Why are my Kopis binding on the brake pads?

[MR 325]

I don't know about everyone else but my Kopis had tons of room between the caliper and the wheel.

[BMWE34M5]

You may have to use a 10 mm spacer with a BBK.

So Kopis would be a bad choice if somebody is planning on IEs 330mm BBK?

[Kilomph]

So Kopis would be a bad choice if somebody is planning on IEs 330mm BBK?

[Nick325is]

I bent a kopi and the replacement rubbed on the caliper. Turns out the new Kopis are slightly different than the older ones I had. If you look at the inside of the wheel where it bolts to the hub on the old kopis the edge is ground down. On the new ones the edge sticks out farther and rubs on the caliper.
I just ran that wheel on the back of the car and had no problems.


Nick

[DanGillan]

i know what he may be talking about...
i had 4 of Robby's old kopis, those all fit all the time with now problems.
i trashed one on a pothole and ordered a new one from abrahams.
i got it, as soon as i had the tire mounted to it and installed it, the wheel was grinding on the edge of the caliper, it was a very light contact so i let it go until it ground itself into clearance. very very wierd. also the newer kopis dont require a centering ring, while the ones i got from robby do require one.

[rwh11385]

In my original post I stated that when I changed pads, I installed the stock basketweaves. Now I go to put the Kopis back on and I have this. The old pads have been gone for 4 months.

The car sees plenty of track time, I'm not going to order a bunch of track pads to go through and see if they fit. Modifying the Hawk pads took 15 minutes including removal and installation of both wheels and it was free.

modifying pads?

buy hawk hp+ pads from bimmerworld. why wouldn't they fit?

if they don't you did something wrong on the install or maybe have the wrong parts. what ducting kit do you have? bimmerworld might also be able to help here

calling a shop with tons of experience in what you are talking about >> hoping for random forum members to help

also trying Vaughn Motorwerks in Zionsville off 106th and Michigan

[Digitalwave]

I remember that car now... it was that retard 00ronburgandy00's.

Looks a ton better now that it got some TLC.

[MR 325]

I don't know who fuzz is, but the previous owner said he traded some Borbet Ts for the Kopis if I remember correctly.

This guy http://www.r3vlimited.com/board/showthread.php?t=64966 :)

[m20e34]

Compare your old pads to the new ones, see if that is the difference.

Clearance the backing plate of the new pad as needed to prevent rubbing.

or just buy pads that fit.

In my original post I stated that when I changed pads, I installed the stock basketweaves. Now I go to put the Kopis back on and I have this. The old pads have been gone for 4 months.

The car sees plenty of track time, I'm not going to order a bunch of track pads to go through and see if they fit. Modifying the Hawk pads took 15 minutes including removal and installation of both wheels and it was free.

[Jordan]

Compare your old pads to the new ones, see if that is the difference.

Clearance the backing plate of the new pad as needed to prevent rubbing.

or just buy pads that fit.

[m20e34]

So wait.. I was under the assumption the caliper was binding on the back of the spokes... but you are saying the brake pad itself is binding on the inside hub surface of the wheel.... Thats a new one.

Are you sure you've installed everything properly? With this new information I believe something is VERY wrong.

The brake pad backing plate is grazing on the inside hub surface of the wheel right at the very edge of where the wheel hub and brake disc hub meet - because the disc & wheel hubs are not flush, the wheel hub is bigger.

Something very wrong is exactly what I thought, but everything is correct, trust me. The wheel hub should have a smaller diameter, but since no one else has this problem, it can't be the root cause.

The only explanation is that is that the pad backing plates are 1-2mm oversize.

edit: The backing plate is touching on the corner (bottom/outside) to the wheel hub corner (top/inside) so the backing plate could be oversize in height or thickness or both.

[Jordan]

So wait.. I was under the assumption the caliper was binding on the back of the spokes... but you are saying the brake pad itself is binding on the inside hub surface of the wheel.... Thats a new one.

Are you sure you've installed everything properly? With this new information I believe something is VERY wrong.

[m20e34]

Spoilerless 318iS, you shall be the first to do it my man

Those wheels used to belong to fuzz, hehe. The wheels on his car now used to be on your car!

Love the car btw.

I don't know who fuzz is, but the previous owner said he traded some Borbet Ts for the Kopis if I remember correctly.

[m20e34]

The caliper is not touching the wheel in any way, only the pad.

"Binding" is a bad word. Since the pads can be pushed up into the caliper, the wheel was pushing the pad up ever so slightly, maybe a mm. The springs on the top of the pads that push back down to prevent squealing, were pushing the pad down onto the hub of the wheel right at the part where the wheel hub and brake disc hub meet. The wheel hub is bigger, so it makes contact.

I dremeled the backing plate so that at the bottom of the pad, the backing plate matches up with the friction material instead of having overlap. This fixed the problem.

Jordan: Not sure which calipers I have, if I had to guess, I'd say ATE.

[Dave]

aardvarc racing sells 3mm spacers - I think I paid 70 plus ship for the set.