October 2020 Fastrack - The Brake Rules...

[dhrmx5]

The allowance of any size rotor that fits in the wheel is too much. We have fitted 355/380mm rotors and 6 piston calipers inside 18" wheels with ease. There should be some sort of upper limit besides wheel size... The modern cars such as the FRS, 944, RX8 will be able to run massive brakes compared to the older cars...

There is. Four piston max calipers.

Four piston Calipers don't limit rotor diameter

 

[Peter Olivola]

The allowance of any size rotor that fits in the wheel is too much. We have fitted 355/380mm rotors and 6 piston calipers inside 18" wheels with ease. There should be some sort of upper limit besides wheel size... The modern cars such as the FRS, 944, RX8 will be able to run massive brakes compared to the older cars...

There is. Four piston max calipers.

Four piston Calipers don't limit rotor diameter

The wheels do and four piston calipers limit the swept area.

 

[Matt Blehm]

Most would be OK if B-spec was permanently moved in with SM and out of the production group. Maybe that’s letter worthy to make that change for all Majors/HST events?

Plus, that gives an opportunity for a HP/BS double dip would could generate a few thousand additional in entry fees.

Many in the BS clan down here are doing that. part of which was enabled to get BS out of small bore, but then the same guys run the same cars in HP with the same crowd...... :shrug:

 

[Tom Feller]

I meant to put this here, but put it in the survey thread instead.

I think that restricting the rotor size with the wheels is a mistake. It's exactly the kind of rule writing we want to avoid because it invites experimentation and expenditure...not only on brakes, but now on wheels.

And since you can't bitch without offering an alternative, here's an idea that would at least keep a lid on some of that:

EP = 13 inch max or stock diameter if larger

FP/HP = 11 inch max or stock diameter if larger

 

[GT6]

There are 13 inch wheels in EP.

Are we now allowing rotors to be attached to rims?
And consequently, the redesign of wheel centers?

 

[Tom Feller]

There are 13 inch wheels in EP.

Are we now allowing rotors to be attached to rims?
And consequently, the redesign of wheel centers?

No, in those cases, those folks are still going to seek the largest rotor that will fit the wheel (and probably look for wheels that make space for more brake hardware). But at least the guys with 18 inch wheels aren't.

 

[GT6]

What does, "fit the wheel" mean?

Is there some wording in the GCR that says where the rotor should live, or where it's attached?

 

[David Dewhurst]

Is there some wording in the GCR that says where the rotor should live, or where it's attached?

Reading the GCR glossary for the definition of Brake Rotor and Brake Rotor Hat provides a very clear definition as to where the rotor SHALL live.

 

[Tom Feller]

I think Anthony's concern is this. Could it be taken just a little more to the extreme? Seems like it.

 

[GT6]

David, thank you for pointing that out.

I agree that it seems clear from the glossary wording, to which component the rotor shall attach.
The definition of Hub in the glossary leaves a lot of room for where the rotor shall attach to it.

Still looking for definition on where the rotor should be located or how a wheel limits the rotor O.D.


Tom, a picture is worth a thousand words. Thanks,

 

[Matt Blehm]

Well, feel free to stick the rotor out of the wheel If you have room in the suspension and track width and spindle clearance, and can deal with the steering scrub.

 

[Tom Feller]

Well, feel free to stick the rotor out of the wheel If you have room in the suspension and track width and spindle clearance, and can deal with the steering scrub.

Yeah well, point is, there was no impetus to even consider it before. Now there is.

 

[Matt Blehm]

don't worry, before long they'll just lump Prod in with GT3/GTL and you can do what you want.....

 

[GT6]

Matt, why do you say that?

Is it because there are too few Prod cars, or because Prod is too close in prep and performance to GT3/GTL?

 

[Tom Feller]

don't worry, before long they'll just lump Prod in with GT3/GTL and you can do what you want.....

OK Matt.

Why is there a limit in ST but the Adhoc doesn't feel the need to have one in Prod? I think you're saying that we don't need a limit, right? If that is the case, then the limit should be removed from ST "because the wheel limits it naturally." I imagine there is some reason it's there. If not, take it out. If you don't want to take it out, then how can you advocate against a limit in Prod?

 

[Chris Schaafsma]

I think Anthony's concern is this. Could it be taken just a little more to the extreme? Seems like it.

Seems like it would be difficult to do this with a caliper mounted in the original location without making the bearing loading un-bear-able. I'm not worried about this idea one bit.

 

[GT6]

How do you determine that an alternate caliper is in the same location as the stock one?

My interpretation of that wording in the proposed rules was simply, general location. Aka, front, back, top, bottom.
Lateral location of the stock or alternate caliper seems to be free, but I could be wrong.

 

[Jonathan Spiegel]

I think Anthony's concern is this. Could it be taken just a little more to the extreme? Seems like it.

That's some serious scrub radius right there.

 

[Matt Blehm]

Matt, why do you say that?

Is it because there are too few Prod cars, or because Prod is too close in prep and performance to GT3/GTL?

Looking at car counts and the "creep" in philosophy such as this one, Prod and GT (and ST for that matter) are getting closer and closer together. before very long, the class consolidation philosophy and black helicopters will begin to see the classes as close enough to combine.

not saying I like it or that I support it, just that I see the proverbial wall and someone is headed that direction with a sharpie.

don't worry, before long they'll just lump Prod in with GT3/GTL and you can do what you want.....

OK Matt.

Why is there a limit in ST but the Adhoc doesn't feel the need to have one in Prod? I think you're saying that we don't need a limit, right? If that is the case, then the limit should be removed from ST "because the wheel limits it naturally." I imagine there is some reason it's there. If not, take it out. If you don't want to take it out, then how can you advocate against a limit in Prod?

ST limits rotors to 13" (I think that's the current max size but haven't read in a while), but they have a 17" wheel size limit in STL and 18" in STU.

consider that some of today's Prod cars already have large rotors (RX8 is 12.6" rotor), yet another EP car only has 13" wheels, it makes it really hard to mandate a common maximum brake size. allowing cars to fit whatever size rotor they want inside the allowed wheel seems like a relatively reasonable rule. moreso than saying 13" max rotor, and then everyone on 13 and 15" wheels would want to run a 17" wheel to clear the now allowed 13" brakes... so if you change one rule- single max size brakes for everyone- then competitors are going to want to change another- single max size wheels for everyone- to take advantage of those brakes. Where do you draw the line?

If you draw the line at keeping the current wheel sizes, then allowing competitors to fit whatever brakes they have inside those wheels seems reasonable to me. My $0.02, YMMV, opinions and a-holes, all that jazz. If you disagree, we can still be friends.

 

[Protech Racing]

Run really large rotors? Just like running the largest wheels. Takes more power to turn them .
Run the smallest rotating parts that will do the job .
Al these guys are gunna put on big brakes and 40# and go slower. Stops gooder tho.
Gooder.