TR7 Brakes,upgrade

[Tom Maddock]

I have purchase a set of Rover SD1 calipers and discs etc NOS.

What discs do I need or can I modify the SD1 discs.

Going to one of the specialists is a dear option and doesn't fit with the way I work,they are only using standard discs not having something specialy made.I prefer to find out what they are using and source direct.

All help appreciated.

Tom

[Alec Pringle]

Hi Tom,

 

Which variety of SD1 calipers, 2 or 4-pot; and which discs, solid or vented ?

 

My only experience of SD1 fitments is utilising the SD1 hubs also and larger diameter wheels.

 

Bear in mind that the TR7 utilises a 4-stud 241mm diameter disc as opposed to the SD1 which is 5-stud 258mm. The standard TR7 disc is also thinner, I think only 10mm, whereas the SD1 discs are something like 15mm solid or 24mm vented, give or take a couple of mill. The TR8 disc is, I think, 3 or 4mm thicker than the 7 disc, and fractionally bigger diameter. Princess discs are I think 270mm/13mm, and would require larger diameter rims.

 

None of the various braking permutations that I have use standard discs, they're all modified in one respect or another, and/or with hub adaptors.

 

Cheers,

 

Alec

Edited January 9, 2009 by Alec Pringle

[Alec Pringle]

Hi Tom,

 

afterthought, just checked the Capri discs - solids are 248mm/13mm (3 litre), and vented 245mm/20mm (2.8 litre).

These do fit into 13" rims with the appropriate hub adaptors.

 

Cheers,

 

Alec

[Guest Wayne S]

When you come to fit the SD1 calipers to your TR7 strut, you will need to leave out the spacer washer to get the clearnces right, or at very least put a thinner one in. Rimmers do sell SD1 vented discs modified to fit the TR7 hub with the SD1 calipers. Part No. RB71117A. The cost of buying them is cheap when it compares to the time spent re-drilling other discs and the potential for making a mistake.

[Alec Pringle]

Hi Wayne,

 

you're probably right on the cost angle - 'setting up time' to machine a small production batch of discs is one thing, for an odd pair it can get pretty costly. At least some of the various conversion kits I've seen over the years have actually used 'blank' discs with the hubs then machined to suit the TR application . . . as opposed to drilling extra holes in a disc already finished for its original application. I've never been convinced of the merits of surplus holes in a disc, common logic suggests it's a means of unnecessarily weakening the installation - perhaps not so important in a road car of modest performance, but relevant to competition useage.

 

As for the rest of the hydraulics, the greater volume of piston fluid may well require a larger master cylinder . . . which may in turn require a matching servo.

 

Cheers,

 

Alec