than a 26er, and the 29er will be harder to turn, which may or may not be a problem depending on the trail you are riding.

real world, you buy a bike, you ride it, does it really matter?

Harder to turn? says who really…magazines?, folk say this but it is bull,

Seems fair enough in my experience – nothing surprising there. Doesn’t mention tubes vs tubeless. I’d always been convinced that, though heavier, the deformation between the tyre and tube cost energy?

The importance of tread pattern is no surprise to the off-road world

ah so they read the forum then

coastkid, a 29″ weighs more it is will be harder to turn, basic physics, now to my next point, in the real world who cares.

one of key phrases from quick read thro` is limit of human detection of rolling resistance difference is 5%; so basically may not be able to notice any of the differences they found in highly specific lab tests.
I always believed that rolling resistance was, generally within sensible limits, of low importance in teh energy output required to ride a bike. Topically trying to ride into the current gale force winds would IMHO be far more of a noticeable effect than a change in tyre type 🙂

a 29″ weighs more it is will be harder to turn

Harder to accelerate or decelerate, you mean.

AND harder to turn poppa due to the greater gyroscopic force of the mass being further from the hub

…the 29er will be harder to turn…

In the same way that a box of 29 matches is harder to pick up than a box of 26 matches.

AND harder to turn poppa due to the greater gyroscopic force of the mass being further from the hub

although in the real world, with all the other stuff going on, you don’t notice it, IME

In the same way that a box of 29 matches is harder to pick up than a box of 26 matches.

massive misunderstanding of basic physics three MTG.

I’ve never ridden a 29er hungry monkey, so can’t comment on experience. It is interesting that no DHers ride 29ers, even though they roll faster….

You pays your money and you makes your choice…..

I had a quick blast on one and it didn’t feel as responsive, so I wouldn’t buy one, because it doesn’t suit the things I like doing on my bike.

If the equation holds – 29er faster than a 26er, the logical conclusion is right here!

http://mtobikes.com/black-sheep-bikes-zamer-36er-mountain-bike-review/

Massive misunderstanding of irony there, leggyblonde. 😛

I turn the ‘bars on my 29er, it goes round the corner.
There is no “harder” about it.

My point is that if you are moving at a constant rate on flat ground, the mass of the wheel will make no difference whatsoever as to how easy it is to turn. F=ma.

There must be a cut off where the more stop start the ride the more energy you waste on a 29 er acclerating the wheels.

My hunch is that the fastest is very finely balanced and will be very specific to a particular route

Are 29″ not impossible to manual/drop? I had thought the rear centre distance would make the nose hard to lift.

There is no need to manual a 29er.
Faced with such overwhelming awesomeness, obstacles simply move out of the way.

Yes, absolutely. However we don’t ride at constant velocity, therefore in accelerating and braking the larger and heavier the wheel the less efficient it is, and the same is true for changes of direction. Horses for courses.

Poppa. mrmo means harder to steer turn not rotate turn. THe gyroscopic effects will be larger on a larger wheel when you turn the handle bars.
Whether this is noticeable or not is another matter…
Interesting about the 5% difference required to be perceptable. If you’re racing that’s a big difference. Even allowing for air resistance being the bigger factor that would lose you a lot of time in a race. Hmmmmmmm

You can manual and drop 29ers, but it is harder. They(well mine) is faster, even on singletrack, it turns well and accelerates ok too!

i did a wheelie on my 29er last week,i couldn’t do them on my 26″ bikes

What’s every ones opinion on doing down hill drop offs [26 V 29]?

I am lucky enough to have 3 bikes, Trek EX8, Ragley mmmBop play bike and a Scandal 29er, the 29 er is by the lightest of the three, to say that a 29er is always heavier Is rubbish, you can get away with lighter wheels and tyres due to their size.

I truly believe it is horses for courses, if it comes to long days on the bike on not to technical terrain, than the 29er eveytime, its quicker, lighter and once up to speed flatters a not to fit guy like me.

If it gets steep, very rocky or includes drops and jumps, then 26er everytime

29er is always heavier Is rubbish, you can get away with lighter wheels and tyres due to their size.

Please explain how a bigger wheel is lighter? and i mean like for like. I don’t think anyone is saying 29ers can’t be lighter, but if you set out to build a ightweight bike a 26er will eventually turn out to be lighter than a 29er because the forks can be shorter the wheels and tyres lighter.

