Assuming the same size gearing is it easier (ie less effort) to ride a bike with 29” wheels than the same bike with 27.5” wheels, and to take it to the extreme 16” wheels.
As an example, if I rode the same course at say 200 watts on 29” wheels would I be quicker than the same course at the same power on 27.5” wheels assuming all else is equal?
Cheers,
Ben
..... for I have become the Jedi of flippers
" an extravagance is anything you buy that is of no earthly use to your wife "
no clear answer as you need to nail down the specifics, small wheels spin up easier and are more areo, arnimal with their small wheels were banned from tt/velodrome cycling competition, then there is rolling resistance, size of contact patch and the surface you are riding on.
you are talking in mtb size so i would imagine the 29’er will be quicker over normal xc rolling terrain.
best way to find out is to try it.
A bike with smaller wheels is effectively geared lower, everything else being the same.
If smaller wheels made you faster, then all the pros would ride with smaller wheels.
Pete
Not what you ask but …..Larger wheels (29er)will roll over / plough through rougher terrain faster than a smaller wheel regardless of gearing , the “thing” now is to go mullet …….. 29 front 27.5 rear .
I would say 29’rs are faster on the road AND easier to pedal. I ride with a lad he is fairly unfit. Im riding 26” he 29” both mtb. Off road we are similar. Once we get on stony tracks or tarmac he leaves me behind.
Thanks for the replies.
Just as I thought rely but not having enough technical knowledge about the specifics.
Not really a mountain bike specific question (I don’t ride mountain bikes) but am considering a gravel bike, nothing serious just canal,paths and light off road really. I know most frames allows for wider tyres if you 650b but to be honest I can’t see a benefit for myself going down this route.
Cheers,
Ben
..... for I have become the Jedi of flippers
" an extravagance is anything you buy that is of no earthly use to your wife "
Ben I run a gravel bike. It came with 35 mm Clement Explor tyres. They are like a file tread they were fine on gravel tracks / canal paths, but as soon as the going got muddy they slip N slide.Originally Posted by ben4watches
I ended up using my gravel bike as a winter (Oct to April) bike and put Continental 4 seasons on and dropping to 28mm. Again its fine on fire roads, quicker than the 35’s but no contest in the mud.
Steve
“Gear inches” is a good way to look at bike gearing, ie how far the bike moves forwards with one revolution of the pedals.
It depends in the surface, and to some extent tyre pressures. A Brompton (16” wheels) on tarmac is off out of the trap incredibly quickly. As for other surfaces I’d say your more dependent on tyres, mechanical soundness and particularly tyre pressures than size when you are up to 27.5/29 sort of size.
This.
ALL other things being equal a larger wheeled bike will be higher geared than the smaller wheeled one - just visualise a penny farthing, bigger wheel = bigger gear = harder to pedal.
However, all other things are rarely equal, and the example above of the 29er being faster - I bet there are a lot of differences between the two bikes, not least the 29er likely to be more modern, and the larger wheels being better on rough terrain, etc..
So 29ers were introduced in the MTB world to roll over rough terrain that 26” struggled with. This allowed the suspension travel to be reduced from 180,160 to 140cm eg less bob , but more importantly lower cost. Then they realised a 29er front and back was a “ big tall” bike. So work commenced on Mullet bikes 29 front 27.5 rears to allow a bit more rearward movement with the 29 front.
As an aside there were 27.5 front and back. So have a look and decide for yourself. Me Im sticking with 26” f/r old schoool on my MTB.
BTW this has nothing to do with the OP who wants a gravel bike so that will be 700c or 650b if he goes fattie.
Last edited by higham5; 31st October 2021 at 20:56.
@higham5
are 700c and 650b different from 29” and 27.5”? I thought they were the same just referred to differently
Cheers,
Ben
..... for I have become the Jedi of flippers
" an extravagance is anything you buy that is of no earthly use to your wife "
You can easily do your own calculations with the Sheldon Brown gear calculator.
F.T.F.A.
A 650b wheel and a 27.5" wheel will have the same Bead Seat Diameter (584mm). From a marketing perspective, the 27.5 is more likely to be an MTB rim and will probably be wider rather than a 650b which will be a road rim (the b indicates it's a medium road width - although to be honest I've never seen a 650 a, c, d or e so I'm guessing that element is just a hangover from the past).
Same for 700c and 29". MTBs adopted the '29er' tag years ago even though it'll have the same BSD as a 700c rim. Guess they didn't want to be mistaken for roadies?
So in answer to your question, pretty much yes.
Please don't get me started on 27" wheels which, with a BSD of 630mm are actually bigger than both 27.5/650b and 29/700c. I had a client's bike in the other day and it took a little while for me to notice the difference! There was an attempt a while back to standardise the whole wheel diameter question but I think it just ended up with one more measurement than no-one really used.
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