Girodisc Versus OEM rotors for track use

[USSEnterprise]

I am currently using Girodisc 2 piece rotors front and rear on my track F80. I have 29 sessions on them and they perform great, wearing very well, don't squeal and seem to run cool. I am VERY happy with them and hope to get much more life out of them.

However, FCP now carries OEM rotors and I am wondering about switching to them for my next set due to the long term cost advantages. I have never had OEM rotors since my car was originally CCB and I went straight to Girodisc when I did the steel rotor conversion.

So, I'd like to hear from folks with OEM BMW steel rotors that track their cars frequently - can you tell me how they performed and how many sessions/days/track miles you got out of them?

[SYT_Shadow]

There is a BIG difference between quality aftermarket rotors (in this case, Girodisc) and OEM rotors

We briefly used OEM M2 rotors on a CCB F82 GTS and it was a mess. If you are hard on the brakes you go through front rotors non stop. Switching to Girodisc made a big difference.

Obviously not everyone uses their brakes as a device to be faster, so for some people the OEM brakes work just fine.

If you look at the cooling vanes in a Girodisc rotor and compare it to an OEM rotor, the difference is huge. And track rotors are not drilled either.

[sc_tr0jan_m3]

It's hard to compare to free warranties via FCP. I've gone through multiple pads, oil changes, and brake fluid with zero issues. I still run a stock rear setup in my e46 m3 and being able to warranty those pieces with FCP is a big reason why I haven't upgraded to a rear BBK.

[dvq]

Originally Posted by sc_tr0jan_m3

It's hard to compare to free warranties via FCP. I've gone through multiple pads, oil changes, and brake fluid with zero issues. I still run a stock rear setup in my e46 m3 and being able to warranty those pieces with FCP is a big reason why I haven't upgraded to a rear BBK.

Some ducting and OEM iron rotors from FCP w/ lifetime warranty and having a street rotor set as well as a track rotor set while bringing streets as backups is probably by far the best cost sensitive approach.

[NYG]

Originally Posted by SYT_Shadow

There is a BIG difference between quality aftermarket rotors (in this case, Girodisc) and OEM rotors

We briefly used OEM M2 rotors on a CCB F82 GTS and it was a mess. If you are hard on the brakes you go through front rotors non stop. Switching to Girodisc made a big difference.

Obviously not everyone uses their brakes as a device to be faster, so for some people the OEM brakes work just fine.

If you look at the cooling vanes in a Girodisc rotor and compare it to an OEM rotor, the difference is huge. And track rotors are not drilled either.

This.

I used FCP for the stock rotors a few times. They're garbage IMO.

Also, remember that you'll be paying a lot of money to ship those back.

[hatepotholez]

I was thinking the same thing, swap in OE discs every 3 track events or get the giro disc and swap every 6 track events or every year. But sometimes I wonder how long FCPEURO will have their lifetime warranty?

[dvq]

Originally Posted by hatepotholez

I was thinking the same thing, swap in OE discs every 3 track events or get the giro disc and swap every 6 track events or every year. But sometimes I wonder how long FCPEURO will have their lifetime warranty?

Until they don't or until they go out of business.

[SYT_Shadow]

I find people returning track consumables or oil are abusing the system and may wind up bankrupting them... and kill the goose with the golden eggs

[NYG]

Originally Posted by SYT_Shadow

I find people returning track consumables or oil are abusing the system and may wind up bankrupting them... and kill the goose with the golden eggs

For a second I thought you were talking about the current state of politics in the US.

[dvq]

Originally Posted by SYT_Shadow

I find people returning track consumables or oil are abusing the system and may wind up bankrupting them... and kill the goose with the golden eggs

I don't personally do it, but they advertise it -- they even have an entire IG account dedicated to returned items and consumables.

https://www.instagram.com/fcpeurolrg/

[x.shell]

Originally Posted by SYT_Shadow

I find people returning track consumables or oil are abusing the system and may wind up bankrupting them... and kill the goose with the golden eggs

Originally Posted by dvq

I don't personally do it, but they advertise it -- they even have an entire IG account dedicated to returned items and consumables.

https://www.instagram.com/fcpeurolrg/

At first, I thought the same thing in terms of "gaming" the system. But as dvq said, FCP is really pushing the life-time-replacement deal in their own marketing. It's not a even a wink/nod; it's straight up DTF in the open. So bang away.

Any smart business knows they have to weight the costs versus return on investment. And I think FCP might have a good strategy here. The deal probably lures customers that were once loyal ECS customers -- which amounts to more sales. But in reality, the likely situation is that more customers buy products based on the life-time-replacement warranty, while only a small number of them actually use it.

Lets take oil changes for example. Sure I could ship all my used oil and filter back into FCP to get a replacement, but I'm not gonna leave my car drained until I get a new kit shipped back to me. So I would need another set on hand in the mean time; which means I would've bought 2 kits from FCP to begin with. But the cost/inconvenience of shipping back 7 quarts of used oil back really makes me hesitant on taking advantage of the deal. It kinda reminds me of those infomericals where you get a "2ND PRODUCT FREE! ***Just pay shipping and handling***"; where shipping/handling costs almost as much as the product itself.

Taking all that into consideration... sure, you may net out with saving money (if you don't consider time as money). But unless you're really going through rotors and oil hard on the track, the deal probably isn't worth it.

[F80Speed77]

I think FCP is doing fine considering they are running an AMG GT4 car in IMSA Pilot Challenge lol.

