Split discs

DaveEFI · Post by **DaveEFI** » Tue Apr 20, 2010 8:22 am

I'm intending doing a rear disc conversion to my SD1, and the usual way involves fitting modified discs from another model, and mods to the rear hub too to take them.
I've obtained some aluminium bells which fit straight on and use AP flat discs - but these cost a fortune. Any sources of a cheaper alternative? It's only for normal road use.

CastleMGBV8 · Post by **CastleMGBV8** » Tue Apr 20, 2010 9:43 am

Dave,

Check out the equivalent disc from Brembo. you might be surprised at the price through a Motor factor.

I had new Brembo front discs fitted to my Rover Sterling coupe and they were very inexpensive.

Kevin.

ian.stewart · Post by **ian.stewart** » Tue Apr 20, 2010 10:18 am

Rear Brakes, Probably more cost effective to use some other source of disc, BMW?? or similar and elongate the stud holes to get the discs to fit, well worth a trip up your friendly breakers with a vernier in hand to see whats near

kiwicar · Post by **kiwicar** » Tue Apr 20, 2010 11:36 am

Try later Jag discs for the XJ and XK that go over the wheel studs, not the older type that mount on the back of the hub carrier, I am pretty sure SD1 and jag use the same stud PCD so no re drilling.
Mike

chodjinn · Post by **chodjinn** » Tue Apr 20, 2010 12:18 pm

Sierra cosworth calipers and Mercedes solid discs, bolts straight on as far as I remember, that's what I'm running on my MGB. Cheap and effective, and perfect for track and road use. cheers

DaveEFI · Post by **DaveEFI** » Tue Apr 20, 2010 1:11 pm

chodjinn wrote:Sierra cosworth calipers and Mercedes solid discs, bolts straight on as far as I remember, that's what I'm running on my MGB. Cheap and effective, and perfect for track and road use. cheers

It's Sierra Cosworth callipers (vented discs) I've got and intending using.

However, the (more) common conversion uses Rover 800 callipers and discs.

The 800 discs need the centre machined to fit the spigot - and the half-shaft flange machined to clear the inside of the disc 'bell'. And I'd rather not have to get machining done unless there's no option, so a bolt on solution is what I'd really like.

I've obtained a pair of custom made ally bells for a racing SD1 that simply bolt on where the drum went. To these are bolted AP plain - i.e. flat - discs which are available in a variety of diameters and thickness. So no machining. And the ability to return the car to standard more easily if needed.

Of course it would be great to find some production car discs that fitted without modification - but I've a feeling others have tried and failed.

Other thing is I want to keep the standard 15" Vitesse wheels.

I've only got very basic workshop facilities which don't include a lathe - no room for one. And any time I try and get such things done round here it costs a fortune.

ian.stewart · Post by **ian.stewart** » Tue Apr 20, 2010 4:15 pm

I can probably machine the discs for you if you get stuck

SuperV8 · Post by **SuperV8** » Wed Apr 21, 2010 4:02 pm

Have a look at Wilwood. Rally Design sells them I think.

They do rotors for ally bells, maybe lucky and find they use the same PCD.

Tom.

topcatcustom · Post by **topcatcustom** » Wed Apr 21, 2010 6:19 pm

Did Olly not say that some Mercedes discs bolt straight on and work with your Sierra callipers??

harvey · Post by **harvey** » Wed Apr 21, 2010 6:52 pm

kiwicar wrote:I am pretty sure SD1 and jag use the same stud PCD so no re drilling.
Mike

They're not the same. Jag are the same PCD as Chevy IIRC, but not Rover.

stevieturbo · Post by **stevieturbo** » Wed Apr 21, 2010 8:43 pm

Just make your own then. Its easy, especially if you have access to a lathe.

2 piece disc setups come in a multitide of sizes, no of bolts, and bolt PCD's.

So just because you have bells, doesnt mean that anyone else is going to make discs to fit your particular bells.

Wilwood stuff is generally cheap, and they sell universal bells that require machined, and their discs are generally quite cheap.

Although it would be a lot easier and cheaper just to buy a solid disc from a car and use that instead. A little bit of measuring and research will find something.

It doesnt need to get complicated.

DaveEFI · Post by **DaveEFI** » Thu Apr 22, 2010 9:58 am

topcatproduction wrote:Did Olly not say that some Mercedes discs bolt straight on and work with your Sierra callipers??

Well, he refers to an MGB. As far as I know it has a different axle from the SD1. And the callipers I have are for vented discs - although that's not essential if you can use solid ones. I say that because the callipers for vented front discs on the SD1 and different from those for solid ones - they have a spacer between the two halves.

But obviously I'd love to find production car ones which bolt straight on.

If there are ones, the actual model they are for would be a great help.

SuperV8 · Post by **SuperV8** » Thu Apr 22, 2010 11:34 am

Am I right in thinking the PCD is 5x127?

What are the critical fitment dimensions you need for the rear disc?

Spigot dia? (location hole dia)
Total height of disc?
OD?
Max Thickness?

Let me know and i'll have a look through my databases.

Tom.

DaveEFI · Post by **DaveEFI** » Thu Apr 22, 2010 12:45 pm

SuperV8 wrote:Am I right in thinking the PCD is 5x127?

What are the critical fitment dimensions you need for the rear disc?

Spigot dia? (location hole dia)
Total height of disc?
OD?
Max Thickness?

Let me know and i'll have a look through my databases.

Tom.

I'll need to measure things later, but:-

It needs to be an exact fit on the spigot on the rear hub, as well as fitting the studs.

The inside of the 'bell' has to clear the hub assembly.

Thickness suitable for use with Sierra Cosworth rear callipers, preferably ventilated.

Diameter and swept area same as above - provided it will fit a 15" wheel.

The only detailed instructions on fitting rear discs to an SD1 I could find used Rover 800 parts - and this involved removing the drive shafts to machine the flange, and also machining the discs. I'd rather find an easier way.

stevieturbo · Post by **stevieturbo** » Thu Apr 22, 2010 5:31 pm

DaveEFI wrote:
SuperV8 wrote:Am I right in thinking the PCD is 5x127?

What are the critical fitment dimensions you need for the rear disc?

Spigot dia? (location hole dia)
Total height of disc?
OD?
Max Thickness?

Let me know and i'll have a look through my databases.

Tom.
I'll need to measure things later, but:-

It needs to be an exact fit on the spigot on the rear hub, as well as fitting the studs.

The inside of the 'bell' has to clear the hub assembly.

Thickness suitable for use with Sierra Cosworth rear callipers, preferably ventilated.

Diameter and swept area same as above - provided it will fit a 15" wheel.

The only detailed instructions on fitting rear discs to an SD1 I could find used Rover 800 parts - and this involved removing the drive shafts to machine the flange, and also machining the discs. I'd rather find an easier way.

You need to use discs to suit your calipers. You cant just decide solid...but preferably vented. SO what calipers and carriers are you using ?

And as said, it will be easy to make your own from Wilwood's universal stuff.

Just choose the right bell blank

http://www.rallydesign.co.uk/advanced_s ... ll&x=0&y=0

then get it machined to suit...and buy a disc that will bolt on

http://www.rallydesign.co.uk/advanced_s ... or&x=0&y=0

Under a 15" wheel you might be able to squeeze 300mm, but it will be damn tight.

Circa 280mm would be a sensible maximum.