[///MPhatic]

In an effort to possibly avoid scoring my new wheels with the bigger 2NH calipers, I'm looking for pictures that show where the stones normally get trapped and cause damage to the caliper and wheel.

My thought process is that I may be able to remove a bit of the 2NH caliper material to keep the scoring from happening because the caliper is extremely beefy, but not knowing where the damage is occurring means I'm just guessing.

If you have any pictures of your damaged 2NH calipers, I would appreciate you posting them. Or if you know where the problem lies, I would appreciate your input, or thoughts in general about how to keep this from happening.

Thanks in advance for any input.

[bruiser135msport]

G’day
One of our Compatriots in Sydney extensively tracks his M2 C with 2NH Brakes on multiple occasions every weekend and reports nil issues whatsoever.

I have a M2 CS and no problems also .

Whilst it’s possible I’d say it’s very rare unless your driving on gravel roads or “off piste” .

Cheers
Bruce

[EtotheD]

I'm somewhat in the same boat as I'll be mounting BBS FI-R wheels this summer. I recently swapped over from the silver to red 2NH. Had one score on the drivers side lower end of caliper and small nicks on the upper part. With the way the wheel is spinning it looks like the lower is the most common entry point. It left a light 6" scratch on my 788M wheel.

Taking material off is one way but how much? The clearance is so tight already it would take quite a bit. Then there is the possibility of an even larger rock getting wedged in there. Custom caliper bracket to go down to a 380mm rotor would be nice or some sort of deflector on the bottom maybe? I feel like I might just end up biting the bullet and taking the risk if I don't come up with something.

[ZL9M2]

Some sort of scraper I think would be the best idea. We use scrapers on the front hubs in our motocross program. Slower speeds on roads that have some gravel create the problem. I have one scored wheel on the CS.

[///MPhatic]

Originally Posted by bruiser135msport

G’day
One of our Compatriots in Sydney extensively tracks his M2 C with 2NH Brakes on multiple occasions every weekend and reports nil issues whatsoever.

I have a M2 CS and no problems also .

Whilst it’s possible I’d say it’s very rare unless your driving on gravel roads or “off piste” .

Cheers
Bruce

Bruce,

Thanks for your reply. However, I have spoken with many people regarding this, and the problem is very common, and certainly not limited to gravel roads. Some of these owners' cars have never seen gravel or rain. So I would count yourself lucky.

Originally Posted by EtotheD

I'm somewhat in the same boat as I'll be mounting BBS FI-R wheels this summer. I recently swapped over from the silver to red 2NH. Had one score on the drivers side lower end of caliper and small nicks on the upper part. With the way the wheel is spinning it looks like the lower is the most common entry point. It left a light 6" scratch on my 788M wheel.

Taking material off is one way but how much? The clearance is so tight already it would take quite a bit. Then there is the possibility of an even larger rock getting wedged in there. Custom caliper bracket to go down to a 380mm rotor would be nice or some sort of deflector on the bottom maybe? I feel like I might just end up biting the bullet and taking the risk if I don't come up with something.

Thank you so much for this post. I think it was your calipers I had seen the pictures of. The custom bracket and smaller front rotor sounds like the sure ticket.

I think taking the risk with normal wheels would probably be fine, especially if the barrel is silver and the scores are hardly noticeable. However, my BBS FI-R wheels are Diamond Black, which have a dark barrel, and BBS recommends replacement if the score is 1mm deep, so I am unable to take the risk.

Originally Posted by ZL9M2

Some sort of scraper I think would be the best idea. We use scrapers on the front hubs in our motocross program. Slower speeds on roads that have some gravel create the problem. I have one scored wheel on the CS.

Great idea, I had not heard of it before. Do you have a picture of said scraper?

[EtotheD]

Originally Posted by ///MPhatic

Thank you so much for this post. I think it was your calipers I had seen the pictures of. The custom bracket and smaller front rotor sounds like the sure ticket.

I think taking the risk with normal wheels would probably be fine, especially if the barrel is silver and the scores are hardly noticeable. However, my BBS FI-R wheels are Diamond Black, which have a dark barrel, and BBS recommends replacement if the score is 1mm deep, so I am unable to take the risk.

