wheel size

[stephenjubb]

imagine a ride performed twice over 10 miles, once on 20 inch wheels, the other on 700cc wheels, with everything identical except the wheel size would it be substantially quicker on the 700cc wheels?

I ask because I am on a bike with 20 inch wheels and think if I got a bigger bike with bigger wheels for the same physical effort would I get to my destination over 10 miles much quicker?

If so this would mean instead of doing 50 miles on tour on 20 inch wheel for the same effort I may get 60 miles in the same amount of time per day?

 

[jimboalee]

Nope.

No difference, as Dr Moulton proved.

The reason why 20" wheels are a disadvantage is potholes feel worse, hence the full sus on the Moulton.

Behold a thing of beauty.

 

[BentMikey]

Nope. No difference, as Dr Moulton proved.

Unfortunately this is not quite true. The real situation is fairly complex, involving a trade-off between more aerodynamic drag and lower rolling resistance for the larger wheels. I'd suggest the difference is probably not big enough to matter very much.

 

[fossyant]

Usually down to tyres and weight of equipment and the 'body' sat on top of it.....

 

[HF2300]

Wouldn't it also be the case that if everything was otherwise identical i.e. including geartrain the different wheel size would change the overall gearing?

In other words, the relevant question isn't 'everything identical' but 'same rider, same circumstances, different bikes designed for the same job'?

 

[Origamist]

Scroll to the bottom to find a table listing the advantages and disadvantages of small wheels.

http://www.users.globalnet.co.uk/~hadland/page15.html

Velocio (aka Paul de Vivie):

"That universal agreement has fixed on 70 centimetres as the proper size for wheels does not in any way prove that this diameter is best; it simply proves that cyclists follow each other like sheep.... Make no mistake, uniformity is leading us directly towards boredom and towards routine, whilst diversity, even though it distracts us, holds our attention, our interest and the spirit of enquiry always on the watch. To change is not always to perfect, and I know that better than any others newly come to cyclo-technology. But to stand still, to sink into a rut, that is the worst of things for industries and for men."

 

[jimboalee]

I like my 'small wheel'.

Behold a thing of beauty.

 

[Twenty Inch]

Wouldn't it also be the case that if everything was otherwise identical i.e. including geartrain the different wheel size would change the overall gearing?

In other words, the relevant question isn't 'everything identical' but 'same rider, same circumstances, different bikes designed for the same job'?

Gearing makes a difference. If the same gearing is used on both bikes, ceteris paribus, the 20 inch wheel will travel less far per revolution so take more revolutions for a given distance.

This is why my Dahon folder has a chain cog the size of a dinner plate.

 

[BentMikey]

The point is of course all else being the same, apart from wheel size difference...

 

[Landslide]

"That universal agreement has fixed on 70 centimetres as the proper size for wheels does not in any way prove that this diameter is best; it simply proves that cyclists follow each other like sheep.... Make no mistake, uniformity is leading us directly towards boredom and towards routine, whilst diversity, even though it distracts us, holds our attention, our interest and the spirit of enquiry always on the watch. To change is not always to perfect, and I know that better than any others newly come to cyclo-technology. But to stand still, to sink into a rut, that is the worst of things for industries and for men."

It does make it a lot easier to find replacement tyres though!

 

[HF2300]

The point is of course all else being the same, apart from wheel size difference...

Exactly so.