The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

15" GT500 brakes/18" wheels

PeteInCT

#LS-378 - So many Porsche's, so little time....
Moderator
2,848
14
Connecticut
Having issues with stock front calipers ? If those are the same as the brakes on the 302S then you may find that you need to change more than just the calipers (master cyl, ABS, etc.) like Roketman did. Have you thought of upgrading pads/rotors?
 

PeteInCT

#LS-378 - So many Porsche's, so little time....
Moderator
2,848
14
Connecticut
Does stop-tech make a 6 caliper for us? I used them in the past and was very happy with them.
 
It was suggested to me that the 6 piston GT 500 brakes will only provide a bit more cooling with the larger rotor and not necessarily more stopping power. The 302R/S BBS wheels should clear those calipers. Call Rehagan Racing and talk with them to verify.
 
I don't know if this will help you but I have the wheels below. I measured about 6-7mm clearance with the Boss's Brembo's. Dosn't look as close as the original rims. They weigh in at 29lb though.

from Trublue racing >M-1007-DC1895 05-12 SVT 18"X9.5" WHEEL $175.99 - delivered
 
1,255
2
GA
5 DOT 0 said:
It was suggested to me that the 6 piston GT 500 brakes will only provide a bit more cooling with the larger rotor and not necessarily more stopping power. The 302R/S BBS wheels should clear those calipers. Call Rehagan Racing and talk with them to verify.

Some technical papers I have read on the subject have said that larger brakes really just provide more surface area for better cooling. Your tires are really what stops your car.
 
That has been my understanding too (once you have a high quality brake system - I have never driven a car that I could not lock the brakes if I really wanted to so lack of total power isn't really an issue), but there are other factors. Feel is a huge part of it imo, BMW M brakes for example are like an on/off switch, so even though you can in theory brake brake just as well as with a brake with more feel, they are not confidence inspiring. This is one of the big benefits of quality setup, as the feel also will be more consistent through as they get hotter (and they should get hot slower due to better cooling) so you know what you will get each time and have confidence. My Evo the brakes would fade suddenly, so after several hard deceleration zones I would start to lose confidence and brake earlier. A really bad brake system (the drums on my dirt bike is an example) also will be hard to keep from locking on hard braking sue to the non-progressive nature (like BMW M but worse), and you don't really want ABS kicking in all the time even if you have it. Also the ABS controller can affect distances, many systems kick on too early and so actually extend braking distances the same as bad TC. For one hot lap, ours are probably as good as the GT500 but over a session, the total braking will likely be better with bigger brakes assuming that they are of equal quality and you are running the car hard enough that brakes even become a factor.

Sort of like how a seat won't make your car faster but having one that plants your butt well will make you faster, especially over time as there is less fatigue from straining to stay in place.

Now do the GT500 brakes do any of that? Somebody would need to test them.
 

Sesshomurai

You might need .25" wheel spacers to fit them. 302r wheels require it on brembo s197's.
 
Anyone ever verify 18" BBS wheels from FRPP fit? or any other 18"

I have 13 GT500 brakes on my boss and need to pick up a set of track wheels.

The stock brembos with carbotech XP12s performed well, but were running about 600F around AMP, I would like a little more cushion, as I could feel them fade a little if I ran it hard for several laps. This was still on a stock tire.
 
Anyone ever verify 18" BBS wheels from FRPP fit? or any other 18"

I have 13 GT500 brakes on my boss and need to pick up a set of track wheels.

The stock brembos with carbotech XP12s performed well, but were running about 600F around AMP, I would like a little more cushion, as I could feel them fade a little if I ran it hard for several laps. This was still on a stock tire.
Read post #5.
 

ArizonaBOSS

Because racecar.
Moderator
8,545
2,376
Arizona, USA
StopTech makes and ST60 kit that will clear 18" wheels, but IMO it's not any more effective than the 4-piston setups w/ good pads, and the ST60 pads are another $150/set over the Brembo-style 4-piston pads in the same compounds.
 

Sesshomurai

My own inquiry into this (looking at the Brembo GT-R package) turned up this response from one seller who spoke with Brembo. I also have the Brembo brake system CAD drawing with measurements if you want me to post it.

I was asking if the kit would fit the 18" 302s wheel Summit sells.

As this uses a 380mm disc, most likely, this kit would require a wheel 4"
larger than the disc, so a 19" wheel would be used. However, some wheels
have much more clearance than others and an 18" wheel may clear, but it will
be tight if it does.

