tyre sizes

jackfeeder Posts: 269
edited April 2010 in Road beginners
a mate of mine is looking to get back to cycling.
He has an older bike which has 27*1 1/4 inch wheels.
The tyres he has on at the moment are 20 - 622 (700*20c).
Is he able to fit 23 -622 tyres to those wheels or does he need to check the rim size/width?
All my life I've wanted to be someone; I guess I should have been more specific.


  • John.T
    John.T Posts: 3,698
    They can not be 27*1 1/4 wheels if he has got 20-622 tyres on them. 27" wheels are xx-630.
    622 is the rim size where the tyre bead sits so any 622 (700c) tyre will fit on a 622 rim. Rim width will affect how widw a tyre can be used safely. Most road (race) bikes are now sold with rims suitable for 700c-23 tyres but will take from 20 to 25 with no trouble, 28 at a push.
    See Sheldon Brown for info on tyre sizes.