Slightly dull turbo trainer related question

Posted on Thu 26th, July 2012

• #1

jim1985

Hi all,

Am just setting up my turbo and I need to adjust the resistance unit for 29, 28, or 26 inch wheels (so that the roller bit is in proper contact with the tyre)..

I run standard 700x23 tyres, and thought that it would be 28 inches. I set it up like this and the tyre and roller seem to be in an appropriate level of contact.

However, I've had a look at something I've found on the CTC website (http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3802) and it seems to suggest my wheel is 26 inch. But when I convert 700mm to inches, it comes out at 27.56 inches, making me setting it up for 28 inch wheels correct.

Anyone know which one I should be using? Apologies that:

(1) this is a boring question;
(b) i'm probably being an idiot

Cheers!
• #2

eone

"700" wheels are not 700mm, they're 622mm.
• #3

benbrangwyn

The bible for this sizing mess is here: http://sheldonbrown.com/tire-sizing.html
• #4

BrickMan

I always love how 700c is known as 28" (or 29?), yet its actually 622mm, which is 8mm <OD than actual 27" rims which are 630mm.
Mentals! And its about to get worse, esp in the MTB world where there will soon be 3 or 4 common sizes appearing.

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