Brake Caliper Clearance

[Aragorn]

Does anyone happen to have a modular rim laying around that they could stick a tape measure across? I'm trying to work out how much radial clearance i have for the disk/brake caliper on a modular compared with landrovers offerings.

The stock landrover steels appear to provide around 390mm, however they quickly taper down to a much smaller diameter. A set of disco alloys i have have around 385mm but that doesnt really taper away. The dimensions and perhaps a photo of the inside of a modular would be excellent!

Cheers

Kev

[zoltan]

I'll take a couple of pics for you and post them up later, I'll also run a ruler over the mount face. I'm just off out to tackle the crank speed trigger wheel and sensor bracket on my 110

[Steve Hiatt]

I've had similar issues with my racer which is very tight on clearance. Different modulars have different clearances, I've had two lots from Paddocks that looked identical, but one rubs and the other doesn't. One was Chinese, the other Taiwan, from memory.

Disco steels will give you the most room, at least that's what I've found.

[Aragorn]

Steve: what size disks are you running on your racer?

I recon the limit is somewhere around 340mm. I've found a couple suitable disks that will enable me to retain the original caliper, one 330mm and one 345mm. 345 would be nice, but i think i'll be struggling to get it in.

[zoltan]

I laid a rule across to give you scale, the steel rule is laying on the hub face so you can gauge a diameter from the ruler

The tape measure gives you diameter at the tyre bead

[Aragorn]

Cheers Zoltan.

Seems what steve is saying is spot on, yours measure 385mm ish whereas someone else has quoted me 390mm. My Disco alloys also measure 385mm, so i suspect i'd be wise to work to that as a "maximum" width, which drops me back to a maximum of a 340mm disk.

I guess i could look at getting the 345mm disk machined down by 5mm seen as i'm going to need the centre modified anyway, or alternatively, i could look at using a slimmer caliper of something else, but they tend to be things like Porsche Cayennes, and while a tasty set of Porsche-Brembo 6Pots would look awesome, i'm not sure its sensible to stretch to that kinda expense!

[zoltan]

The one piece Brembo calipers are wide: designed around 32 and 34mm wide discs. Whilst you get your diameter the 'spoke' clearance is always an issue

[Aragorn]

Thats not so much an issue on the landrover, as the calipers/disks sit really far back due to them bolting onto the rear of the hub. Modern cars tend to have the disk sitting over the front of the hub, and as a result the caliper sits much closer to the spokes.

A 30mm disk would be nice too

[Steve Hiatt]

My front discs are 315mm, which just leaves room for a HiSpec caliper. The caliper is close to the spokes which reduces the clearance, as you have identified. I recall when looking at calipers that Porsche Boxster ones weren't outragous, but I did get the price from a mate who worked at a dealership.

[Aragorn]

It was the Porsche Cayenne / Audi Q7 / VW Touareg calipers i was looking at.

They're only about £200 each new, which for an alloy 6 piston brembo is quite impressive.

Boxster and 911 ones dont have the piston area to match the defender calipers, so you end up actually losing braking torque. The Cayenne ones also dont have the same area, but they're bigger than the 911/Boxster ones and the rest is offset by the larger disk.

Not really sure what i'm going to do now.

I;m thinking it might be more sensible to simply build it up now using standard parts, then altering it later once the truck is actually built and on the road, instead of spending £600+ on brakes when the engine and box still isnt attached together.

[zoltan]

Change your master cylinder bore and restore line pressure that way? It does mean you'll need to attend to the rears as well unless you strike lucky and find a stepped bore m/c