20" wheel BMX canti stud locations

[crumpton]

Any you guys have data on canti stud location for 20" wheel BMX rears? Height off shortest point of the drop and ctr to ctr width would be interesting.

Thanks!

[Rosko]

Any you guys have data on canti stud location for 20" wheel BMX rears? Height off shortest point of the drop and ctr to ctr width would be interesting.

Thanks!

Nick, The variation in rim width, depth and tire size varies so much with 20" bikes that any standards you do find tend to be off. If you can get your hands on the part, the frame and double check.

[crumpton]

you telling me there is no standard axle to post ctr for 20" bmx?

[sam]

linear pull on seatstays, or ubrake on chainstays?

[steve garro]

The lowest my chart goes is 227-232 for a 24" cantilever.
Under the CS U-brake is the way to go to avoid heel clip, or calf clip........
Or a rear 140mm disc
This may be a case of "Ask Sheldon Brown"

- Garro.

[crumpton]

canti/V on seatstays. but i will just head over to local BMX shop with some measuring devices, pad and pen.

[crumpton]

The lowest my chart goes is 227-232 for a 24" cantilever.
Under the CS U-brake is the way to go to avoid heel clip, or calf clip........
- Garro.

steve, its a special project bike where they have spec'd a V brake on the seatstay. all to show off a bunch of uber BMX parts from germany.

[steve garro]

steve, its a special project bike where they have spec'd a V brake on the seatstay. all to show off a bunch of uber BMX parts from germany.

Then I would want them in hand - Paul Cantis hit different then Shimanos, (you know this)
I would bet this bike will be bad-ass!
- Garro.

[Rosko]

you telling me there is no standard axle to post ctr for 20" bmx?

Well if you follow the accepted axle-stud spacing for the other wheels sizes and scale down canti-V location would be 1/2 ISO bead seat Diameter minus 26-28mm which may work as a starting point. As I was getting at earlier, in BMX the listed standards are often so outdated they are far off the numbers that actually work. It's been my experience with 20" frames that one should always check twice. Just a suggestion.

[jon_norstog]

It's true. There are two rim sizes, the standard 20 (406 ISO) and the mini (451). If you use the Pauls you can just barely set them up so you can run either size wheel. That's an advantage on a kid bike. Your best bet is to get your components in hand and build the bike from there. For instance a lot of BMX hubs deviate from the 110 width standard, enough to cause problems when trying to stuff the wheel into a stiff BMX rear triangle.

Good luck!

jn

"Thursday"

[Brian Smith]

One way in which a lot of BMX v-brakes differ from their MTB counterparts is an extended brake pad slot, facilitating easier fitment despite axle position changes after gear swaps. Most of these slot extensions are in the direction traveling away from the hub axle. This means that if you had designed the frame stud locations for the axle to be near the middle of the dropout slot, and then your gear change made the axle position slide forward toward the BB, you could still get the brake pads to hit the rim.
If one of the uncommon components being chosen for this bike are brakes, and if the manufacturer isn't providing this feature in the brake, then you may have the chance to identify this need to that manufacturer. Even the dropout slot angle to seatstay angle influences the ability of everything to work together. I'd suggest you measure thrice, design flexibly, or get customer approval...

[crumpton]

Thanks for the education guys. I'll wait till I have the brakes and wheel in hand.

[Freddy Salgado]

Look forward to FNL pics!