Forgestar dealer says MPSS 315 (and 305s) won't fit

[nhs156]

I've been eyeing a set of F14s for a while for the sole reason of getting wider rubber on the rear. I currently have MPSS 285s on the rear, and would like to go 315.

I've read conflicting opinions on this forum as to whether or not they will fit w/o rubbing or modification. At least one user has claimed they fit "perfectly" with no rubbing or modification (my car is stock). Others have claimed they may stick out from the fenders "a little bit" and/or rub. So I'm confiused.

The dealer says that in his experience the widest tire that can be fit to a GT500 is a MPSS 295 (and 305s in non-MPSS models, as the MPSS is wider than others). Beyond that they extend beyond the wheel arch or require modification.

Som, my question is this: has anyone actually fitted a MPSS 315 rear to a STOCK car (or at least one with stock suspension), and been able to do so without modifiying/relocating anything and without having the tire extend beyond the wheel arch???

Really, I'd like to know what the widest model of MPSS I can put on w/o having to mod anything, and also avoiding the tire "sticking out". Again, I've probably read most of the threads filled with questions and opinions, but have not stumbled upon anything definitive as of yet.

Opinions welcomed. First had experience graciously appreciated!

Thanks in advance!

Edit: the dealer also recommends an 11" rear wheel. Could that be the issue? Would a 315 fit "better" on a 10.5" wheel??

 

[VFORCEJOHN]

this all depends on the wheel you are using and the offset and rim width if it will fit without rubbing anything.

I use 305-35-20 Mickey drag radials on my stock 9.5 inch wheels. they are not ideal for rim width, but they do work

I'd go with a 10.5 or even an 11 if you want to run that wide of a tire and have it lay flat.

 

[nhs156]

Appreciate the response. The dealer is essentially saying that offset isn't the issue - a 315 or 305 MPSS will not fit without rubbing or sticking out from the fenders.... in his experience. This is a perspective I'm having trouble with as posts/opinions on this forum and elsewhere seem to suggest it is possible.

Btw - the dealer is recommending a 11" rear with a 55mm offset and a 295 MPSS. Trouble is, I'm ONLY considering the wheels because I want the tire. I'd prefer stock wheels but recognize they're too narrow, and don't want to widen the wheels either. But if all I can do is upgrade from a 285 to a 295 MPSS by going the Forgestar F14 route, then it definitely won't be worth it, in my book.

 

[TheGovernment]

You could go with nitto or toyo, both their 315s fit fine with the right offset. The dealer is right on the mpss, they are too big to fit in a 315. Maybe if you rolled your quarters though.

 

[Matt in Houston]

What is your driving style, and why do you want the MPSS so bad? It is a good tire, yes, but there are actually several better choices if you want ultimate grip in a straight line (555R/NT05R/MT) or if you want excellent grip to tackle the twisties (R888). All of these tires will out perform the MPSS in their given task.

Also, a wider tire is usually not going to give you more grip in a straight line. It is a myth that is commonly believed on the forums as fact. Tire diameter and sidewall height will give you more forward traction. Width typically helps more with lateral traction. When you go wider you are just making the tire contact patch shorter and wider instead of longer.

On another note, my F14's just arrived yesterday. I went with 18x11 +53 rears and 19x9.5 +35 fronts. Deep concave. Running NT05R 305/45's on the rear. My car is setup as a roll/drag rocket.

 

[Breitling]

On another note, my F14's just arrived yesterday. I went with 18x11 +53 rears and 19x9.5 +35 fronts. Deep concave. Running NT05R 305/45's on the rear. My car is setup as a roll/drag rocket.

In for pics...

 

[nhs156]

The reason I want the MPSS is simply that I believe it to be the best allround tire. I've been using Michelin PSS and PS2s on my cars for the past 10 years, and swear by them. Nothing else comes close for daily driving. The Nitto and MT are too specialized for daily driving - in semi drag radial form. I've cosidered the R888s, but don't particularly like the rounder profile or mileage/wear - they'll get 1/3 to 1/2 the miles vs. the MPSS so end up costing 2-3X more on a per mile basis. Also, I'd like a slightly larger diameter tire front/rear to help close the gap between the tires and the fenders - and to give me more ground clearance. Currently I can't drive my car through a car wash with the MPSS and the front splitter attached as they're lesser in diameter than the stock GYs.

Bottom line, I'm pretty much set on the MPSS. I have an eye on the R888s, but suspect I'll stick with the MPSS. I put 15K miles on the car per year, and use it as a daily driver. Need it to handle well in the dry and wet.

 

[Matt in Houston]

The reason I want the MPSS is simply that I believe it to be the best allround tire. I've been using Michelin PSS and PS2s on my cars for the past 10 years, and swear by them. Nothing else comes close for daily driving. The Nitto and MT are too specialized for daily driving - in semi drag radial form. I've cosidered the R888s, but don't particularly like the rounder profile or mileage/wear - they'll get 1/3 to 1/2 the miles vs. the MPSS so end up costing 2-3X more on a per mile basis. Also, I'd like a slightly larger diameter tire front/rear to help close the gap between the tires and the fenders - and to give me more ground clearance. Currently I can't drive my car through a car wash with the MPSS and the front splitter attached as they're lesser in diameter than the stock GYs.

Bottom line, I'm pretty much set on the MPSS. I have an eye on the R888s, but suspect I'll stick with the MPSS. I put 15K miles on the car per year, and use it as a daily driver. Need it to handle well in the dry and wet.

