[doughboy]

Ben, i have the standard brakes and a gravel drive, the only issue i have is stones getting between the disc and the heat shield, makes a hideous screaching noise till you back up and it pops out.

UK roads are covered in stones and rubbish, when was the last time you saw a road sweeper? Used to be a common sight.

If find when parking with warm sticky PSS tyres they pick up stones and grit. Then when you next move off they drop off at the top and fall in the wheel area. Pinging and clunking their way out like stones in a washing machine....

My previous M6GC with PSS suffered the same problem.

Other vehicles we have with "normal" tyres don't have this issue at all.

Not much help to you but i can't imagine BMW being sympathetic at all with this. Makes me glad i went for the (more than adequate) standard brakes...

[MMMBRAP]

Can we get some context as to what wheels this is happening with, or if it's just happening with ANY OEM wheel fitted with the stock brakes?

[pz619]

Originally Posted by MMMBRAP

Can we get some context as to what wheels this is happening with, or if it's just happening with ANY OEM wheel fitted with the stock brakes?

Probably all, keep in mind there are some 19 inch wheels that don’t fit because of the huge brakes. It just comes with the territory. The clearance between the brakes and wheels is tiny. So the only way this gets solved is larger wheels like 20s or smaller brakes.

[gnx]

M437, M788 and M763, all front.

[doughboy]

There's loads of threads about this since 2015 with M3/4 CCB brakes and 19" wheels which are the same caliper as Msport BBK.

Another example of manufacturer ignoring it as the cost to change / admit fault is greater than a tiny % of claims.

The gap is tiny, like 3-5mm.

So were talking about tiny road stone peices getting stuck, not pebbles.

[eeyang92]

Originally Posted by doughboy

There's loads of threads about this since 2015 with M3/4 CCB brakes and 19" wheels which are the same caliper as Msport BBK.

Another example of manufacturer ignoring it as the cost to change / admit fault is greater than a tiny % of claims.

The gap is tiny, like 3-5mm.

So were talking about tiny road stone peices getting stuck, not pebbles.

Yep. Normally the clearance would be large enough for those things to roll about until they fall out. But with the small clearance they'll get stuck and gouge the caliper and barrel.

[Poochie]

Originally Posted by doughboy

There's loads of threads about this since 2015 with M3/4 CCB brakes and 19" wheels which are the same caliper as Msport BBK.

Another example of manufacturer ignoring it as the cost to change / admit fault is greater than a tiny % of claims.

The gap is tiny, like 3-5mm.


So were talking about tiny road stone peices getting stuck, not pebbles.

Forget the stone-etched damage; it's downright scary to have a spinning wheel in which there is such little clearance between the caliper.

[chris719]

These calipers and the CCBs were really probably designed for a 20” wheel. I’m not aware of any other car other than F8x with CCBs that have so little clearance.

[Poochie]

Originally Posted by chris719

These calipers and the CCBs were really probably designed for a 20" wheel. I'm not aware of any other car other than F8x with CCBs that have so little clearance.

That's the only logical explanation; I've taken note of BMW's inclination to err on the side of safety, engineering their vehicles and parts that skews more towards minimum risk or exposure over outright performance.

I can't see them drawing up a blueprint for those calipers and wheels from scratch and not factoring that hazardous clearance issue, unless it was an afterthought for a vehicle it was never actually intended for and just was shoehorned, after the fact.

Maybe I've seen "Final Destination" too many times but the thought of something getting wedge in-between the wheels and caliper at high speeds, possible sending the vehicle into a spin, gives me the chills..

Oh maybe I'm just overthinking it.

[Piets94]

9 days and 280km (175 miles) into ownership got me 2 shiny silver scores on the inner barrel of one of my black 788 fronts.
Touch-up paint and move on. It's going to happen again

[808F90]

Originally Posted by gnx

Not much that can be done, have previously posted this

https://f87.bimmerpost.com/forums/sh....php?t=1594208

Originally Posted by gnx

Not much that can be done, have previously posted this

https://f87.bimmerpost.com/forums/sh....php?t=1594208

I have the same problem! Only 1700 miles in my car.

