I didn't see this talked about in the archives.
What are the 24" bmx frames really designed for.. 507mm or 520mm rims?? Is it too close to matter? I'm building a junior up for my oldest and want to know if one size is preferable to the other before I order my rims and spokes. I'm not sure if he will race it or not so its not a big deal if the tires are the fatter 1.75 or skinnier 1 1/8". Or even 1" or 1.5 or 1 3/8 will work.
I see there are higher grade tires available in the 520mm size than the more common ISO 507mm wheels. I'm thinking I may go with the 507's anyway and just run the cheng shin comp III 1.75 tires though.
As far as brakes go, the 13mm difference means 6.5mm more reach is needed for 507mm. Which I don't think is any problem for most brakes.
For the 20's I know the jump from the 20x1.5 ISO 406mm rims up to the 20x1 1/8 ISO 451mm rims is big enough that it causes problems with brake reach..
Anybody have any advice?