Track forum general chit chat.

[kyippee]

Rotora US is still alive in the LA area. I got a front & rear BBK used for a price I couldn't resist, and have been running it on track for 3 years (with 1 caliper rebuild in 2019) while buying pads from them.

Also surprised they're around as I never see their parts on cars

[derbo]

Originally Posted by XKxRome0ox

for daily+track use? mostly daily?

My car isn't a daily but it will most likely be driven to the track on its own legs.

[chocstraw]

anyone else have a crippling tire addiction? I'm looking for low-cost alternatives as I don't really push my car too hard on the street, and have a set of Supercar 3Rs for the track.

I've been using Firestone Indy 500s for the street for a while now, I like Bridgestone sidewalls, but I'm barely 9 months on my rears and they're starting to cord (skidpad activities...), just a little longer on the fronts which are about to cord due to camber wear.

I just ordered a pair of Federal ST-1s @ $112 a piece for the rear, fine by me because I like it when the rear is a bit squirrelly, but I'm wondering if you guys have input on fronts. Should I go with PS4S for better braking + grip + noise, or are there any decent alternatives?

Wet performance isn't a huge consideration, Indy 500s aren't great at it. I didn't like the V12s that I tried.

Wondering if any of you guys have made this compromise too

[rhyary]

The Ecsta PS91 has been the most cost effective tire for me. You can read about my tire experiments on my 2020 thread.

2020 HPDE season https://www.m3post.com/forums/showthread.php?t=1685308

[dparm]

Originally Posted by chocstraw

anyone else have a crippling tire addiction? I'm looking for low-cost alternatives as I don't really push my car too hard on the street, and have a set of Supercar 3Rs for the track.

I've been using Firestone Indy 500s for the street for a while now, I like Bridgestone sidewalls, but I'm barely 9 months on my rears and they're starting to cord (skidpad activities...), just a little longer on the fronts which are about to cord due to camber wear.

I just ordered a pair of Federal ST-1s @ $112 a piece for the rear, fine by me because I like it when the rear is a bit squirrelly, but I'm wondering if you guys have input on fronts. Should I go with PS4S for better braking + grip + noise, or are there any decent alternatives?

Wet performance isn't a huge consideration, Indy 500s aren't great at it. I didn't like the V12s that I tried.

Wondering if any of you guys have made this compromise too

Use matched tires. If anything, spending a few extra bucks on the street tires will be advantageous: quieter, longer life, better wet traction, etc. Tire hum gets old really fast, for example.

[Kelse92]

Update on the rear rotors, I emailed Girodisc yesterday and they responded!

Thanks for getting in touch and apologies for the delay it was a bit hectic here today. At any rate we have developed a rear for the e92 M3 but have not yet had a chance to get our hands on one to do a test fit with the prototype pair that we’ve manufactured. I hope to get my hands on a car here real soon to validate them and then we’ll get going on a production run. We will definitely have replacement rings available for the assemblies as well.

So something from them will be available Soon. No idea on price but if its within striking distance of the RB cost and not too overkill vs buying OEM I may just pickup a set.

[dparm]

The GiroDisc rings are usually about $700 regardless of application, which isn't bad.

[//steve\\]

Originally Posted by Kelse92

Update on the rear rotors, I emailed Girodisc yesterday and they responded!



So something from them will be available Soon. No idea on price but if its within striking distance of the RB cost and not too overkill vs buying OEM I may just pickup a set.

Great news! I'd be curious how much weight they save over OE too.

I don't even need them but I want a good option.

[Kelse92]

I've been overdue for rear rotors for awhile now. They haven't had any issues but they're starting to eat through rear pads at a higher rate so I need to change them...

[Richbot]

I have had a set of the Racing Brake rear rotors on my car for a long time. I'm not sure if they're still selling them or only selling them as part of a BBK now, but it is a direct-replacement option. Saved quite a bit of weight vs. the Turner/ECS rotors I had on it before.

[dparm]

The rotor rings generally don't save a ton of weight -- there's only so much iron you can remove and still have sufficient strength and mass for thermal dissipation. Much of the savings come from the hat. Every pound of unsprung weight counts, yes.


