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!

315/30r19 square on 19x11 EC-7? (Base GT)

2017 base Mustang GT.
The car is nearly a dedicated Track/Autocross car. I drive to events. I already have the 19x11 ET52 EC-7 wheels.
I am currently running Bridgestone RE-71R tires at 305/30r19 square with no issues. I have Ford Perf Pack shocks/struts, GT350R springs. Vorshlag C/C plates, 25mm spacers up front, ARP wheel studs. Will be upgrading soon to GT350 6-piston Brembo brakes. My camber is currently -2.5 front / -1.4 rear. The Apex fitment guide indicates I can fit 315 tires up front with at least -3.0 camber. I am specifically looking at Falken RT660 tires at 315/30r19. That tire is .3” taller and the section width .5” wider than my current tire. I just want to confirm that these tires will functionally fit with the required camber. A 30mm spacer would be fine if that’s all I might need.

Talked to a couple guys with CAMT Stangs running 11” wheels with 315 Rival S square. One moved up from 305s and thinks he’s gained about .3 seconds on 50 second autox run. He’s experienced and fast. The other guy was running 285s previously so not much relevant intel there on time gains.

Apex says they will fit with more neg camber but recommended 11.5” wheels as optimal. Tire rack says 11” wheel is just fine. That’s it’s measured rim width.

So, two questions:

First, fitment. Will they really fit up front? Is anyone running similarly? Don’t want to take too big a chance not knowing. Not the end of the world, but a huge hassle to dismount, sell tires and wait for another set of 305s.

Also, time gains. Is it worth it? What to expect? I’d do it for 0.3 seconds - often the difference in winning CAMC or not - but probably not for less. And on the track, is this too much pinch, either with regard to performance or safety?

When it warms up today, I’ll pull the car out and check the current clearances. Bit what to look for in terms of room for compression?

Any knowledge on this would be appreciated! Thx.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
5,549
4,081
Exp. Type
W2W Racing
Exp. Level
20+ Years
Blair, Nebraska
Pretty sure you will be fine , but since you have Vorshlag Plates I would think you could get a bit more negative camber out of them just to be sure. DaveW or Dave_W might jump but pretty sure you will be okay as I have a friend running 325/30/19 Goodyear F1 Supercar 3s. Hang in there as DaveW not only runs in CAM, he also sells and mounts some tires with his race Oriented company and he likely has seen the usage already.
 
I recommended the 11.5" wheel just due to how wide that specific 315 tire is. I'd rather see you run their 305/30-19 as it's a better use of the setup, but if you really need to run the 315 then you can. It just won't be optimized on there.
 
I recommended the 11.5" wheel just due to how wide that specific 315 tire is. I'd rather see you run their 305/30-19 as it's a better use of the setup, but if you really need to run the 315 then you can. It just won't be optimized on there.
Thank you very much. I think sub-optimal would be ok, if, like I said above, it would be enough of an improvement. Just tough to know. I’d think about new wheels next year.
 
Still trying to decide on this. I’ve got 7mm between tire and strut. If Falken’s measurements are correct, the new tire would clear by .65mm, which I would think is too close. So, a lightly thicker spacer, maybe 27mm. But...

I’ve already got some poke. About a 1/4 inch or slightly more, which surprised me. I’m not sure how it isn’t hitting the top of the fender lip when the suspension is compressed. There no evidence on the lip or the tires to indicate it’s hitting. Because the tires are just 26.2” diameter there’s some room there for vertical travel - Maybe with the stiff springs and struts it just doesn’t compress enough? It doesn’t seem like another half degree of neg camber will make it tuck inside, especially when the new tire will be slightly taller.

Here are the pics, showing strut clearance, poke, and some in action with suspension compressed under braking and a little turning.

934A933E-9CC7-4EF6-A5B2-6FE8930AA546.jpeg

F27F644B-C040-4899-9590-D0EBE550D474.jpeg

649983BE-ACDD-476B-A47A-ED9386587D68.png

97059D5A-34ED-4082-9B4D-46CB1360CF78.png

987E7C55-56F9-4383-AFA6-BA96C33FFBE4.png
 

Bill Pemberton

0ld Ford Automotive Racing Terror
5,549
4,081
Exp. Type
W2W Racing
Exp. Level
20+ Years
Blair, Nebraska
You comment at the bottom, " I may be slow, but I sure ain't fast , " needs to be changed to , " My tires be fat and that's where it's at." Or, "My wheel wells are full and that's no Bull. " Seriously, nice shots and your GT looks quite intimidating and I have to imagine you are quite a bit quicker than your modest assessment"?!
 
Haha. Thanks. Maybe I’m sandbagging just a bit, but it was closer to true a year ago.
You comment at the bottom, " I may be slow, but I sure ain't fast , " needs to be changed to , " My tires be fat and that's where it's at." Or, "My wheel wells are full and that's no Bull. " Seriously, nice shots and your GT looks quite intimidating and I have to imagine you are quite a bit quicker than your modest assessment"?!
 
Well, I got some more opinions on this thru messages with folks on this site and from elsewhere, and I’m going to try it. Gonna be a couple months before the big Falkens ship, but I’ll report back, good or bad. Thanks all for the responses!
 
The 315/30-19 Falkens have arrived. They are MASSIVE - They look like 325s.