My FI-R are diamond black as well. 1mm is such a low tolerance, they are fairly thin wheels though. Racing Brake was the only one I found who sells a kit to downsize to a 380mm up front but it's the whole set. I don't think they'll sell just the bracket. Not sure if it would be compatible with a OG 380 x 30 rotor. Toyed with the idea of sticking some sort of foam adhesive pad in that area but haven't found anything that would for sure stick. I think some have used foil tape on wheel weights to keep then on during track events. I was thinking if you stack enough in that area you can close the gap and keep rocks out. The gap is so small it wouldn't take much.

[///MPhatic]

Originally Posted by EtotheD

My FI-R are diamond black as well. 1mm is such a low tolerance, they are fairly thin wheels though. Racing Brake was the only one I found who sells a kit to downsize to a 380mm up front but it's the whole set. I don't think they'll sell just the bracket. Not sure if it would be compatible with a OG 380 x 30 rotor. Toyed with the idea of sticking some sort of foam adhesive pad in that area but haven't found anything that would for sure stick. I think some have used foil tape on wheel weights to keep then on during track events. I was thinking if you stack enough in that area you can close the gap and keep rocks out. The gap is so small it wouldn't take much.

Some sort of black tape with metal properties might actually work. Probably have to get the wheel balanced afterwards.

It's interesting that your thinking is that the gap is too big, allowing rocks to stick in there. I never thought of it that way. I guess there is a zone there; too much gap is obviously fine, and almost no gap is fine, but precisely the gap we have isn't fine.

[M Fifty]

How about using different brackets so you can run the standard size discs with the uprated calipers?

[EtotheD]

Originally Posted by ///MPhatic

Some sort of black tape with metal properties might actually work. Probably have to get the wheel balanced afterwards.

It's interesting that your thinking is that the gap is too big, allowing rocks to stick in there. I never thought of it that way. I guess there is a zone there; too much gap is obviously fine, and almost no gap is fine, but precisely the gap we have isn't fine.

I was actually thinking of putting the foil tape on the caliper itself in the lower section. Stacking it enough to close the gap. Whether it works or not is one thing. Tiny road grit might get caught in there but could deflect stones from entering. Defnitely opening the gap is the true solution.

[///MPhatic]

Originally Posted by M Fifty

How about using different brackets so you can run the standard size discs with the uprated calipers?

I'm far from a brake guru so I'm not sure the standard discs will work with the 2NH caliper.

[///MPhatic]

OK, so I think I've found the motherload thread about this...from 2015.

https://f80.bimmerpost.com/forums/sh....php?t=1107233

And apparently there has never never been any attempt from BMW to fix the issue, even though multitudes of owners have had this problem (and CCB owners, not just standard 2NH owners).

Also interesting is that many manufacturers have this problem, but Pagani and Koenigsegg are the only ones to put forth a solution.

[ZL9M2]

Originally Posted by ///MPhatic

Bruce,

Thanks for your reply. However, I have spoken with many people regarding this, and the problem is very common, and certainly not limited to gravel roads. Some of these owners' cars have never seen gravel or rain. So I would count yourself lucky.



Thank you so much for this post. I think it was your calipers I had seen the pictures of. The custom bracket and smaller front rotor sounds like the sure ticket.

I think taking the risk with normal wheels would probably be fine, especially if the barrel is silver and the scores are hardly noticeable. However, my BBS FI-R wheels are Diamond Black, which have a dark barrel, and BBS recommends replacement if the score is 1mm deep, so I am unable to take the risk.



Great idea, I had not heard of it before. Do you have a picture of said scraper?

This is the simple design of the MX scraper. It clears the inner wheel of gunk before rotating into the caliper. Totally different application, but the idea would be to design something that could be mounted to the M2 front hubs to accomplish the same results.

[jdubm2c]

Originally Posted by ///MPhatic

Some sort of black tape with metal properties might actually work. Probably have to get the wheel balanced afterwards.

It's interesting that your thinking is that the gap is too big, allowing rocks to stick in there. I never thought of it that way. I guess there is a zone there; too much gap is obviously fine, and almost no gap is fine, but precisely the gap we have isn't fine.

