British-Cars.org

Welcome to the DMR Site for British Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - RV8 discs with princess calipers?

I was wondering if anyone could help me out here.

I have a pair of princess calipers with a spacer kit kit ready to fit to my GT. I was going to go down the usual route of fitting Pug 505 Turbo discs, which would need re-drilling to suit the MGB hubs.

However, would a pair of RV8 discs bolt straight or does the RV8 have a different hub pattern? I know its four stud but not sure if the PCD is different to that of the B. The RV8 calipers certainly look almost identical to the Princess units.

Cheers, Paul

Paul Grundy

I have also been looking at a similar mod and have been trying to find information about using the RV8
discs on MGB hubs and utilizing either 2 or 4 pot SD1 calipers. They are much more readily available than Princess calipers.
Best of luck Paul
Brian
b bourne

If I remember correctly the vented peuguot discs are the same diameter as standard mgb discs (about 273mm), but the rv8 discs are the same size as SD1 discs which is about 264mm; therefore you get a greater swept area on the peuguots. I have fitted pug discs to my GT; it was a simple job for the local machinist to redrill the disc mounting holes to suit the back of the hub. He also put a thin brass spacer around the hub to take up the gap on the inner bore of the disc where it slips over the back of the hub. It isn't strictly necessary but it means all the leverage on the disc isn't being handled by the mounting bolts alone.
I used spacer tubes from the V8 Conversion Co over the caliper mounting bolts to enable rover vitesse sd1 4pot calipers to bolt straight on with no other machining. I have dispensed with the brake backplates as mine were rusty anyway. I have converted the twin feeds on the caliper to single feed by routing a solid brake pipe back out of one of the inlet holes to the nipple hole on the top of the caliper. One of the forum members kindly sent me a photo of how they had modified their caliper... I can email a copy of the pic if needed.
My only concern is that the vented 4 pot caliper is a wide beast, and the caliper side interferes with the back face of the MGB wheel. On my V8 wheels a 15mm spacer would be needed; apparantley a 13mm spacer is needed on LE wheels. I don't want to use spacers on my car. After fitting a decent set of brakes I intend to use the car for track days and fast road work, so I don't want the worry of what effect spacers are having on my steering geometry.
KN Minator in a 15" size fit over this brake combination without interference, although I don't know precisely what offset. Having said that, the offset should not matter for caliper clearance (obviously it does for suspension/bodywork clearance though.) It is more a factor of the actual shape of the back of the wheel spokes as to if there is enough caliper clearance. Maybe some other forum members could help with naming suitable wheels that would fit without spacers?
Nick Bentley

If it helps, I have a drawing I can email you of the Peugeot disks, with all dimensions. If you can find someone with an RV8 (maybe on the RV8 board) you could compare.
Pete Green

This thread was discussed between 23/01/2006 and 03/02/2006

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join this live forum now