[MooMooM2]

its not a myth. I have 3 sets of wheels, 788, 641 and even some Apex EC7 and they all have scratches in the barrel from a stone getting stuck. Even the EC7 which actually have decent clearance.

[ZL9M2]

The scraper needs to be somewhere near the top of the caliper or the top inside of the wheel barrel. As the small stones deposit into the wheel barrel they rotate back and up with the wheel and then squeeze between the top of the caliper and the wheel. I'm going to see what I can come up with without access to a 3d printer.

[///MPhatic]

Originally Posted by agent_orange

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.


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.

I had no idea, thanks for that tidbit.

I honestly don't think it needs to be something strong, we're just talking about small stones here, even something weak and flexible should do the trick, don't you think?

Originally Posted by ZL9M2

The scraper needs to be somewhere near the top of the caliper or the top inside of the wheel barrel. As the small stones deposit into the wheel barrel they rotate back and up with the wheel and then squeeze between the top of the caliper and the wheel. I'm going to see what I can come up with without access to a 3d printer.

I understand this logic now, I was missing it before. The stone isn't entering and then moving up immediately, it's getting into the wheel, bouncing around and then moving inwards before rotating up and into the bottom of the caliper, correct? If so, I still think the guard should be on the bottom, no? What am I missing?

[agent_orange]

Definetly guard on the bottom on this application.
With the front calipers being behind the hub centreline, the leading edge of the caliper is the bottom.
This is where the scratches happen from stones making the short trip from sitting on the bottom of the wheel barrel up into the gap with the caliper when driving forwards.
On other cars with the caliper on the front of the hub (or rear brakes on these cars), the stones would have to go the long way all around to get stuck in the caliper gap, so probably a bit less likely.

[EtotheD]

I went ahead and tried my previously proposed design. Ordered a 1/16" thick ABS sheet from Amazon. Cut the shape and marked the brake lines to drill the holes for zip ties. I had to cut more off after putting the wheel on and seeing the fitment. Basically the position of the brake lines, drilled hole position, and taper of the wheel barrel all affect it. It wasn't the same for both sides. Overall I think it came out pretty good and solid. Now to see if it actually holds up and works, only time will tell.

[FaRKle!]

That's a pretty nifty plate! ABS should hold up pretty well for street driving. It won't hold up to the heat of the track since it deforms around 150-300F (depending on the type of ABS).

One other idea could be to taper the ABS scraper/plate so the pebbles naturally run off (similar to how snow plows are angled).

[(K)]

That's quite clever. A fantastic job overall with this thread, the collective brainpower of this community is amazing. Much like the custom intake snorkel thread, I will be more than happy to support or donate to this project if something comes out of it.

[///MPhatic]

Originally Posted by EtotheD

I went ahead and tried my previously proposed design. Ordered a 1/16" thick ABS sheet from Amazon. Cut the shape and marked the brake lines to drill the holes for zip ties. I had to cut more off after putting the wheel on and seeing the fitment. Basically the position of the brake lines, drilled hole position, and taper of the wheel barrel all affect it. It wasn't the same for both sides. Overall I think it came out pretty good and solid. Now to see if it actually holds up and works, only time will tell.

You are a God among men sir. I'll be the first to purchase a set from you!!

[speedsnice]

I would be down for a set of scrapers.

[///MPhatic]

Originally Posted by speedsnice

I would be down for a set of scrapers.

Hopefully we can get something going. I'm not installing the 2NH with my FI-R's until we do.

[EtotheD]

Including my base template measurements if anyone wants to try it out. Unfortunately this method requires customization because fitment will be different for everyone. A 12x12 1/16" ABS sheet is only around $7 on Amazon. It can easily be cut with a utility knife and a straight edge. Mark your drill points after fitting it behind your brake lines. Zip tie on and mount wheel to check fitment. Clip zip ties off to remove and take off material as needed. Will all depend on wheel barrel shape. Took me about 3 tries on each side.

I feel like it's going to be difficult to prove that any solution works. Unless someone wants to put on a scraper design and go crazy on a gravel road haha. Still I figure the more people that try it the sooner we'll know if it's somewhat viable. The M2 isn't my daily so it would take me some time to assess.

[///MPhatic]

Originally Posted by EtotheD

Including my base template measurements if anyone wants to try it out. Unfortunately this method requires customization because fitment will be different for everyone. A 12x12 1/16" ABS sheet is only around $7 on Amazon. It can easily be cut with a utility knife and a straight edge. Mark your drill points after fitting it behind your brake lines. Zip tie on and mount wheel to check fitment. Clip zip ties off to remove and take off material as needed. Will all depend on wheel barrel shape. Took me about 3 tries on each side.

I feel like it's going to be difficult to prove that any solution works. Unless someone wants to put on a scraper design and go crazy on a gravel road haha. Still I figure the more people that try it the sooner we'll know if it's somewhat viable. The M2 isn't my daily so it would take me some time to assess.

Thanks for the diagram. I plan to work on this when I get my 2NH set.

[///MPhatic]

Originally Posted by speedsnice

I would be down for a set of scrapers.

I have sent RacingBrake a question about the availability/price of the AD702 adapters, and which pads would be required. Fantastic catch on this man, much appreciation.

For those of reading this that don't know what we're talking about, RacingBrake.com makes a kit to fit the big 2NH caliper to the 380mm rotors using a AD702 adapter.

https://racingbrake.com/bmw-irp-04/

[///MPhatic]

Dead end.