The gap zone as described here _is_ the issue. The funny thing is that I mounted AP racing brakes in the front, and dropped to 18" wheels. Now I have no issue on the fronts, but the back gap has dropped right into this zone by going to 18's. It is very bad, and I would love to find a solution. Something that keeps them from getting into the wedge area seems doable, and there are some ideas posted that I will have to try out.

[tropicatango]

The 788m oem wheels have barely no clearance with the 2NH

I change wheels to titan7 ts5 and there is a lot more clearance

[///MPhatic]

Originally Posted by ZL9M2

This is the simple design of the MX scraper. It clears the inner wheel of gunk before rotating into the caliper. Totally different application, but the idea would be to design something that could be mounted to the M2 front hubs to accomplish the same results.

Absolutely. I sense a business opportunity for someone, and a good one. This issue has been around in the BMW world since at least 2015, and I'm sure in the Porsche world for many years before that.

I'm still buying a set of 2NH, but won't fit them until I find a solution. What you've shown me seems like something that could be 3D printed quite easily.

Originally Posted by tropicatango

The 788m oem wheels have barely no clearance with the 2NH

I change wheels to titan7 ts5 and there is a lot more clearance

It's the same with the 437 and 763, and the same (no issue) with BC Forged KL01 and KL11, no issues there at all, the barrels are made for larger brakes.

[ZL9M2]

That's what I thought. 3D print a part that would extend into the barrel of the wheel to divert the small stones that are the issue. Somehow mounted off the pinch bolt area?

[///MPhatic]

Originally Posted by ZL9M2

That's what I thought. 3D print a part that would extend into the barrel of the wheel to divert the small stones that are the issue. Somehow mounted off the pinch bolt area?

Yes, absolutely. Or even lower somehow.

[ZL9M2]

Yeah, but the stones must enter from the top given the forward rotation of the wheel. Mounting something towards the top of the wheel barrel just in front of the caliper there would be the ticket. You would almost have to mount it via the lower pinch bolt or design something that would mount around the bottom of the shock.

[///MPhatic]

Originally Posted by ZL9M2

Yeah, but the stones must enter from the top given the forward rotation of the wheel.

Hmmm. I figured the stones were in the lowest part, then at the wheel turns they get caught up. Maybe I get that idea from the lower parts of the caliper always damaged more?

[EtotheD]

Just throwing some ideas around. Possibly use the brake line as a mounting point. Cut some thin ABS sheet similar to DIY mud flaps. Put some holes to secure it behind and onto the brake line with zip ties. Would take some trial and error but could work. Excuse my terrible attempt at a Microsoft Word drawing.

[///MPhatic]

Originally Posted by EtotheD

Just throwing some ideas around. Possibly use the brake line as a mounting point. Cut some thin ABS sheet similar to DIY mud flaps. Put some holes to secure it behind and onto the brake line with zip ties. Would take some trial and error but could work. Excuse my terrible attempt at a Microsoft Word drawing.

I think this could work for sure. I wish I knew the proper name for this, like what Pagani calls it, just so I could search for more pictures to see how they did it. My searches come up with nothing though.

[agent_orange]

Finally a constructive thread here about this, not just 'it's a myth lolz'.

I've got 2 scatches like the second picture from EtotheD on my left side caliper, and 3-4 light scratches inside the left 788 wheel. Right side is OK.
Only 3,300km from new, never driven on gravel, never tracked (yet), never driven in rain.

I know that stone scrapers have been pretty much standard on gravel rally cars as long as there have been gravel rally cars with disc brakes and aluminium or magnesium wheels, i.e. over 50 years.
So this doesn't need a 'new' solution.

I've looked at the bottom edge of the front calipers to assess the viability of fabricating some scrapers/deflectors, but it's a tricky shape with no flat surfaces and the crossover pipe going through there too.
Thought about moulding some on the caliper itself with wheel in place using hard-setting liquid polyurethane and temporary dams, then grinding some clearance onto the 'blob' once set.
3D printing some in a high temperature plastic or sintered metal would likely be the best solution, and I don't have the gear for that.