Identify These Ap Calipers

[gtr fan]

Can anyone identify these AP calipers?

I am looking to use on the rear of R32 GTR but the seller can't provide any further details (part number etc). Just the following;

AP racing brake caliper Mounting holes spacing center to center hole 3 1/2" Piston diameter 1 7/8" and 1 3/4"

Anyone know if they would be suitable when used with 6 pistons on the front?

[SiR_RB]

im guessing you might have to get some brackets made up to run these? unless the previous owner had these on an r32 gtr?

[gtr fan]

Yeah i was expectting brackets will be required.

No not previously on gtr

[Roy]

No way you can run these on the rear. The piston sizes mean you would most likely not be able to run them on the front properly as you would end up with a massive bias increase on the front. Also being lug mount means they are not very adapatable to an installation....even if they are dirt cheap....they wont do what you want them to do

[gtr fan]

Thanks Roy,

I was hoping you would reply as you seem to be an expert in this area from what I read on previous threads.

I will happily let these pass then.

Regards,

Rohin

[Roy]

When looking at them just remember that piston sizes and rotor diameter are what you need to generally consider.

Std an R34/34 GTR has 324mm rotor and 44/38mm pistons in the Brembo caliper. So increasing the rotor diameter increases the frontwards bias. If you go for a common upgrade like a Brembo F50 caliper then the piston sizes are 44/40. So the increase in piston sizes again give you a general increase in frontwards brake bias bu increasing the available braking torque.

If you are running a bigger rotor diameter, its not unusual to actually have smaller pistons then std in your caliper. The fact that that AP has pistons larger then an F50 says its not going to be a very good thing in the front....and horrible in the back

[Beer Baron]

yep and not being radial mount makes it even less desirable. pain in the arse to make a decent adapter for a lug mount caliper on the rear. the look pretty old and un-loved too.

[gtr fan]

I can't even tell the difference between mounting styles.

I think they are off a NASCAR. There seems to be lots of used brake setups for sale from NASCAR etc.

Glad I asked here!

[Beer Baron]

see the two little 'lugs'? you want calipers WITHOUT those.

you want radial mount which looks like these below. look at the one on the right (which is upside down). see how it doesn't have those lugs? it has 2 holes in the caliper. then you can use a very simple and neat mount which attaches to the lugs on your hub and provides a easy surface to mount the caliper.

with those you would use a mount that looks like this (which is in fact a bracket to mount some brembo radial mount calipers to a GTR hub):

[gtr fan]

Thanks for the tip Richard.

This issue didn't even occur to me. But now its easily identifiable.

[T04GTR]

wow. they are some oold calipers. being lug mount makes them as good as usless. and from the look of them its sub 300mm disc fitment. front application.