Wheel size

[Jimod]

How do you measure a wheel on a bike? My grandson's wheel measures 20" on a tape but the tyre on it says 24" x 2"

 

[jerrysimon]

Although the rim diameter may measure 20" diameter edge to edge don't forget you have to add the width of the tire * two. So in your case a 20" wide rim with 2" * 2 width tires would be 24"

How to measure your bicycle wheels

or

http://www.wikihow.com/Measure-a-Bicycle-Wheel


There is more complication when selecting tire sizes though as described in detail by the late great Sheldon Brown

Regards

Jerry

 

[Jimod]

Many thanks.