Please explain how a bigger wheel is lighter? and i mean like for like

More air between the spokes – sort of like a Wispa vs a Yorkie.

built like for like, a 29er is bound to be heavier than a 26er, its common sense.
however, as it has a larger diameter it wont have to be accelerated to the same speed (in rpm) as a 26er would, thats probably they dont feel worse.
however, a 26er is also bound to be more efficient over bumpy terrain, due to the fact that a larger diameter wheel wont ‘drop’ into small holes as much as a 26er would, thats why they ‘roll’ better.
(to understand the last part, think about a skateboard wheel hitting a tiny stone, which may punt you off into the bushes, then a bicycle wheel hitting the same tiny stone.)
RE: turning, a 29er may be slightly heavier, but for a given speed it will be rotating slower so the gyroscopic effect will be slightly less.
so, basic physics suggests that although the 29er may weigh more static, this weight is not so noticable when moving.
however, none of this matters for me, im a short arse.

sorry, meant 29er would be more efficient over bumpy terrain ^^^^ typo.

What I meant was that you would tend to use a larger rim and a larger width tyre to get the same grip, I tend to ride with 2.3 or 2.4 width tyres on 26″ bike, but 2.2 or thereabouts on 29er. The extra contact patch with the ground and the way a 29 er wheel rolls over the ground compensates I feel for using a lighter build wheel or tyre.

Riding hard tail 29er feels like riding 100-120mm full sus 26 bike in comfort stakes, but is horses for courses, some places one excels and visa versa.

Ask me to do fifty miles over the south downs tomorrow I’d pick the 29er everytime, rocky alpine descent with quick switchbacks, then the 26er

29er wheels are weaker though. For the same rim depth they have longer spokes and deflect laterally more than a 26″ and they deform over a larger area at the rim during compressive loading decreasing spoke tension in more of the spokes at the MOI. Combined with lateral forces, they are more likely to buckle in off road use than a 26″ wheel in the exact same situation.
If you look at road race wheels compared to track wheels, the forces are different and so is the wheel construction. Shorter spokes and deep section composite rims are used in track and Timetrial wheels to control the lateral stress applied during sprinting to make the wheel more efficient for the task.

I’ve also heard the argument that 29er frames have lower COG as you can place the BB below the wheel axles. I’ve never seen any more than 2″ below the axles, and this is basically where a 26″ wheeled bike’s BB would be.

The steering issue is not valid as the head angle on 29er bikes is steeper to compensate for the gyroscopic effect of the larger wheel.

So they may be better for taller riders, but overall it depends on the riding style and intended use.

problem is that research like this is useful but very contextual, for example

the key to reducing rolling resistance is minimising the energy lost to casing deformation

so therefore get those tyres right up to 8bar !! oh, er….

the 29er argument will never be solved by scientific fact because there are too many human and extraneous factors, so the argument will never be concluded, it will just roll and roll

… the head angle on 29er bikes is steeper to compensate for the gyroscopic effect of the larger wheel

You’re making this up now, aren’t you ?

I getcha, sorry.

That’s a point I considered when the tyre size was mentioned. Lower vloume tyres run higher presssures so the contact point is decreased by comparison.
So the bigger wheel has the same contact patch but is deflected more easily due to the higher tyre pressure.(if run with a lower volume tyre obviously)
Couple this with shorter or zero suspension, and you’ve got a wheel that loses contact with the ground more often.

So the millions spent in suspension R&D hasn’t been wasted after all.

Nope. A 26″ wheel bike with 100mm travel generally has a head angle of 70degrees or less and most are about 69 these days. Most 29ers with 80mm travel are 71 degrees with more offset in the fork crown.

the head angle on 29ers is usually steeper to compensate for the radius of the bigger wheel.

bigger wheel = more ‘trail’ (google)

steeper head angle = less trail

bigger wheel + steeper head angle = about the same ‘trail’ as a 26er with a slacker head angle.

which is fine, but it does alter the weight distribution (more weight over the front wheel).

you might like this, or not.

[More energy is expended in arguing the merits of 29er vs 26er than is gained or lost in actually riding them 🙂

Thatvis a fact!

UK knows it Drofluf. 😉

If you look at road race wheels compared to track wheels, the forces are different and so is the wheel construction. Shorter spokes and deep section composite rims are used in track and Timetrial wheels to control the lateral stress applied during sprinting to make the wheel more efficient for the task.

Huh? That’s for aerodynamics, because air resistance is a far far bigger factor the wheel deflection! People ride double disc wheels on the track, but not on the road because they’re too much of a handful! Deep section rims have only become popular since the weight limit was introduced, so they could do more interesting things and keep the weight the same. Cipollini and sprinters of his era didn’t use deeps.

How much difference does this actually make then. They say the old Spesh tyres are 25% slower. as they’re clearly not saying that by changing tyres your bike would roll at 25mph not 20. What proportion of overall drag is rolling resistance. I suspect pretty tiny compared to air resistance.