Sunday, August 17, 2008

Lightweight brakes

Don't come any lighter than these!
Well having a measure, the rally design bells are too big, they are 7" bolting centres for the disc, so the bell needs to be almost 8" in diameter.

To use this setup I'd need to make my own bells on a 5.5" disc bolt pattern...cause the rally design ones are 7" and larger discs really...Also cause of the 14" wheels I cannot have a bell with a larger O/D than 6.5", the minimum safe material size is 6.44".

6.5" also cause 7" will push the caliper out more or foul it. This forces me into the 5.5" pattern discs.

These come in 260mm and 266.7mm.

Some messing the cardboard discs and sized caliper printout tells me I need the 266.7mm. Cause the 260mm will leave the caliper too close the outer edge of the bell, or need a chamfer. With 266.7 there is no great clearance issue.

The stock offset on the disc is 1/2", so the bell is quite simple, it would be a piece of 1/2" thick alloy, sized on the o/d to 6.5". The centre will need a 66mm hole to slip over the hub. It will need 4 holes for the disc to hub bolts, and 6x M8 size holes with a recess for a socket cap bolt on a 5.5" pattern. It will need a flange on the back to locate the disc, for concentric reasons.

I can hopefully poach a set of caliper brackets, as if the offset is setup right, I can pack the radial mount calipers out from the disc to cover the difference from the 247mm discs in kit the brackets were intended for, as now using a 266mm disc...So a 9mm pack on some well made washers. Or I can just make my own brackets from some alloy bar.

Not sure if its worth the effort, just messing about seeing whats do-able.

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