My car has a two-piece rear rotor from the factory, but it uses an iron hat for extra strength on the parking brake. GiroDisc's replacement uses an aluminum hat and saves EIGHT pounds per rotor.

Compare to the the OEM front which is iron rotor + aluminum hat, the GiroDisc savings is only 1.6 pounds.

[//steve\\]

Originally Posted by dparm

The rotor rings generally don't save a ton of weight -- there's only so much iron you can remove and still have sufficient strength and mass for thermal dissipation. Much of the savings come from the hat. Every pound of unsprung weight counts, yes.


My car has a two-piece rear rotor from the factory, but it uses an iron hat for extra strength on the parking brake. GiroDisc's replacement uses an aluminum hat and saves EIGHT pounds per rotor.

Compare to the the OEM front which is iron rotor + aluminum hat, the GiroDisc savings is only 1.6 pounds.

Right, it's the hats that really make all the difference. OE hats are iron on the E9x?

[SYT_Shadow]

Originally Posted by //steve\\

Right, it's the hats that really make all the difference. OE hats are iron on the E9x?

OE hats are alu on the E9X

[//steve\\]

Originally Posted by SYT_Shadow

OE hats are alu on the E9X

I don't have my facts quite straight yet. Haven't been around these long enough to be a know it all

I'd imagine that some kind of billet hat will still save a little over a cast style hat like stock.

[DRLane]

Originally Posted by //steve\\

I don't have my facts quite straight yet. Haven't been around these long enough to be a know it all

I'd imagine that some kind of billet hat will still save a little over a cast style hat like stock.

Curious, what are you solving for? Aren't you on AP BBK all around?

[Richbot]

The factory rotors are heavy because of how they're constructed not what they're made of

[dparm]

Originally Posted by Richbot

The factory rotors are heavy because of how they're constructed not what they're made of

Yeah, thery're not really a true two-piece floating rotor. It's more of a dual casting.

[ppatel14]

Originally Posted by Kelse92

I've been overdue for rear rotors for awhile now. They haven't had any issues but they're starting to eat through rear pads at a higher rate so I need to change them...

So I've been noticing this too on my rear axle. Everything is stock except SS lines and rear brass caliper guides. I added the rear caliper guides the same time as new PFC08 pads all around and the wear rate on the rear seems a lot more than my fronts. Mind you I was using OEM pads for the first couple track days and they were nearly even all the way around when I changed them out.

Thinking through this, I believe it has more to do with traction control then anything else. I run with Euro MDM most of the time on track unless its raining.

Also I'd like to add that FCP has added DTC-60 and 70 to their lineup. Anyone know how much material you need left before they accept returns?

[dparm]

MDM will work the rear brakes harder. It will drag the inside rear brake to keep the car tucked in. If you like having that safety net, then that's the price you will pay -- higher pad consumption.

Also, the "cornering brake control" (CBC) and EBD can do stuff on individual calipers as needed. Those two systems are not defeatable.

[rhyary]

Originally Posted by dparm

...Also, the "cornering brake control" (CBC) and EBD can do stuff on individual calipers as needed. Those two systems are not defeatable.

Are you sure about that?
I have been driving with DSC off for most of 2020 and I assumed it has not messing up with my brakes.

I can verify on my AiM data logs.

[dparm]

Originally Posted by rhyary

Are you sure about that?
I have been driving with DSC off for most of 2020 and I assumed it has not messing up with my brakes.

I can verify on my AiM data logs.

My understanding is that CBC and EBD are part of the ABS system. Happy to be proven wrong -- it's possible that the DSC computer tells the ABS computer to disengage those "enhancements" when DSC is turned off, but I've never seen anything in the BMW documentation indicating that's the case.

[tsk94]

Originally Posted by ppatel14

Also I'd like to add that FCP has added DTC-60 and 70 to their lineup. Anyone know how much material you need left before they accept returns?

Pretty sure they need to be worn down pretty close to the backing plate for them to accept them.

But either way that's an awesome way to keep consumable costs down while getting to run a true race pad.