Dumb questions on brakes

[4Y_stack_acceleration]

Really tried to search/Google these so apologies in advance.

1. My car was spec'd with 19" wheels. Everything is currently stock. I am planning to go down in diameter to 18" aftermarket wheels for a square setup. Do I need to get smaller rotors than stock to fit smaller rims?

2. Any issues mixing and matching rotors front (2-piece floating girodiscs) and rear (OEM rotors)?

[RugbyBro]

1. If you're on base brakes (non-CCB) then you'll be fine with a 18in square setup, just confirm before hand that the barrels have enough space or stick with brands that make 18s for the F8X market (Bimmerworld, Apex, Titan7, etc.). Relevant info on square setups here: https://f80.bimmerpost.com/forums/sh....php?t=1555419

2. No issues, with TC off you'll use the rears a lot less than with it on or in MDM.

[Suds]

F80/82 M’s were sold with 513m 18” rims as the base option.
I have a square set of rears I have used on the track on 3 different F8x M cars.
513m’s on my M2.

[Track/S]

Best R18 options for F8X
513M both in 10.5 and 10.0.
For more aggressive setup 763M 11"

[4Y_stack_acceleration]

Originally Posted by RugbyBro

1. If you're on base brakes (non-CCB) then you'll be fine with a 18in square setup, just confirm before hand that the barrels have enough space or stick with brands that make 18s for the F8X market (Bimmerworld, Apex, Titan7, etc.). Relevant info on square setups here: https://f80.bimmerpost.com/forums/sh....php?t=1555419

2. No issues, with TC off you'll use the rears a lot less than with it on or in MDM.

Thank you. Between girodiscs and OEM rotors, how much longer do girodiscs last for (# of track days)?

I personally don't need the weight savings and I've read there's no difference in braking performance, but I haven't read a clear answer on wear life from other threads and whether the 'cost per track day' is better or worse than OEM rotors considering these cost more than twice as much.

[Montaver]

Originally Posted by 4Y_stack_acceleration

Thank you. Between girodiscs and OEM rotors, how much longer do girodiscs last for (# of track days)?

I personally don't need the weight savings and I've read there's no difference in braking performance, but I haven't read a clear answer on wear life from other threads and whether the 'cost per track day' is better or worse than OEM rotors considering these cost more than twice as much.

Giros will easily last more than double OEM, they are seriously durable. OEM disks will be cracking from the holes after one weekend, I know this from my M2C which has bigger discs than a regular f8x. The hats on Giro are also reusable. Different (and lighter) platform but I got 25+ days out of a set of fronts on my old GT4 and they were not done. There is a reason everyone uses them.

[mike082802]

Originally Posted by 4Y_stack_acceleration

Thank you. Between girodiscs and OEM rotors, how much longer do girodiscs last for (# of track days)?

I personally don't need the weight savings and I've read there's no difference in braking performance, but I haven't read a clear answer on wear life from other threads and whether the 'cost per track day' is better or worse than OEM rotors considering these cost more than twice as much.

Since you're in NY, fcp is close. Buy a set of oem rotors once and you have lifetime replacements. shipping is cheap since you're close to CT. Get rid of your dust shields and get some titanium shims. Once you get too fast and are wrecking them then upgrade to a proper BBK like alcon, AP, or stoptech.

[4Y_stack_acceleration]

Originally Posted by mike082802

Since you're in NY, fcp is close. Buy a set of oem rotors once and you have lifetime replacements. shipping is cheap since you're close to CT. Get rid of your dust shields and get some titanium shims. Once you get too fast and are wrecking them then upgrade to a proper BBK like alcon, AP, or stoptech.

I thought FCP is no longer doing the warranty but store credit instead? Though still better than buying the rotors from the shop.

[m5_mbb7]

Originally Posted by Montaver

Giros will easily last more than double OEM, they are seriously durable. OEM disks will be cracking from the holes after one weekend, I know this from my M2C which has bigger discs than a regular f8x. The hats on Giro are also reusable. Different (and lighter) platform but I got 25+ days out of a set of fronts on my old GT4 and they were not done. There is a reason everyone uses them.

This is not my experience at all. OEM rotors for the 2NH brakes are plenty durable; unless you’re hitting ABS constantly and cooking the brakes or maybe if you’re tracking on a very brake heavy track like COTA, you shouldn’t be cracking them after a weekend.

[RugbyBro]

Originally Posted by 4Y_stack_acceleration

Thank you. Between girodiscs and OEM rotors, how much longer do girodiscs last for (# of track days)?

I personally don't need the weight savings and I've read there's no difference in braking performance, but I haven't read a clear answer on wear life from other threads and whether the 'cost per track day' is better or worse than OEM rotors considering these cost more than twice as much.

I think it depends how fast you are - however lots of very fast individuals i know and have seen run them with their stock calipers. I currently reach the thermal capacity of the stock discs/calipers by the end of every session, however, I am not fast enough to quantify how much longer the Giros will last over OEM. My rotors will likely last thru the rest of the season… I hope lol. Then after that I’ll swap on some Girodiscs along side my new, “upgraded” calipers (SS pistons, high temp seals).