disc width

[clive f]

please can anyone tell me what width/ thickness of disc that the AP calipers take,caliper number is 146c
been trying the AP site but it is`nt being very helpful

Edited by clive f on Thursday 16th October 21:58

[brogenville]

I'm afraid I can't help youcwith what the max thickness is, but if it helps then the standard discs are 30mm's.

Ap are normally pretty helpful if you phone them though. How come you're asking anyway?

[Ireland]

Steve Heath ( shpub on here) should be able to answer you as he's been working on a replacement disc kit for the Cerb.

[brogenville]

I spoke to Steve th other day about his brake upgrade- basically there wasnt enough interest to get it off the prototype stage, as he would have needed a few firm orders for it to be worth getting a batch made up.

Its a real shame, because while the 4.2's callipers are decent enough, they're let down by th size of the discs. Steves package was apparently going to come out at about 500 quid, which includes separate discs and bells, so whilst it seems expensive, it will make for very cheap replacement discs in future. If you consider that a set of standard 4.2 discs is over 400 qiod, it seems a no brainer to me.

Dont suppose anyone else would be interested?

[Omerta]

I've been wondering if the 4.2 calipers with bigger discs might be enough to go racing with. How big a disc can the 4.2 calipers accommodate?

The BA Ford Falcon (down under model only, sorry) discs look like they might fit the Cerb. 28mm wide, 5x114.3, 71.8 bore, +35 offset. Standard ones are only 296mm but there are some relatively cheap upgrade options to 330mm.

[Steve_T]

On the 4.5 it's 29.2mm. I have 330x28s AP discs as a replacement for standard on mine and they were fine. You may be able to fit a 30mm disc also.

[Steve_T]

Omerta said:

I've been wondering if the 4.2 calipers with bigger discs might be enough to go racing with. How big a disc can the 4.2 calipers accommodate?

The BA Ford Falcon (down under model only, sorry) discs look like they might fit the Cerb. 28mm wide, 5x114.3, 71.8 bore, +35 offset. Standard ones are only 296mm but there are some relatively cheap upgrade options to 330mm.

Worth mentioning that the inner radius of the 4.2 calipers won't accomodate a 330mm disc, although 4.5 calipers will. This is the max the 4.5 will take, any larger and you need to shave a bit more off them as Brummie has although the 343 he used is a rear disc for a race series I found out when I discussed options with BG Dev. The next step up is 6 pots taking a 355 or 362mm disc, which have the same 152mm mounting centres as the 4 pot so you can just space them out from the standard hub.

[clive f]

brogenville said:

I'm afraid I can't help youcwith what the max thickness is, but if it helps then the standard discs are 30mm's.

Ap are normally pretty helpful if you phone them though. How come you're asking anyway?

the calipers in question are Brummies old ones that he has just replaced, and I will be fitting them onto the front of my griff when I do the AJP engine install this winter.
Brummie wasn`t sure , but reckoned 28-30mm so I just wanted confirmation before I bought the discs, as I have 4 stud hubs I`m looking at ford focus st170, which are 300mm dia, and extremely cheap compared to other options, bells an rotors ect.

thanks for your help

clive

[Brummmie]

There was nothing wrong with the stopping power of the 4.2 setup, plenty of feel and power, it was just that after 4-5 laps they cooked, and the pedal "decked" completely! It was a bit rear biased though as on the brakes it kept wanting to go sideways. I reckon best quality racing fluid/pads and some ducting they could be fine, but as usual i couldnt resist smashing my butterfly with a coal hammer!

[touching cloth]

I had in my head that the 4.2 callipers were physically capable of accommodating discs upto something like 304mm, it is on an old thread somewhere but the search does not go back far enough these days. I'll keep digging, I did a lot of hunting and searching before on how big I could go on 4.2 before ultimately just opting to go up to the 4.5 callipers and Tuscan S discs.

[brogenville]

Its interesting you say that TC, as when looking for discs the other day, I noticed that racing green specify a 291mm disc for early 4.2s, and a 304mm ( which is, I believe, still smaller than a standard 4.5 disc) disc for late 4.2's. Assuming that all 4.2's then, regardless of age, had the same basic calliper (bar he odd cosmetic difference) then I suppose it shows that a 4.2's callipers should take 304mm discs.

Not only that, but the bigger discs were significantly cheaper than the smaller ones.

So, is there any truth in what I'm assuming? Does anyone know if late 4.2's had a different disc, and if so, did they also have a different calliper mounting bracket?

[touching cloth]

Hmmn, equally I could be remembering 304 then from the later spec, I think there was indeed a change in caliper when they switched to the ones that came as standard in black with the yellow writing on, maybe only they can take upto 304

[brogenville]

Looking through some old threads, it does look as if 4.2 callipers will take 304mm discs, and at £260 its a lot easier to swallow than £400.

Presumably the offset on these discs would be the same as the 291mm discs?

[tuscan_al]

I had similar issues with my tuscan. It had late cerb calipers from 4.5 and some 4.2's They are the AP CP5200 which can be identified with the three allen bolts on either side of the pad holding the caliper together. The original tuscan came with same 291mm discs, this was soon brought upto 304mm using a small spacer on the mounting bracket by TVR. The caliper looking at ap web site will take upto a 330mm x 30mm disc, so that what im now running on a bells and rotor setup. Just had some spacers made to 22mm to bring out the caliper from the 304mm size less the 8mm iirc spacer that was fitted. So basically its hub 22mm spacer caliper. But if you have these discs you can run 330mm x 30. Other calipers look quite different. The later sags etc then went with CP6600 calipers which have a different mounting space something like 162mm between bolts instead of 154mm.

Hope this ramble helps?!