Got a technical headache here.

What is the biggest tyre I can use on a 21X2.15 front rim? Can I use a 120? I'm sure I can use a 90 though.

21X3 and 21X3.5 should not have issues with the 120 size tyre but what if I use a 90 on that rim?

The main issue is.. I have a 120 size 21" tyre. What should the ideal rim size be? Or does it even matter? I'm guessing the tyre would balloon sideway more on a smaller 21X2.15 rim and it would be taller on the bigger 21X3.5 rim. Is my guess correct?

Thanks.

 

No one with any clue on this?

 

120 smallest is 3.00

90 you can stretch onto a 3.00 (ran my WW's this way for 20k 2 sets of tires)

on a 120 i would use a 3.5 since it sits in the middle of recommend for most 120/21 tires.

 

Clue: Nix the 2.15 idea

 

ya, skinner front = all over the place on grooved roads/bridges lol....