Converting an old steel frame to run disc brakes

[ishaw]

Re: Re:

Aren't they aluminium?

Mine is 100% steel for sure. I think they came in both flavours.

 

[ishaw]

Re: Re:

I'm planning on doing my Sunn over the winter. Make my own tabs, braze 'em on with an additional strut between seatstay and chainstay.

Tab placing is down to the IS documentation, a bit tricksy to find but once you have it the actual placement is easy; make up a triangular template, fit it, work out how your tabs need to look, put them in place (by bolting them to the template), braze.

Check a disk will run in your frame before starting, obviously. It would be a bugger to grind off your brake bosses, braze on tabs, and then find you can't actually run a disk...

Good thinking. I'm not planning to do this myself as I don't have the welding kit and haven't welded anything for over 20 years. Hoping to find someone on here or a reputable place to do it.

 

[tufty]

Make sure your dropouts are straight before giving it to anyone, the IS disk mount is aligned to the inner face of the dropout.

I'm gonna have to make up an alignment jig, I'l be more than happy to lend / put it into circulation it when I'm done.