Aston Martin rear Brembos

[turboboy]

I have a pair of spanking new rear calipers from a aston v8 vantage, appearance wise and fitment they are the same as the Leon Cupra r but piston wise they are different.

The pistons measure in at 26mm.

My question is are these any good to use as front calipers on my Leon Cupra?

I'm aware there is a calculation to compare the braking force they will give and then I can compare to my 54mm single piston calipers. Does anyone know how to work this out? How will these compare to my standard calipers? Are they going to be worse the same or slightly better?

Any help would be great

 

[JamesL]

I don't know the formula, sorry... But where did you get them from?! They would look awesome!

 

[turboboy]

As I said in my first post mate they look exactly the same as LCR calipers same size,mounting and everything just they say Aston Martin on them and the pistons are different sizes (smaller unfortunately).

 

[vroomtshh]

They'd be useless. Rear brakes aren't designed to offer the same sort of braking pressure as fronts.

 

[turboboy]

They'd be useless. Rear brakes aren't designed to offer the same sort of braking pressure as fronts.

They may be useless but not for the reason you have stated. They may be useless due to piston size not because they are rear brakes.Piston size is the only difference and people fit 996 rears as fronts because the piston size is adequate

 

[turboboy]

I should of stated in my first post I'm talking about brembo 4pot calipers. The Aston uses 4pots on the rear.

 

[Slimy]

You could just work out the braking force based on the surface area of the pistons. With the 54mm piston having a surface area of 170mm, and the 26mm pistons having a surface area of 81mm each, it's a drop of about 4%.

 

[turboboy]

just the type of answer i was looking for thanks..

seems people struggle when a question comes up that doesn't relate to "what dump valve do i need" or "what air filter shall i buy"threads.

slimy,do you know if you can fit bigger pistons and smaller seals?

 

[Slimy]

Very unlikely, you're talking fractions of a millimetre (and probably less) between the piston and the caliper.

However, my maths might be out, I've just noticed the Aston calipers you mentioned are FOUR pot? So it's four lots of 81mm not two like I worked out. My bad.

Watch the master cylinder though, it may not be able to cope.

 

[ben450]

Sling them on ebay mate and make some money from them and then get some new brakes to suit

 

[turboboy]

thats what will happen if they arnt powerful enough (if thats the correct term) but i would rather some facts and figures and data that i can see rather than just an opinion because we can't work it out..

someone must know how to work it out..

 

[ben450]

thats what will happen if they arnt powerful enough (if thats the correct term) but i would rather some facts and figures and data that i can see rather than just an opinion because we can't work it out..

someone must know how to work it out..

Someone must know out of my league though. Have you tried ringing someone like Hi Spec and asking them?

 

[vroomtshh]

They may be useless but not for the reason you have stated. They may be useless due to piston size not because they are rear brakes.Piston size is the only difference and people fit 996 rears as fronts because the piston size is adequate

Why ask if you think you know the answer?

Ever driven a car with 996 rears on the front? I have, and they're bloody dangerous. The rear calipers provide nowhere near the force that's required for fronts.

 

[cupra.al]

i cant see them being a problem especially as them brakes are designed to brake the wheels that drive the v8 vantage as the v8 is rwd.
the standard mk4 cupra calipers only had small pistoned 4 pot calipers and they stopped the car awesomely,ive heard many say they are as good as the tt 312mm brakes
so the the aston martin brakes cannot be worse than the standard leon front 280mm discs especially as the discs are 330mm there probably better than 312mm brakes as they are 18mm smaller.

 

[turboboy]

Why ask if you think you know the answer?

Ever driven a car with 996 rears on the front? I have, and they're bloody dangerous. The rear calipers provide nowhere near the force that's required for fronts.

I don't know the answer but I was expecting the worst..i would except they were no use for the fronts but wanted to go on the maths of it not you coming on and saying there rear brakes,there no good. No I haven't driven a car that's got 996 calipers but there are more than one reason why the brakes on the car you drove weren't up to standard. I've heard good things about 996 brake and yes I've heard bad but is the bad due to crap discs pads,badly bled brakes.

Like I've said I wanted the Maths of it so I could compare x to y and we could see the outcome,I'm aware that just because there 4pots doesn't mean they are an upgrade.

Doesn't look like I'm going to find the answer here though seems everyone is too used to giving advice on air filters, dv,and diagnosing coil pack faults that have been covered time and time again and then some more. This thread would be seven pages long by now if it was one on them threads.

 

[vroomtshh]

The maths of it doesn;t work how you think it does though, so comparing piston sizes is the same as comparing apples to oranges.

Having a 50% bigger piston area won't give you 50% more braking. And having two pistons with the same area, doesn;t mean they provide the same braking effort.

I could probably go find out some proper clamping force figures for the calipers for you, but why would I, when you keep moaning that all people know about is Dvs and coil pack faults

 

[vroomtshh]

I stand corrected

Your standard Leon Caliper with 54mm piston will provide 3847lbs of clamping force (approx)

The Aston V8 calipers will provide 3423lbs of clamping force (approx).

So they maybe won;t be that bad. 996 rears are still a disaster though

Formula in case you need it

556 (psi) x px3.14xr2 x 2 (single pot)
556 (psi) x px3.14xr2 x 4 x 2 (4 pot)

p = 0.98
3.14 = pi (I can't find a pi symbol lol)
r2 is obv radius squared

Obviously theres a lot more to brake effort than just the clamping force of the calipers.
But I assume you'll be using bigger discs, better pads and fluid anyway, so all in, you'll probably see a slight improvement.

If you want to tell me your current pads, and new pads, size of old and new discs, and distance from the centre of the discs to the centre of the calipers, I could probably give you a better idea how they'll compare.


Personally, I'd stick them on ebay and buy a GT junior kit.

 

[Muttley]

The only thing that would worry me about using rear calipers on the front is the handbrake mechanism. What kind of handbrake mech is fitted to the Aston Martin rear calipers, and can it safely be left disconnected?

You'd probably have remember to use a windback tool when changing the front pads as well.

 

[vroomtshh]

The only thing that would worry me about using rear calipers on the front is the handbrake mechanism. What kind of handbrake mech is fitted to the Aston Martin rear calipers, and can it safely be left disconnected?

You'd probably have remember to use a windback tool when changing the front pads as well.

Handbrake is a completely seperate mechanism. And you don;t use a wind back tool on 4 pot calipers

 

[turboboy]

I stand corrected

Your standard Leon Caliper with 54mm piston will provide 3847lbs of clamping force (approx)

The Aston V8 calipers will provide 3423lbs of clamping force (approx).

So they maybe won;t be that bad. 996 rears are still a disaster though

Formula in case you need it

556 (psi) x px3.14xr2 x 2 (single pot)
556 (psi) x px3.14xr2 x 4 x 2 (4 pot)

p = 0.98
3.14 = pi (I can't find a pi symbol lol)
r2 is obv radius squared

Obviously theres a lot more to brake effort than just the clamping force of the calipers.
But I assume you'll be using bigger discs, better pads and fluid anyway, so all in, you'll probably see a slight improvement.
If you want to tell me your current pads, and new pads, size of old and new discs, and distance from the centre of the discs to the centre of the calipers, I could probably give you a better idea how they'll compare.


Personally, I'd stick them on ebay and buy a GT junior kit.

much more the type of answer i was looking for and thanks for taking the time to work it all out...

this is also useful in the future for anyone else that comes across the same problem and is also proof just because they are 4pots doesn't mean they are better..


i was planning on using them on my 312mm discs the standard brembo pads that are new and obviously braided brake lines ... running 312mm with oem pads at the moment.