ap uprated front brakes

[Robin C]

Does anybody know the specification of the callipers and discs used in the ap uprated brake kit?

 

 

[edmandsd]

These are items specifically commissioned by Caterham Cars i.e. You won't be able to purchase these items from ap or any of their distributors directly. Same with the uprated master cylinder.

[PAUL MARRIOTT]

I've just bought the AP kit and have been advised by Caterham that I will not need the master cylinder upgrade? Has anybody done both? If so would they support Caterhams comment.

 

Paul M.

 

 

 

[Peter Carmichael]

The MC upgrade is a strange one. An MC has very few performance parameters. Diameter of bores is one. Latency is the other.

 

Latency is the wasted movement at the top of the pedal travel where the bores are still open to the reservoirs and no line presusre is established. The less the better. AP tend to aim for minimum latency in all their MC designs - in particular, AP's single master cylinders are shimmed individually so that components are not transferrable from one MC to another.

 

The diameter of the race MC is larger than the standard, giving a heavier pedal with shorter movement. For many, the weight increase is too much and it gives the distinct impression that you have no brakes. You can go the whole hog and fit higher friction pads to redress the balance. Calipers with larger piston area also reduce pedal weight, as do larger disks. The race MC is about right with big front brakes, big rear brakes and high friction pads (such as Pagids).

 

The standard brake set up can have problems with the high latency of the rear calipers because of the handbrake mechanism. The race MC will mask this shortcoming, but at the price of heavier pedal weight and is not an ideal solution.

 

 

[Peter Carmichael]

I would upgrade rear calipers first and then upgrade MC and brake pad material at the same time.

 

I am in the middle of doing this, and ran a combination of Mintex 1155 front pads on big brakes and Pagid rears on big brakes with the race MC. The proportioning valve prevented rear end lock up and ultimate braking was effective, but the pedal weight was all wrong. Hopefully fixing all of that tonight.

[Paul Ranson]

I found no problems with pedal weight using the big M/C and AP front/rear calipers, albeit with Mintex1136 pads.

 

Because the pedal feel was both firmer and more reliable I found I was able to brake later (and consequently harder...) with more confidence.

 

But I can see some people not liking the relatively extreme firmness and high pressures required, so YMMV. The only time I drove Peter's car I disliked the brakes, too squidgey, which was either imperfect bleeding (as if!) or down to the then standard M/C.

 

Paul

[Peter Carmichael]

or cold pads because you were driving it on a drag strip...

[DohNut]

Peter

How did you resolve the handbrake issue with uprated calipers?

Did you have to get new alloy ears?

 

Nick

[Paul Ranson]

or cold pads because you were driving it on a drag strip...

 

Does the pedal firm up with use?

 

(I think it's a characteristic of cheap Girling M/Cs)

 

Paul

[PAUL MARRIOTT]

Sounds logical I'll stay with the standard MC and work up from there. The only flaw in your logic Peter, is the Financial Controller showing distinct signs of Miff at present.

 

Thanks

 

Paul M.