Is there such thing as canti to u brake adapters?

Woz · Mar 9, 2023

It's basically a different frame altogether or frame modification.

My first MTB had a U-brake on the chain stays - very powerful, bosses had to re-welded twice. Brake booster worked good with them.

..... can't actually recall any bike with a U-brake for a front brake.

Mod-Master · Mar 9, 2023

Woz said:
It's basically a different frame altogether or frame modification.

My first MTB had a U-brake on the chain stays - very powerful, bosses had to re-welded twice. Brake booster worked good with them.

..... can't actually recall any bike with a U-brake for a front brake.

Some sort of Saracen had double u brake

dbwheels · Mar 10, 2023

Mod-Master said:
As I’ve learnt that u brakes wont fit on canti bosses, I’ll see if the Rb hive mind can shed some light on this. I’ve researched and found nothing on people putting u brakes on canti bosses. Is there such thing as an adapter? As @FluffyChicken said u brake bosses are in and up a bit.

Would you have to remove the bosses and machine an adapter to fit? Would you have to reweld the whole thing?

Would appreciate any info cheers

About a brazillion years ago I wanted to do the same thing in reverse. Get the U brake off the back of my Cannondale in favour of cantis.
I think I drew up a sort of conversion plate

but never got around to making it. I'll dig around and see if I still have the mastercam drawing. You would need to start with a canti mount that has removable pivots, though.

Edit:
In the meantime I found these locating dimensions;

1. For Cantilever bosses-

"26" (559) 255 mm from the axle to boss and width 75-85 mm for canti-bosses."

Here
https://www.mtbr.com/threads/looking-for-source-to-fork-brake-mount-specs.490337/
2. For Roller cam/Ubrake bosses-

"The mounting bosses for the XC brake are to be brazed onto the front fork at a distance of 310mm above the center of the front dropouts (when using a 26x1.75 rim) The mounting bosses for the seatstays should be brazed onto the stays at a distance of 312.5 to 314mm from the center of the rear dropouts. The distance between the bosses on the stays or the fork blades is to be between 84 and 94mm. The ideal is 88 to 90mm"

Here
https://www.mtbr.com/threads/roller-cam-brake-help.481955/

dbwheels · Mar 10, 2023

Now I remember why I didn't do it.
Look at the attached drawing. Remember that I wanted to go from U Brake to canti...it would have meant that the canti bosses hung out in the wind, unsupported; too much resonance and chatter.
If you are going from canti to Ubrake, it might work if you could add a 3rd attachment point on the brake bridge (if there is one). Make the plate out of 1/4" alloy. Could work, I guess.

FluffyChicken · Mar 10, 2023

Odyssey U4 Booster plate.
Have a look at them (proper Alu one, not the fancy Ti one).

I have a feeling these can be used for a conversion but don't quote me on it.
Maybe something Mavic too?