Show me your roller cams, U brakes

[Owwwwk]

Haha. No problem. Thanks for helping. Now the search can start for a nice rollerbrake that also does brake well.

 

[classen]

Cunninghams and some Steve Potts have a larger diameter stud.

 

[Swede]

Cunninghams and some Steve Potts have a larger diameter stud.

Would that explain this?

The arm with the larger ID comes with a sleeve/insert but I couldn't explain why.

 

[classen]

I'm betting there were some other early U-brake mountain bikes (mid 80s?) other than Cunningham and Potts that also had this larger diameter stud. Suntour licensed the rollercam design from Charlie Cunningham, and I'm guessing that some of there earlier models had the Cunningham specified post diameter before they established the u-brake/rollercam "standard" stud as we now know it with the 8.9mm stud.

Do you know were the larger diameter one came from?

 

[Swede]

They're NOS, so haven't been fitted to anything. Both arms are marked "CG" which according to Velobase is 1987 (C) and July (G). Not sure why Suntour would offer both as the larger ID version could be used on all variants of stud (at that time), but the more I dig into this the more descrepancies I find.

 

[halaburt]

The larger one (10.89mm on your calipers) is about the size of the early/original studs (which was 3/8"). It's possible those were supplied by Suntour with a stainless steel cap that slides over the stud before mounting... as that's what all the later WTB RC's had as well so they would work on either size stud.

 

[24pouces]

I had the same problem with my BOI Fat Chance fork with Roller-cam studs. Impossible to fit all my U brakes on them.
After looking for information, it was for WTB rollercam. But they are so rare…

The solution I have found is to drill up my U-brake with a 9,5mm and all is OK now.

On other hand, a friend got some problems with his 1988 cannondale SM600 with the studs threaded out (and not inner or female as usual)
And He doesn't find any U brake to fit on them. Perahps some Dia-Compe.
But on the 'dale, you could replace the studs…

 

[danson67]

After looking for information, it was for WTB rollercam. But they are so rare…

It might be worth contacting Dave Garoutte at DKG Engineering.
He did most of the machining for WTB/Cunningham/Potts parts.

All the best,

 

[Swede]

I had the same problem with my BOI Fat Chance fork with Roller-cam studs. Impossible to fit all my U brakes on them.
After looking for information, it was for WTB rollercam. But they are so rare…

The solution I have found is to drill up my U-brake with a 9,5mm and all is OK now.

On other hand, a friend got some problems with his 1988 cannondale SM600 with the studs threaded out (and not inner or female as usual)
And He doesn't find any U brake to fit on them. Perahps some Dia-Compe.
But on the 'dale, you could replace the studs…

My 'dale came with no studs and I've used these.

http://www.shop.brake-stuff.de/en/edelstahl/166-canti-studs-brake-bosses-for-u-brakes-in-size-m10.html

 

[euphras_1]

...
On other hand, a friend got some problems with his 1988 cannondale SM600 with the studs threaded out (and not inner or female as usual)
And He doesn't find any U brake to fit on them. Perahps some Dia-Compe.

You/he have/has to look for the original XC Roller Cams. They came with "male" studs, but these are hard to find, much harder than the later XC Sport, XC Sport 7000, XCD 6000 and so on. A pic from a 1984 catalogue: