Originally Posted by Uberneot
I bought a bike computer for my Dahon Mariner D7 today and I don't have a tape measure. Does anyone know the circumference for the Kenda 20" x 1.5" tires it comes with? The instruction booklet only has the codes for 26" and 700cc tires. Thanks!
An approximation on diameter is to take the bead diameter + 2 times the tire width.
Multiplying the diameter times pi will give you circumference.
1.5" is about 38mm.
Not sure if that tire is a 406 or 451, but a majority of 20X 1.5 tires have an ISO 406mm bead diameter.
Diameter = 406mm + 2x38mm =484mm.
Circumference= 484mm* 3.14=1520mm