You're probably right, for an all-around tire they are one of the best. If you are daily driving then the MPSS make a lot of sense. But I will say, I've been running these 305/35-20 555R's for about half a year now and they are excellent, easily could daily them and they can corner a bit too. They will grip better than the MPSS but still last a decent amount of time. I've been caught in a downpour once while on the highway and I was fine. Very surprised actually.

The R888's are pretty wicked. Ran them on my Elise.

Other things to consider, the F14's are lighter than OEM and the wider wheel will fit the 295 MPSS like a glove. And of course, you can sell your OEM's to make up the cost of the F14's if you like. I think the Forgestar's are great bang for the buck.

Here is a pic of a F14 in black graphite. Arrived yesterday...the finish is awesome, pics dont do it justice.

 

[Ray Lucca]

How wide are the F 14's, or can you specify a width when ordering?? Sounds like 10.5"-11" is the sweet spot.

 

[Matt in Houston]

You can custom order if you want. Different sizes, widths, and concavity. Mine took about 12 weeks to come in. Ordered from Paul at Howey Industries.

 

[MovingZen]

I've read conflicting opinions on this forum as to whether or not they will fit w/o rubbing or modification. At least one user has claimed they fit "perfectly" with no rubbing or modification (my car is stock). Others have claimed they may stick out from the fenders "a little bit" and/or rub. So I'm confiused.

The dealer says that in his experience the widest tire that can be fit to a GT500 is a MPSS 295 (and 305s in non-MPSS models, as the MPSS is wider than others). Beyond that they extend beyond the wheel arch or require modification.

Som, my question is this: has anyone actually fitted a MPSS 315 rear to a STOCK car (or at least one with stock suspension), and been able to do so without modifiying/relocating anything and without having the tire extend beyond the wheel arch???

There are people running mpss 315's without issue, some are doing it with the fender carpet removed, some not. The dealer may mean that 315's wont fit with the wheels you want because of the offset(like others have said). That may be the difference, and what's causing the confusion. I'm running the 295 and I'm very lowered. I can drop the fender down past the tire and the car rests on the bump stop not the tire. You should be able to get 315's under there but you may have to get a custom wheel so you can control the offset.

 

[efroeh]

there is two different sizes of 315s one is wider then the other i have 315 the narrow version with a panhard bar to center the rear end. rims are tf 11 wide

 

[Stetler17]

Don't overlook the fact that a 295 is going to look much wider on that 10.5 or 11" wheel than they do on a stock 9.5" wheel.

The MPSS 295 is a really good fit for a 10.5 wheel.

 

[Cman01]

The MPSS 295 actually will fit an 11" wide wheel better than a 10.5" wheel (10.5" is the recommended minimum wheel width for that tire).

I'm running the 295 on my 11" wide Forgelines and the rim protector protrudes out quite a bit, here's a pic:

You can clearly see how far out from the edge of the wheel the 295's stick out. Michelin MPSS tires are sized fatter than what the size says.

The MPSS 315 really should be mounted on an 11.5" wide wheel so it looks square and not too stretched or have too much bulge.

Tony

 

[Tight Lines]

The newer MPSS 315 will not fit. I believe the ones that say it will have an older model MPSS. I probably was one of the first ones with this problem. After going through the install and sharing pics with Howey industries we found out there was a modification to the rim protector that widened the tires even more. I had the correct tires that others said fit and man stuck out of the fenders and rubbed the inner fender. They had to be taken off and I went with 295's. When the 295's came in I measured the rim protector on the new one vs the old ones I had on my SVT wheels and there was over a 1/4" difference from new to old. If you are dead set on MPSS I would go with the 295's as they measure closer to a 305+. If not, look into a more true sized tire. I really think it sucks that tire companies can't follow a simple measurement and be true to it. A 305 should measure 305 no matter what tire manufacturer makes it. Sure would make stuff easier.

 

[Live Faster]

+1 one this ^ Sucks when you spend good money on tires to find out they won't fit due to the size variation between all brand of tires. I'm running the NT555r's in 305 and have a set of MT ET Street Radial II's in 305 sitting in my basement,almost 2" difference in with. Make it simple as stated above!!!

 

[MovingZen]

The newer MPSS 315 will not fit. I believe the ones that say it will have an older model MPSS. I probably was one of the first ones with this problem. After going through the install and sharing pics with Howey industries we found out there was a modification to the rim protector that widened the tires even more. I had the correct tires that others said fit and man stuck out of the fenders and rubbed the inner fender. They had to be taken off and I went with 295's. When the 295's came in I measured the rim protector on the new one vs the old ones I had on my SVT wheels and there was over a 1/4" difference from new to old. If you are dead set on MPSS I would go with the 295's as they measure closer to a 305+. If not, look into a more true sized tire. I really think it sucks that tire companies can't follow a simple measurement and be true to it. A 305 should measure 305 no matter what tire manufacturer makes it. Sure would make stuff easier.

What wheels, sizes, and off set did you try the 315's with? I believe Steve at TF got 315's inside his fenders even with an air lift kit.

 

[Tight Lines]

Forgestar 20x11 +53 rear.

 

[stutter]

Forgestar 20x11 +53 rear.

This! In 2013 I ordered my Forgestar CF10 20x11 +53 with the NEWER MPSS 315/35R20 105(Y). Fit like a glove, slight rub on the inner carpet when going in a driveway....only sometimes tho. I put 6000 miles on those things, ran perfect!

 

[stutter]