I've attached the wheel clearance diagram for this kit. You may be able to
have Summit check it against their wheel to verify it clears.

Our kit needs 220.7 x 2 = 441.4mm in the barrel. That's 17 3/8" overall, so
not likely to find an 18" wheel with that much clearance inside the barrel.
The GT500 uses a 19 to clear it's larger Brembo brakes and the Boss 302 has
an optional 19" wheel available, so running a 19 would allow the use of our
kit and still be in the character of the car.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
Steve, I have been working with Team Dynamics on an 18x10 wheel for the Mustangs. My requirements were: 1) ford hub diameter, 2) had to use stock lug nuts, 3) the perfect offset for the S197, 4) must be strong enough for street and track duty, 5) must clear the Stoptech 15" 6-pot BBK (which take up the same space as the '13 GT500), 6) reasonably priced. Well, after some time, we have worked out the details and they are being manufactured now. They anticipate having them in the US and ready to ship out in March. These are based on their Pro Race 1.3 line. They will be offered in black and hi def silver. No official weight yet, but it should be around 24.5lbs. Not the lightest, but again, they are strong enough for torn up city streets. Pricing will be set at $310 each. I will list them on the site once i have confirmation of their arrival.
 

Sesshomurai

NFSBOSS said:
Darren, I'm not familiar with Brembos GR-R calipers but the 302S and 302R BBS wheels work with the race calipers which are larger than the calipers on our cars. That's what they were designed for and there are no fitment issues although you may need a small spacer for the front. The best thing to do is call one of the race shops like Rehagan and talk to them.

I have been (rogue engineering). Here is the kit I was looking at, but the quote I provided above is what they told me, that the taller 15" rotor poses a potential problem for 18" wheels. I'm sure, like the calipers on the 302s/R the calipers will clear the wheel backspacing, its maybe more a matter of diameter fitment inside the barrel. I'm still feeling this issue out. I don't think the 302s/r run 15" rotors though.... :-\

http://www.rogueengineering.com/bmw/B.html
http://www.horsepowerfreaks.com/partdetails/Brembo/Brakes/Big_Brake_Kits/GT-R/16408
http://www.beastpower.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=BMI&Category_Code=brembogtr

PS. Sorry Steve to steer off your topic slightly...
 

Sesshomurai

NFSBOSS said:
Rehagan is recommending those brakes?

No. I didn't talk to rehagen yet about brakes.

I found those brakes and was inquiring with the seller. I was curious if I could fit the bigger 6 piston GT-R brakes. I don't think rehagen runs 6 piston (or the GT-R) brakes at all from what I've seen. But will double check.

Here's a video for the brembo GT-R brakes btw. Again, sorries for the semi-hijack!

[youtube]http://www.youtube.com/watch?v=BJXkR21Zd5I[/youtube]
 

steveespo

Lord knows I'm a Voodoo Child
Moderator
3,752
1,223
Exp. Type
Time Attack
Exp. Level
10-20 Years
NY Metro
pufferfish said:
Steve, I have been working with Team Dynamics on an 18x10 wheel for the Mustangs. My requirements were: 1) ford hub diameter, 2) had to use stock lug nuts, 3) the perfect offset for the S197, 4) must be strong enough for street and track duty, 5) must clear the Stoptech 15" 6-pot BBK (which take up the same space as the '13 GT500), 6) reasonably priced. Well, after some time, we have worked out the details and they are being manufactured now. They anticipate having them in the US and ready to ship out in March. These are based on their Pro Race 1.3 line. They will be offered in black and hi def silver. No official weight yet, but it should be around 24.5lbs. Not the lightest, but again, they are strong enough for torn up city streets. Pricing will be set at $310 each. I will list them on the site once i have confirmation of their arrival.

I am interested but would prefer 9" wheel up front. I have a stock of 265 section Pirelli Grand am slicks that I would like to use. I guess I can look for 285s. Will the wheels work front and back? I run 305s out back and the just are on the fender edge, hopefully the offset will keep the tire in.
Post a picture if you can. Thanks
Steve
 

pufferfish

Supporting Vendor
1,094
66
Maryland
i only have the 10's on order, but 9" can be special ordered. no price adder(might actually be less since they are smaller), but could take up to 8 weeks to deliver. what wheels do you have those 305's on now? if you know the offset and rim width, i can calculate exactly where they will sit relative to where they are now.
 

TMO Supporting Vendors

Top