Running the OEM M2C rotors on my Time Attack F80. I only have 2 events on them so far but they seem fine. I don't drive 10/10ths for 20min at a time though. My rotors weren't glowing like everyone elses when racing in the dark at Gingerman so I think they are adequate haha.

[SYT_Shadow]

Originally Posted by F80Speed77

I think FCP is doing fine considering they are running an AMG GT4 car in IMSA Pilot Challenge lol.

Running the OEM M2C rotors on my Time Attack F80. I only have 2 events on them so far but they seem fine. I don't drive 10/10ths for 20min at a time though. My rotors weren't glowing like everyone elses when racing in the dark at Gingerman so I think they are adequate haha.

Very different use case vs someone hammering the car for 30 minute sessions, 3-4 times per day, during a 3 day weekend

[Driver407]

Pretty sure FCP has you buy the replacement/new oil. Then once you have installed the new oil, you send back the used oil you previously bought with them and they refund you. You wouldnt have to have your car drained while you wait.

I just bought and installed my first liqui-moly kit from them last week and this was my understanding when I read the paperwork in the box.

[sc_tr0jan_m3]

Originally Posted by irokdayellup

Pretty sure FCP has you buy the replacement/new oil. Then once you have installed the new oil, you send back the used oil you previously bought with them and they refund you. You wouldnt have to have your car drained while you wait.

I just bought and installed my first liqui-moly kit from them last week and this was my understanding when I read the paperwork in the box.

this is 100% correct. your car isn't left on the stands while you wait for oil.

[FormulaMMM]

Went from OE cross drilled to Girodisc on another platform. Would never take cross drilled over slotted for track use. And as shadow referenced the curved vane design of the Girodisc. They're purpose built, proven in many track circles.

Also don't care for interpreting cross drilled as they crack and wear from track use. Here's where I called it quits on a cross drilled set pre-Girodisc. Maybe some life left, maybe not, maybe I get half way through the next track day and one of these suckers opens up. Just easier to read slotted discs imo.

[RSXDC5]

It's also worth pointing out:

-The iron blend used in the Girodisc rotors is superior to the oem rotors.

-The replacement cost of the Girodisc rotors is not $1300 per axle, it's around $900 per axle as you only need the rotor ring itself.

[sly1types]

What are your thoughts on these stoptech aero rotors for stop calipers vs the Girodisc ones?

https://www.bimmerworld.com/StopTech...-M3-M4-M2.html

Are the Girodisc worth the $300?

[m4forum]

I hear a lot about aftermarket rotors are better because they have higher thermal capacity. In order to have more thermal capacity it is required to have higher mass. One of the advantages some companies market is the fact their solutions are lighter than stock rotors so less mass. Then what is the advantage of an aftermarket rotor -> heat dissipation. Despite the face it can actually have less mass (thermal capacity) it can dissipate the heat faster meaning after a hard breaking point the rotor can lose temperature faster and be actually at lower temperature compared to a stock rotor for the next braking point. It can be achieved by increasing the number of vanes and its design. This is the theory. I would like to see some date but didnt have a chance to compare them.

[Montaver]

Originally Posted by m4forum

I hear a lot about aftermarket rotors are better because they have higher thermal capacity. In order to have more thermal capacity it is required to have higher mass. One of the advantages some companies market is the fact their solutions are lighter than stock rotors so less mass. Then what is the advantage of an aftermarket rotor -> heat dissipation. Despite the face it can actually have less mass (thermal capacity) it can dissipate the heat faster meaning after a hard breaking point the rotor can lose temperature faster and be actually at lower temperature compared to a stock rotor for the next braking point. It can be achieved by increasing the number of vanes and its design. This is the theory. I would like to see some date but didnt have a chance to compare them.

I believe aftermarket options like Girodiscs, Essex etc. save weight in the hat as well not just the rotor. I have Girodiscs on my GT4 and they are very sturdy indeed. Especially when compared to the stock rotors on my M2C which did one 3 day weekend and were already cracking from the holes to the point I binned them before selling the car shortly after.

[m4forum]

The holes on stock rotors helps with cooling but has a side effect on longevity. I would like to try Girodisc and test their performance. If there is a change to improve cooling on rotors do it specially with aftermarket rotors which will benefit them a lot and reduce overall brake temperature. I have done some testing on brake cooling and realized most solutions for M4 requires a 90 degree bent which kills air speed by 67% meaning air getting into the rotors is extremely reduced so the benefit of cooling is dramatically minimized. In couple weeks I am going to try a cooling solution for the rear which I am very helpful can have a solid impact in reducing brake temperature. I installed fan on each side which will pull 160CFM air on each rotor at any speed.

[USSEnterprise]

Originally Posted by m4forum

The holes on stock rotors helps with cooling but has a side effect on longevity. I would like to try Girodisc and test their performance. If there is a change to improve cooling on rotors do it specially with aftermarket rotors which will benefit them a lot and reduce overall brake temperature. I have done some testing on brake cooling and realized most solutions for M4 requires a 90 degree bent which kills air speed by 67% meaning air getting into the rotors is extremely reduced so the benefit of cooling is dramatically minimized. In couple weeks I am going to try a cooling solution for the rear which I am very helpful can have a solid impact in reducing brake temperature. I installed fan on each side which will pull 160CFM air on each rotor at any speed.

There is a lot to brake thermal dynamics than just blowing air on the rotor. Cooling a rotor too fast will also result in the metal cracking/deforming.

It’s pretty complicated science. I admire your home ingenuity, but I’m sorry to tell you that if sticking a fan on the side of the rotor was the ticket, the big manufacturers with billions of dollars in R&D in their racing teams would have done it 30 years ago.