Width at the widest point, unmounted and upright, is 13 7/16” (13.31”). Falken publishes “overall width” as 12.8”. I believe that usually means MOUNTED (on 11-inch “measuring rim”), but lifted, so not bearing weight.

Can anyone please shed some light on this? On 11” wheels they’ll pinch in some probably, but not a half inch, right? I didn’t expect them to be exactly 12.8“, but close enough to try front fitment. Am I missing something here?

Thanks!
 

Ludachris

Chris
Staff member
Moderator
1,210
1,240
Exp. Type
HPDE
Exp. Level
5-10 Years
Newcastle, CA
Pretty sure you will be fine , but since you have Vorshlag Plates I would think you could get a bit more negative camber out of them just to be sure. DaveW or Dave_W might jump but pretty sure you will be okay as I have a friend running 325/30/19 Goodyear F1 Supercar 3s. Hang in there as DaveW not only runs in CAM, he also sells and mounts some tires with his race Oriented company and he likely has seen the usage already.
Might be a little late for this discussion, but America's Tire has a deal on the Goodyear F1 Supercars right now.
 
Update: I installed the Falken 315’s on the front of the car this morning. Have also gone from -2.6° front camber to -3.1°. The added camber leaves about the same amount of poke as the 305’s, but these tires are also about a half inch taller.

Surprisingly, they clear the struts with the existing 25mm spacers. I had 28mm spacers on hand, but it looks like I won’t need them - There is still a good 3-4mm clearance.

I tried a hard pull on a circled exit ramp and compressed the left front suspension to maybe 90%, and also slammed full-on the brakes at 65mph, and there is no evidence of tires rubbing the fender lip. They do rub in one spot (at full lock) where the splash guard plastic is slightly raised, but the 305’s had already worn a small hole through the plastic there, and those tires never showed any ill effects through their entire life.

I‘m thinking I’ll put some painters tape on the fender lips to be sure the tires aren’t rubbing there. And also get the car lifted and inspect all around the inside wheel wells.

Im thinking if nothing looks too bad, I’ll test them at an AutoX on the 14th. Anything else I should do to check clearance?

Thanks for all the help on this!
 
First of all I love your car also since today is 19th of August did you actually AutoX your 315 setup ? Did it make an improvement is it rubbing ?
Hey, thanks. I’d forgotten to report back on that - I did run last weekend. It went great! I’ve not lifted the car to inspect around the tires, but I’m pretty sure it’s as I wrote above, only some rubbing on the splash guard near full lock. Easily avoided by being careful with the wheel, but I don’t think it‘s doing harm regardless.

I had my best finish ever. Only Tim Aro, a multiple National Champion, got in front of me. 2nd Raw Time & 2nd Pax Index, and won CAMC by 1.85 seconds. The grip was phenomenal. I’m not sure how much of that is due to the added 1cm of width, as I now know my old 305 RE-71R tires were pretty badly cooked after 114 AutoX runs and a few track sprints events.

So here is one 315 square recipe, for anyone else looking to make it work:

Ford GT350R springs
Ford Perfomance Pack shock and strut package (M-18000-F)
Vorshlag caster/camber plates
Apex EC-7 wheels, 19x11, ET52
Falken RT660 tires, 315/30r19 square
ARP extended wheel stud kit
Gorilla lugs
1” front spacers
Front camber at -3.1° & zero toe.

*315/30/19 Hoosier A7 & R7 should also fit, as the Falkens are huge...slightly taller and wider than both.
 
61
26
Exp. Type
Time Attack
Exp. Level
Under 3 Years
Bulgaria
I had my best finish ever. Only Tim Aro, a multiple National Champion, got in front of me. 2nd Raw Time & 2nd Pax Index, and won CAMC by 1.85 seconds. The grip was phenomenal. I’m not sure how much of that is due to the added 1cm of width, as I now know my old 305 RE-71R tires were pretty badly cooked after 114 AutoX runs and a few track sprints events.
That is great result congratulation on your CAMC win I can't wait for my SM-10's to arrive though hopefully the 305/30 will work with OEM PP1 suspension with Steeda CC plates ordered ET26 SM-10's so I hope will not need APR Studs but we will see. Thanks for the feedback and again congratulations on the CAMC win.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
5,549
4,081
Exp. Type
W2W Racing
Exp. Level
20+ Years
Blair, Nebraska
..........great run Ghorse and Tim Aro is talented so I am going to have to express that you have to be also!! I am pretty excited about the Falkens, since the Retail Sales Mgr. for them was pushing for something like this for awhile and it does not hurt that he is also an Autocrosser ( and he trophied at the Solo Nationals in the Past )!

Solid run and for those unaware , second in Pax is extremely solid and not easily attainted!!
 
Last edited:
That is great result congratulation on your CAMC win I can't wait for my SM-10's to arrive though hopefully the 305/30 will work with OEM PP1 suspension with Steeda CC plates ordered ET26 SM-10's so I hope will not need APR Studs but we will see. Thanks for the feedback and again congratulations on the CAMC win.
Thanks again. My friend has successfully fitted 305’s in front of his 2016 PP1 without spacers or extended studs. His wheels are not Apex....can’t recall what they are. Good luck getting done. Going from 275 to 305 makes a huge difference.
 

TMO Supporting Vendors

Top