[Zuzu]

Same issue here after 2,200 kms.. NS front wheel

Car with dealer now as scoring is so deep, it affects the integrity of the wheel.

Trying to get resolution with BMW on replacement.. really friggen annoying to be honest.

[chris719]

Originally Posted by Zuzu

Same issue here after 2,200 kms.. NS front wheel

Car with dealer now as scoring is so deep, it affects the integrity of the wheel.

Trying to get resolution with BMW on replacement.. really friggen annoying to be honest.

So, is this really a safety concern, or just cosmetic? You think there would be more noise from owners if this were really a safety issue.

[Zuzu]

Originally Posted by chris719

So, is this really a safety concern, or just cosmetic? You think there would be more noise from owners if this were really a safety issue.

Can be a safety concern depending on how deep the scoring is.
Dealer was concerned at the depth of the scoring and had the wheel scoring measured against the manufactures limitations.
Scoring was within the safety guidelines and Dealer is has sent the wheel away to be repaired.

[chris719]

Originally Posted by Zuzu

Can be a safety concern depending on how deep the scoring is.
Dealer was concerned at the depth of the scoring and had the wheel scoring measured against the manufactures limitations.
Scoring was within the safety guidelines and Dealer is has sent the wheel away to be repaired.

I am impressed both that they measured it and there is actually a spec. Must be nice living in a civilized place. In the US, they would probably refuse to do anything or make you pay for it.

Interested when you get it back if they tell you what type of repair it was. I would assume it's just paint? If they welded it or something I'd be shocked.

[Zuzu]

Originally Posted by chris719

I am impressed both that they measured it and there is actually a spec. Must be nice living in a civilized place. In the US, they would probably refuse to do anything or make you pay for it.

Interested when you get it back if they tell you what type of repair it was. I would assume it's just paint? If they welded it or something I'd be shocked.

Definitely..
This was all done by the dealer as a sign of good will for myself, as a long standing customer of 30 years with many past purchases.

From what I understand, the groove will be filled in, just like a normal gutter rash rim repair, and then milled before repainting.

Will let you know of the finished product once I get the car back.. has been with dealer for 6 days so far.

[Carrera2RS]

I wonder if there is a retrofit mod that could reduce the likelihood, maybe a shield that provides internal cover and ducts air to the callipers (with grills obviously!) be good to understand if there is a genuine safety risk or it’s a frustrating cosmetic issue

[KevinC]

[Zuzu]

Originally Posted by chris719

I am impressed both that they measured it and there is actually a spec. Must be nice living in a civilized place. In the US, they would probably refuse to do anything or make you pay for it.

Interested when you get it back if they tell you what type of repair it was. I would assume it's just paint? If they welded it or something I'd be shocked.

Hi Chris,
Picked up the M today and the wheel is as good as new.
The score has been filled in and machined and the inside wheel rim repainted..
All good now until next time ..

[chris719]

Originally Posted by Carrera2RS

I wonder if there is a retrofit mod that could reduce the likelihood, maybe a shield that provides internal cover and ducts air to the callipers (with grills obviously!) be good to understand if there is a genuine safety risk or it’s a frustrating cosmetic issue

It would be hard. If you try to close the gap further, it would have to be with some kind of shim that somehow is securely mounted to the caliper and can withstand the high temperatures. I'm not sure if that fixes the problem either, just changes what size stone can get trapped. It could probably be done, but I doubt anyone would spend the time and effort needed to machine and test.

[chris719]

Originally Posted by Zuzu

Hi Chris,
Picked up the M today and the wheel is as good as new.
The score has been filled in and machined and the inside wheel rim repainted..
All good now until next time ..

Have them weld in a diamond strip next time, then you can show the rocks who's boss .

[Zuzu]

Originally Posted by chris719

Have them weld in a diamond strip next time, then you can show the rocks who's boss .

Lol..

Actually I saw a post in a chat room a while back, but now cant find, where they where talking about fitting a thin Kevlar strip to the top of the caliper to reduce the gap and hopefully minimize the chances of this happening

Cheers