305/35R19 with BMR springs?

[SlowPony46]

Hello,

I have a 2008 GT that I’ve had since new. I sort of lost interest in it s few years ago, stopped looking at forums, etc. this year I’m getting interested in it again so I’m changing some things around.

I have deep dish bullitt wheels from American Muscle, 18x10 and 18x9 with 285/40 and 255/45 tires.

Car is lowered with BMR springs. I see the springs BMR lists are all 1.5” drop. I could have sworn mine were less, but it was 10 years ago. Maybe they had different options back then. To be safe let’s say it’s lowered 1.5” or less.

I want to change my wheels. Wheels I’m looking at are MMD Zevin in 19x10 and 19x9. I’d like to run 255/40 front tires as they are identical to what I have now. The problem is that the recommended 285/35 rear is over an eighth inch shorter than the front (and my current tire). I don’t like this, and the fender gap is already pretty big. Not many companies make a 295/35, but the tire I want is available in a 305/35 which would be slightly bigger than the front and hopefully fill the wheel well nicely, but I don’t want rubbing issues.

American Muscle says it will most likely fit but can’t say for sure. Seems like a lot of people are running that size on 19x10s of various style. This wheel has a 45mm offset.

So, has anyone successfully run a 305/35r19 tire on a 19x10 wheel with 45mm offset, with BMR springs, or am I asking for trouble?

Also has anyone used these wheels specifically and how do you like them?

Thanks!

 

[Gabe]

A 10" rear wheel with 45mm offset will be a great fitment back there.
A 305 tire really wants a 10.5-11"-wide wheel, but it fits OK enough for the rear.
Some sidewall bulge, not really a full 305 contact patch, but OK.

As far as the tire sizes you're considering, look into 265/40/19, a stock front size on some GT500's.
The 265/40/19 is 27.3" tall.
The 255/40/19 is 27.0" tall.
The 305/35/19 is 27.4" tall.
The 285/35/19 is 26.85" tall. A little shorter than the 255/40/19 but only half that difference will translate into vehicle height since that difference is for the whole tire, and it mounts to the car in the middle of it. Car would sit about 1/16"-1/8" lower in the rear because of tire size. This is usually not an issue since most cars have a slight rake to them.
Another option would be a 285/40/19, almost 28" tall. They'll fit fine back there and add to the rake of the car.

I've run 27-28.4"-tall rear tires, 18,19,20" set-ups.
Currently on 18's. 285/40/18 fronts with 305/40/18 rears.

 

[07 Boss]

I run almost a 29" (28.8") tall tire on my Cobra R springs and my ProKit springs. Never once rubbed with the 45mm offset. It looks close but there is actually more room than it appears. The tires you are looking at are over an inch shorter so I think you will have plenty of room.

 

[SlowPony46]

A 10" rear wheel with 45mm offset will be a great fitment back there.
A 305 tire really wants a 10.5-11"-wide wheel, but it fits OK enough for the rear.
Some sidewall bulge, not really a full 305 contact patch, but OK.

As far as the tire sizes you're considering, look into 265/40/19, a stock front size on some GT500's.
The 265/40/19 is 27.3" tall.
The 255/40/19 is 27.0" tall.
The 305/35/19 is 27.4" tall.
The 285/35/19 is 26.85" tall. A little shorter than the 255/40/19 but only half that difference will translate into vehicle height since that difference is for the whole tire, and it mounts to the car in the middle of it. Car would sit about 1/16"-1/8" lower in the rear because of tire size. This is usually not an issue since most cars have a slight rake to them.
Another option would be a 285/40/19, almost 28" tall. They'll fit fine back there and add to the rake of the car.

I've run 27-28.4"-tall rear tires, 18,19,20" set-ups.
Currently on 18's. 285/40/18 fronts with 305/40/18 rears.

Thanks for all of the information Gabe. For the 265 front tires, I don’t really want to run a taller front tire. As it sits the front fills the wheel opening nicely while the rear has a gap still. My main concern with running a shorter rear tire is that I don’t want the look of it and I don’t want to increase the rear wheel well gap even slightly, so my hope is that I can move up to the 305. A 305/35 is like .4” taller than the 255/40 so it will fill the opening a little more without being huge. If it will fit.

Your 305/40r18s are about .2 taller than the tire I want to run, which I assume would mean if that fits mine should fit. But is your car lowered, and what offset wheels do you have?

I see that LMR sells SVE wheel kits that have a 19x11” rear wheel with a 50mm offset and they put 305/35s and don’t list any fitment stipulations. If my math is correct an 11” wheel with 50mm offset sits farther out than a 10” wheel with 45 because the extra 5mm in offset is more than made up for by the inch wider wheel. So if those fit, what I want to run should fit right?

Sounds like you’re supporting my theory that it will fit. I just really don’t want to be stuck with tires I can’t use. If they will fit I think it will wind up being a good combination on my car.

I run almost a 29" (28.8") tall tire on my Cobra R springs and my ProKit springs. Never once rubbed with the 45mm offset. It looks close but there is actually more room than it appears. The tires you are looking at are over an inch shorter so I think you will have plenty of room.

Boss, what width tire are you running? Also, you may remember me years ago I had a different screen name (urbanredneck I believe) on another board. I sent you my cam tools to borrow. Good to see I’m not the only one with the same car years later.

Also my car is alloy. How do you think graphite color wheels would look on alloy?

 

[Gabe]

Thanks for all of the information Gabe. For the 265 front tires, I don’t really want to run a taller front tire. As it sits the front fills the wheel opening nicely while the rear has a gap still. My main concern with running a shorter rear tire is that I don’t want the look of it and I don’t want to increase the rear wheel well gap even slightly, so my hope is that I can move up to the 305. A 305/35 is like .4” taller than the 255/40 so it will fill the opening a little more without being huge. If it will fit.

Your 305/40r18s are about .2 taller than the tire I want to run, which I assume would mean if that fits mine should fit. But is your car lowered, and what offset wheels do you have?

I see that LMR sells SVE wheel kits that have a 19x11” rear wheel with a 50mm offset and they put 305/35s and don’t list any fitment stipulations. If my math is correct an 11” wheel with 50mm offset sits farther out than a 10” wheel with 45 because the extra 5mm in offset is more than made up for by the inch wider wheel. So if those fit, what I want to run should fit right?

Sounds like you’re supporting my theory that it will fit. I just really don’t want to be stuck with tires I can’t use. If they will fit I think it will wind up being a good combination on my car.

Yes, my car is lowered, on BMR springs, 1.5" lower in the back.
My wheels are the OEM 2010 GT500 convertible 18x9.5's, I think the offset is 42mm.

I've had 10"-wide rear wheels with 48mm offset and with 305's on them, it fit perfectly.
A 3mm-lesser offset would not have created a fitment issue.

My second current set of 18's are 18x10 with 45mm offset, the rear tires are 305/40/18, they fit perfectly:

 

[SlowPony46]

Thanks Gabe. You car looks great, do you have a side picture?

I assume fitment is the same for 05-09 cars and 10-14 right?

 

[Gabe]

You're welcome, and thank you!
Yeah, fitment should be the same. Springs are the same.
A side shot: