Front Brake Upgrade 278mm Discs - Ford Callipers
Discussion
Lewis's Friend said:
I'm using EBC discs from an st150, so that's a 278mm diameter. I believe the height is 48mm, but would have to check that....
If the Mintex equivilent is MDC1807 then that disc in the WIKI, listed at 45mm thick. So plus your 14mm spacer gives 59mm. Which is similar to the set-up using the Cossie 283mm disc at 55mm high plus a 3mm washer.Lewis's Friend said:
.. I have the drawing at home that I can post if it would be helpful, with the specific dimensions I used?
Feel free to add a line to the WIKI once you have everything sorted out but let me know if you need any help with that. The easy way to do it is to copy and paste the last line and then change the information as necessary.I'll be fitting one of my 887/888 carriers tomorrow to work out what disc height I need.
Top Gear TVR said:
14mm spacer...... Gulp, that's a lot more leverage than intended....
You're right, it is quite a bit. I designed the spacer to have the biggest possible contact between hub and caliper. It appears to be fine but we'll see how it goes after an extended test period. If it becomes a problem, I'll just buy some of the taller discs and have the spacers milled down to suit.
This is the 260mm disc I have fitted currently....
and this is the same disc with the 887/888 carrier...
So this implies that there is sufficient clearance for a disc with a maximum diameter of ...
260mm + (2 x 12mm) = 284mm less the "standard" clearance of (3.28mm x 2, say 7mm) = 277mm
and the ideal height is 59mm.
All of which confirms what TGTVR has done by turning down the Cossie 283mm disc to 278mm and shimming out by 3mm.
There is another factor to consider, and that is the thickness of the plate with the wheel stud holes. A disc from manufacturer A with a plate slightly thinner than another from manufacturer , will sit nearer the center of the car then the thicker one. Negligible I know, but there never the less.
I have a pair of 283mm Cossie discs on order so we'll see how the theory compares with practice.
and this is the same disc with the 887/888 carrier...
So this implies that there is sufficient clearance for a disc with a maximum diameter of ...
260mm + (2 x 12mm) = 284mm less the "standard" clearance of (3.28mm x 2, say 7mm) = 277mm
and the ideal height is 59mm.
All of which confirms what TGTVR has done by turning down the Cossie 283mm disc to 278mm and shimming out by 3mm.
There is another factor to consider, and that is the thickness of the plate with the wheel stud holes. A disc from manufacturer A with a plate slightly thinner than another from manufacturer , will sit nearer the center of the car then the thicker one. Negligible I know, but there never the less.
I have a pair of 283mm Cossie discs on order so we'll see how the theory compares with practice.
Edited by v8s4me on Sunday 24th January 23:24
Top Gear TVR said:
14mm spacer...... Gulp, that's a lot more leverage than intended....
I can't see how the thickness of the spacer can compromise the brake upgrade at all? Imagining the forces involved and the disc effectively trying to rotate the caliper with it I can't see how the spacer will be subject to much force at all, let alone 'leverage'. Plus a 14mm thick block of solid stainless is hardly fragile 
As long as the bolts are the correct grade I am sure it'll be fine
The 283mm discs arrived today and a trial fit shows that they will need to be turned down to 278mm. It's sooo close though. They clear the carriers, just, but catch the caliper when everything is clamped up. 278mm will leave the edge of the disc 3mm above the top edge of the pad.
There's no probelm with clearance inside the Estorils...
I meant to get an 8-spoke out to check that, but forgot.
And the "spacer" needed is a thin (1.36mm) washer, so the original length caliper bolts will do fine.
This is so nearly an "out-of-the box" upgrade.
There's no probelm with clearance inside the Estorils...
I meant to get an 8-spoke out to check that, but forgot.
And the "spacer" needed is a thin (1.36mm) washer, so the original length caliper bolts will do fine.
This is so nearly an "out-of-the box" upgrade.
Edited by v8s4me on Wednesday 27th January 22:51
v8s4me said:
Here is a photo of the 887/888 calipers inside the 8-Spokes....
Even allowing for the weights there is enough clearance - just.
I have 278's on mine Joe and they were just kissing the weights. Not an issue (for long) but when I got the blue rinses put on the fitter placed the weights on the inside edge.Even allowing for the weights there is enough clearance - just.
Where did you get your 283's from and what were the vehicle details you used. Callipers look good.
I probably could have done the maths 25 years ago but alas now I can no longer remember and can't be bothered with a Google search type response. It's brakes so I'm on high caution: The way I think is how would I feel we multiplied the spacer length by say 10 and got 140mm. Would I expect a bolt of the original diameter to cope under heavy / emergency braking. Nope it would worry me lots.
By that logic: standard is two mating faces and no length of bolt to stretch or deform when under strain. At 140mm it might be likely to fail. At 14 it would be worse than no spacer. On TGTVR I went with a standard 'thick' washer of approx 1.6/2mm. A negligible difference I thought. New correct bolts with loctite stuff on them.
I'm sure a design guy could do this more justice ?!?!?
As long as the bolts are the correct grade I am sure it'll be fine
By that logic: standard is two mating faces and no length of bolt to stretch or deform when under strain. At 140mm it might be likely to fail. At 14 it would be worse than no spacer. On TGTVR I went with a standard 'thick' washer of approx 1.6/2mm. A negligible difference I thought. New correct bolts with loctite stuff on them.
I'm sure a design guy could do this more justice ?!?!?
AceOfHearts said:
Top Gear TVR said:
14mm spacer...... Gulp, that's a lot more leverage than intended....
I can't see how the thickness of the spacer can compromise the brake upgrade at all? Imagining the forces involved and the disc effectively trying to rotate the caliper with it I can't see how the spacer will be subject to much force at all, let alone 'leverage'. Plus a 14mm thick block of solid stainless is hardly fragile As long as the bolts are the correct grade I am sure it'll be fine
The Horse said:
Where would I find the wiki with all the info on this Fiesta ST upgrade ?
It's with some other useful Wiki's at the top of the S series ForumThe Horse said:
And how easy is it to get the 283mm discs "turned down" to 278mm ?
You need to find yourself a friendly little engineering/machine shop that'll do them (it's a simple job in machining terms) for a bit of cash 
Just to add to this old thread... If you are going to use 557/558 calipers from the ford fiesta ST150. The calipers get swopped over.
IE. On the Tvr S the 558 goes on the passenger/nearside, the 557 goes on the drivers/offside (UK car).
This is because on the Ford fiesta, the calipers are mounted in front of the wheel, but on the S, the caliper mounts behind the wheel.
It matters, if/when you need to buy just one caliper later on....
TerryB.
IE. On the Tvr S the 558 goes on the passenger/nearside, the 557 goes on the drivers/offside (UK car).
This is because on the Ford fiesta, the calipers are mounted in front of the wheel, but on the S, the caliper mounts behind the wheel.
It matters, if/when you need to buy just one caliper later on....
TerryB.
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