Wheel Size (700?)

brownetara

Hi, My bike has a wheel size of 700 but the trainer I have has two settings 26" and 28" - where does 700 fit in? Thanks,

Cee-Jay-Cee

26"

quozl

A 700C wheel is 29". So I doubt it's 26". That's for smaller mountain bike wheels.

I'd try the 28". In places like Germany they call 700C 28" (check out rose bike for example). As the 700C wheel is really 28" diameter and with the tyre it's a nominal 29".

So again, i'd be pretty sure it's 28" you want.

Wishbone Ash

quozl wrote: »

A 700C wheel is 29"...

Isn't a 700c wheel 622mm?

quozl

It is Wishbone Ash, my mistake. It is however also referred to as 29" (when on a MTB) or 28" when in Germany (and doubtlessly other parts of the continent).

I think the difference between when it's a 29 and when it's a 28 is an assumption of a fatter tyre on a mountain bike 29'er wheel. Or it may just be marketing knobbery, I'm not sure.

It's all ridiculous and confusing but the one thing it never is, is a 26"

[edit] As I'm sure I'm failing to clarify things, here's Sheldon Brown explaining everything - http://sheldonbrown.com/tire-sizing.html . The thing I remember is that 622=700c=28"(Continental)=29"(large MTB). Whereas 26" is smaller MTB wheels. [/edit]

Cee-Jay-Cee

I had the same issue when setting up my new elite TT so I measured the diameter of my 700c wheel and it's 26" so I fitted the resistance unit in the 26" location. The TT works perfect that way. I assumed 28" was for fatter MTB tyres which would give a bigger diameter.

622mm is 24" and refers to the rim diameter only. The tyre adds another 25mm x 2 (2") onto both sides which brings the overall diameter to 26".

To be honest the difference in the two locations on the TT is so small that I couldn't see it making any difference which location the resistance unit is fitted in. Mine is in the 26" location and that's where it's staying.

quozl

Some TT bikes use 650 C wheels, particularly I think on smaller TT bikes. Perhaps your TT bike doesn't have 700C road size wheels, Cee-Jay-Cee? Or maybe your trainer is adjustable enough that 26" will cover everything short of 700c with big mountain bike tyres.

The OP can just try both and see which fits, I'm just curious now

Cee-Jay-Cee

quozl wrote: »

Some TT bikes use 650 C wheels, particularly I think on smaller TT bikes. Perhaps your TT bike doesn't have 700C road size wheels, Cee-Jay-Cee? Or maybe your trainer is adjustable enough that 26" will cover everything short of 700c with big mountain bike tyres.

The OP can just try both and see which fits, I'm just curious now

Sorry for the confusion, TT in my post refers to Turbo Trainer. My wheels are standard 700c wheels with 23 tyres. Overall Diameter of wheel and tyre is 26".

Al Wright

It's a bit confusing but the attached link to CTC website may help to explain;

http://www.ctc.org.uk/cyclists-library/components/wheels-tyres/tyre-sizes

A 700C-- wheel/tyre has a rim diameter of 622mm (approx. 24 1/2 inch). With a C23 or C25 tyre fitted the diameter of combination is just over 26 inches, BUT, in many instances the tyres may referred to as 28 inch

Cee-Jay-Cee

Al Wright wrote: »

It's a bit confusing but the attached link to CTC website may help to explain;

http://www.ctc.org.uk/cyclists-library/components/wheels-tyres/tyre-sizes

A 700C-- wheel/tyre has a rim diameter of 622mm (approx. 24 1/2 inch). With a C23 or C25 tyre fitted the diameter of combination is just over 26 inches, BUT, in many instances the tyres may referred to as 28 inch

Hmmm....very confusing. Why would a tyre/wheel that is no where near 28" be referred to as a 28???

The turbo trainer locations are for 26 and 28 inch wheels yet are approximately 10mm apart and fitted on an angled plane which is on a spring so it's compleltly irrelevant which location the resistance unit is fitted to as the spring brings the unit into contact with the wheel/tyre regardless.

quozl

Like I tried really badly to explain. The actual size of the wheel seems to have nothing to do with what it's called.

That same 700c wheel is also 622 (ero), 28" and 29". That's what it's called in different countries or even just depending on if it's being put on mountain or a road bike.

That's why I'm saying it's the 28" one - that's a common name for 700c. Even though a 700c wheel is more like 24" actual diameter (don't have a calculator to work it out exactly!).

So given a choice between 26" and 28" for a 700c wheel, the manufacturer intends you to choose 28".

Yes it's really dumb and I totally believe you that either fits for you :-)

Read the link from Sheldon above for more info or chalk it up to human stupidity :-)