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315 R6s on all four corners

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ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
neema said:
No rubbing in the back? Looks good.

Very little. The fender roll should take care of it no issue. Gonna depend on your ride height, shock travel/bumpstop, and spring rate though.
 
ArizonaBOSS said:
Very little. The fender roll should take care of it no issue. Gonna depend on your ride height, shock travel/bumpstop, and spring rate though.
The Hoosiers seem to be on the wider side compared to the Continentals and part of it is the rim proetector I am guessing. If I wasn't changing cars next year I would go with a aet of coilovers and roll the femders. As it stands I will probably just run tge 295s up front but on the bigger 11" Forgestar rims should get a wider contact patch than the 9.5s.

Do the R7s seem to be every bit as good as the R6s? I have a 295 R6 here to test fit and am assuming the 295 R7 will be the same width?
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
Cloud 9:

What new car do you have planned for the 2016 season? Will you do another build, or do you have a turn key in mind?

Good luck this year,
Dave
302 Hi Pro
 
302 Hi Pro said:
Cloud 9:

What new car do you have planned for the 2016 season? Will you do another build, or do you have a turn key in mind?

Good luck this year,
Dave
302 Hi Pro
GT350. Hopefully my dealer gets an R which should limit the build to a roll bar, race seats and tow hooks....although even with the base version that list doesn't change. ...well at least until aftrr the first TT event ::)
 
ArizonaBOSS said:
This setup has over an inch more tire width vs. the 305 pirellis on a 10" wide wheel, not to mention a wider track width all-around.

11024644_10100874470221664_6986303620325321442_n.jpg

Interestingly enough, (not sure what kind of pirellis you were using), the P315/30ZR18 DOT Hoosier R7 tread width is 11.8" and the 305/680/18 Pirelli PZero competition slick tread width is also 11.8" (albeit a larger sidewall). But the 315/680/18 Pzero's have a .2" smaller tread width than the pzero 305's and a .6" bigger section width!.....lol.....what???

How are your sidewalls holding up? Are they bulging a bit on those rims? Keep an eye on the the tire edges, when i ran the DOT hoosiers (previous model R6), they had soft sidewalls and resulted in this (below). I also was running them on a .5" smaller than optimum rim at the time. The hoosiers (talking from R6 use here, may be different now) require a lot more psi than one might think. I think Tim at Hoosier said close to 40psi hot for our cars!

hoosier1.jpg

hoosier2.jpg

hoosier2.jpg
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
cloud9 said:
Do the R7s seem to be every bit as good as the R6s? I have a 295 R6 here to test fit and am assuming the 295 R7 will be the same width?
Too early to say for sure. Not sure if I have the optimum tire pressures but they have a ton of grip (only two runs, no pre-heat cycle). The turn-In response is better than any tire I've run so far
 
ArizonaBOSS said:
Too early to say for sure. Not sure if I have the optimum tire pressures but they have a ton of grip (only two runs, no pre-heat cycle). The turn-In response is better than any tire I've run so far
I'm not sure where you're targeting pressures, but I found my best results with fronts at 40-43 HOT and rears at 38-40 HOT.
 
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Cloud9, What is the backspacing of the 18 x 11 Forgestar wheel? I know Vorshlag does not publish the offset, but did you measure the backspace before you mounted the tires? I ask because I thought these were supposed to fit without spacers, even with 315 tires as Vorshlag ran a 18 x 11 with the same 315 Hoosier before the flared fenders. Also, it seems in the photos you have a pretty big camber difference between driver and passenger side. Are you maxed out camber wise? I was thinking of these wheels with the 305 NT01's, but maybe the 10.5" Enkei would be the better fit.
 
ArizonaBOSS said:
Darren: the 315 R7 on 10.5 is bottom left, 305 Pirelli DH on 10 is lower right.

yO1WwxU.jpg

Yeah, because you were running lower sidewall pirellis I guess. That's a big difference.

But here's what their websites say. You know, part of me wonders if websites are accurate sometimes.

