Laying out a bolt circle?

Jul 05, 2005 45 Replies

Well, they don't do any work at road speeds ( rmember virtually all our cars are frontwheel drive with load proportioning valves to limit rear brakeline pressure, so I don't see the need. Also the handbrake mechanisms are a real pain. Every rear caliper I had to change on the VW worked perfectly as a hydraulic device.... except that the mechanical handbrake mechanism would fail, therefore a certain fail on the UK annual roadworthiness test (MOT test). That was a Girling design that is used on LOTs of European cars. The separate mini drum for the hanbrake used by Porsche is OK, but if you are as mean as me, that makes disc replacement horrendously expensive!

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Ah, not if you put those on the front where they do the most good.

Ah that sounds like the older Saab arrangement. Little shoes on the inside of the "hat" of the normal disk, yes?

Right, but when the disks are good for 80,000 miles+, it's not that big of a burdon for me.

I don't like drums either, but they are usually lighter than the equivalent disc setup. Improved Touring racers in SCCA often stay with drums on the rear of stock-based cars for this reason, and they work fine. Fronts do almost all the work anyway

I think Chevrolet had to recall a bunch of pickups when they first came standard with rear disks a couple years ago. The calipers were sticking from lack of use.

Hm, didn't know they were lighter. Maybe that varies. But yeah, calipers are simpler anyway, at least if they're done right. Less fiddly bits and flying springs to deal with, and let's not even get into the self-adjusters.

There was a famous story back in the late 70's of the Saab test driver taking the managing director out for a demo of the "works" Saab 99 rally car. Suitably impressed, the MD asked for a go, & during his effort, he tried a handbrake turn at a steep downhill hairpin... When they recovered the pair of them from the stream several hundred feet down the valley, it became apparent that the MD didn't know the handbrake now braked the front wheels ----------------------------------------------------------- snipped-for-privacy@boltblue.com

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