"We DO NOT sell adaptors separately like other job shops would to ensure caliper/rotor/pad compatibility.
If you want a brake pro's opinion - This is the only and best solution w/o impairing the system integrity.
Otherwise you maybe able to source the adaptors from other job shops and retrofit with a rotor at your own discretion.
Thank you for your understanding.

Team RB"

[speedsnice]

I ordered a set of 20 inch BBS LM’s but then came to my senses and cancelled the order. My OEM wheels have multiple stripes inside the barrels and one of my BBS FI-R’s got a light stripe (repaired by Proformance Industries) and the other wheel has marks from stones getting caught and being ejected before causing stripes.
I am really tempted to just order the Racing Brake 2 piece rotors with adapters, Racing Brake stated you can use any pad that works with the OEM rotors and don’t have to use a proprietary pad from them.

[///MPhatic]

Originally Posted by speedsnice

I ordered a set of 20 inch BBS LM’s but then came to my senses and cancelled the order. My OEM wheels have multiple stripes inside the barrels and one of my BBS FI-R’s got a light stripe (repaired by Proformance Industries) and the other wheel has marks from stones getting caught and being ejected before causing stripes.
I am really tempted to just order the Racing Brake 2 piece rotors with adapters, Racing Brake stated you can use any pad that works with the OEM rotors and don’t have to use a proprietary pad from them.

I honestly feel like if we could talk to the right people we could get a set of adapters made that would fit the 2NH to the 380/30 front rotor without issue. I'm researching the additional 6mm piston issue now, like could we just replace the pistons with 6mm longer ones? We're not talking about a lot here, just 6mm. And maybe we wouldn't need all 6mm, maybe 3mm would do the trick without failure. It's a brake specialist we need.

I have a few weeks to sort the issue out before the set of 2NH brakes I want become for sale. If I can't figure it out I'm going to have to let them go, as I can't risk my FI-R's for brakes.

[///MPhatic]

OK, so I just got off the phone with my brake guru, and he said the following.

The blue brake rotor being 6mm smaller in thickness (30mm) vs the 2NH rotor (36mm) isn't an issue, as a 6mm spacer could be fashioned to fit on the back of the pad, or over the pistons on the inside easily. RacingBrake probably doesn't want to sell this part because of liability (not from the first owner, but if the car is ever sold).

He also thinks that the 10mm difference in OD between the standard rotor (380mm) and the 2NH rotor (400mm) is probably not an issue either, as the mounting bracket (adapter) could probably be modified fairly easily, but RB doesn't want to sell it separately because of liability. And it's possible that their rotors are made with a slightly smaller hat so there is no pad intersection.

His advice was to go with the racing brake solution above, but since I want to use the OEM rotors, $2181 is a bit much for adapters.

[speedsnice]

Originally Posted by ///MPhatic

OK, so I just got off the phone with my brake guru, and he said the following.

The blue brake rotor being 6mm smaller in thickness (30mm) vs the 2NH rotor (36mm) isn't an issue, as a 6mm spacer could be fashioned to fit on the back of the pad, or over the pistons on the inside easily. RacingBrake probably doesn't want to sell this part because of liability (not from the first owner, but if the car is ever sold).

He also thinks that the 10mm difference in OD between the standard rotor (380mm) and the 2NH rotor (400mm) is probably not an issue either, as the mounting bracket (adapter) could probably be modified fairly easily, but RB doesn't want to sell it separately because of liability. And it's possible that their rotors are made with a slightly smaller hat so there is no pad intersection.

His advice was to go with the racing brake solution above, but since I want to use the OEM rotors, $2181 is a bit much for adapters.

The Rotors Racing Brake has in the kit are great quality 2 piece rotors and have been used in Motorsport for some time now. My OCD won’t allow me to order the fronts alone, I might order the kit with all 4 rotors. Too bad the G80 rotors have a different bolt pattern, they are 380x36mm

[///MPhatic]

Originally Posted by speedsnice

The Rotors Racing Brake has in the kit are great quality 2 piece rotors and have been used in Motorsport for some time now. My OCD won’t allow me to order the fronts alone, I might order the kit with all 4 rotors. Too bad the G80 rotors have a different bolt pattern, they are 380x36mm

Some older bad press, but I suppose they have addressed the issue.

https://forums.nasioc.com/forums/sho....php?t=2614743

If you order them I'd like to see the specs on their adapter.

[speedsnice]

Originally Posted by ///MPhatic

Some older bad press, but I suppose they have addressed the issue.

https://forums.nasioc.com/forums/sho....php?t=2614743

If you order them I'd like to see the specs on their adapter.

That’s the only issue I have found, it was a CTS-V that was Track driven. On a GM forum someone commented that it was an older version of the 2 piece rotor. I also found a post about a BBS FI-R failing on the track after it was powder coated, it did not keep me from getting the FI-R’s.

I found photos online of the OEM Caliper bracket and the one from Racing Brake. It doesn’t look like the factory bracket can be machined.

[///MPhatic]

Originally Posted by speedsnice

That’s the only issue I have found, it was a CTS-V that was Track driven. On a GM forum someone commented that it was an older version of the 2 piece rotor. I also found a post about a BBS FI-R failing on the track after it was powder coated, it did not keep me from getting the FI-R’s.

I found photos online of the OEM Caliper bracket and the one from Racing Brake. It doesn’t look like the factory bracket can be machined.

That thread has 2 cars that had the same issue, and I did find others, but I'm sure they were an older version. It doesn't really matter to me because I'm wanting the OEM look.

I wasn't going to have the factory bracket re-worked, I was going to have my brake guy machine me new brackets.

[///MPhatic]

Originally Posted by EtotheD

I went ahead and tried my previously proposed design.

Is this solution working for you?