Hooiser 315 treadwidth, 11.8"
hoosier-size.png

EDIT: Looks like I pulled the street version above. Couldn't find 315's on the radial slicks list, but here it is. Prolly around the same 11.8"ish.
Interesting the 320's and 305's have same treadwidth (different sidewalls though)
hooiser2-sizes.png


Pirelli 305 treadwidth, 11.8"
pirelli.png
 
cp85gt said:
Cloud9, What is the backspacing of the 18 x 11 Forgestar wheel? I know Vorshlag does not publish the offset, but did you measure the backspace before you mounted the tires? I ask because I thought these were supposed to fit without spacers, even with 315 tires as Vorshlag ran a 18 x 11 with the same 315 Hoosier before the flared fenders. Also, it seems in the photos you have a pretty big camber difference between driver and passenger side. Are you maxed out camber wise? I was thinking of these wheels with the 305 NT01's, but maybe the 10.5" Enkei would be the better fit.
I didn't measure it so am not sure. John (LS110) and I have both been going through this fitment process together. Both of us are gaining camber by hogging the lower strut hole. If you true up the strut to spindle mounting to the factory holes you can make them fit without spacers but John could only get -2.0* of camber with MM caster/camber plates. My driver and passenger camber is at -2.7* The driver side photos are with the tire sitting on 5" of boards. I think the difference you are seeing is camera angle as they are the same (at least last time it was on the rack). I can get at least -3.0* with the way they are tipped in at the strut to spindle but that's too much IMO. I'm still concerned they will rub the fenders without rolling them. I laid the Forgestar 18 x 11 with 315 R6 next to an Enkei 18 x 10.5 with 315 R6 and I am going to guess it's at least 1/2" wider on the Forgestar. That's what has me leaning toward just running the same size tires I was running last year on the Forgestar's but still achieving a wider actual tread width. I think you'd be fine with an NT01 in a 305 as I don't think they run as wide as the Hoosiers. I wish Hoosier made an R6 (R7) in a 305.......
 
cp85gt said:
Cloud9, What is the backspacing of the 18 x 11 Forgestar wheel? I know Vorshlag does not publish the offset, but did you measure the backspace before you mounted the tires? I ask because I thought these were supposed to fit without spacers, even with 315 tires as Vorshlag ran a 18 x 11 with the same 315 Hoosier before the flared fenders. Also, it seems in the photos you have a pretty big camber difference between driver and passenger side. Are you maxed out camber wise? I was thinking of these wheels with the 305 NT01's, but maybe the 10.5" Enkei would be the better fit.

I have run 305 NT01's on my Vorshlag 18X11 Forgestars with no rubbing. You will need lots of camber in the front. I run 2.7 degrees.
 
110
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I think the Vorshlag car runs around -3.5 so the extra -1 degree of negative camber has apparently helped them get the 315 Hoosier under the stock fender on the 11" wide wheel. The Vorshlag camber plates seem to allow a bit more negative camber than the Maximum Motorsports plates do. I do have a set of AST 4150's with the Vorshlag camber plates already on the car. 06Mach1, how did you like the NT01's 305 square on the 11" wheels? I wonder if the extra rim width over the Enkei wheel would extend the life of the NT01 tire to negate the lack of ability for wheel rotation.
 
cp85gt said:
06Mach1, how did you like the NT01's 305 square on the 11" wheels? I wonder if the extra rim width over the Enkei wheel would extend the life of the NT01 tire to negate the lack of ability for wheel rotation.

I did not use the Nittos very long as they did not perform well for me. They wore fine, just did not seem to be very sticky. Tried all different pressures with no better results. Might just be my driving style too. I switched to P-zero take off slicks in the same basic size and love them.
 
Rick asked me to check in here, I ran 315 square all last year in hoosier a6's and bfg r1-s on 10.5 wide rims no-real issues except with wide spacers on front and fender contact with full turn input. SCCA t-1 doesn't allow mod to fender (other then folding inside of lip) so that was an issue but if you can get a little "flair" with the lip roll should be good to go!
 
NFSBOSS said:
Thanks John. John is using the CorteX/Jongbloed 18x10.5" wheels.

http://www.cortexracing.com/shop/jongbloed_700/
When I laid an 18x10.5 Enkei next to an 11" Forgestar, both with R6 325s, the Forgestar was noticably wider. I wonder what the actual tread width difference is that you get from a 315 on a 10.5 versus a 295 on an 11.
 
ilesjohn said:
Rick asked me to check in here, I ran 315 square all last year in hoosier a6's and bfg r1-s on 10.5 wide rims no-real issues except with wide spacers on front and fender contact with full turn input. SCCA t-1 doesn't allow mod to fender (other then folding inside of lip) so that was an issue but if you can get a little "flair" with the lip roll should be good to go!
Thanks John. Are you using a racing coilover or standard size OEM strut? There's a pretty big difference in spring diameter with the racing coilovers.
 
cloud9 said:
Thanks John. Are you using a racing coilover or standard size OEM strut? There's a pretty big difference in spring diameter with the racing coilovers.
Coilovers with cortex offset strut housing, I think 11-inch wide wheels would be better for a 315 setup
 

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