Shelby CS5 wheels on an 07 Shelby GT

[ShelbySteve]

Have an 07 Shelby GT that is lowered (not crazy low but i can tell it isn’t stock as I bought it this way. Currently running the same gen 18x9.5 GT500’s wheels. I tried doing some searching and I’m sure it’s been asked 100x so don’t roast me too bad lol. Looking at getting the 19x9.5 in the front with 34mm offset and 19x11 by 50mm in the back. I’ve read that an adjustable pan hard bar may be needed but Shelby’s website that a watts link may be needed and I’m not ready to drop a grand just to run a certain wheel. Anyone ran these and how bad do the rear wheels/tires hang out of the fender?

edit* and I plan on running the s550 or the GT500 4 piston Brembos

 

[AHaze]

Your current wheels have a 45mm offset so the 9.5 wide 34mm offset fronts will sit 11mm farther out (same width so the offset is the only difference) and the 11 wide 50mm offset rears will sit 14mm farther out (38mm of extra wheel width, half of which is outboard of the bolt face, so 19mm, minus 5 extra mm of offset.)
I also have GT500 wheels on my car and might be able to tuck an extra 11 mm up front with enough camber but 14mm more out back would definitely poke if matched with a tire big enough to justify the 11" wide wheel.

 

[ShelbySteve]

Your current wheels have a 45mm offset so the 9.5 wide 34mm offset fronts will sit 11mm farther out (same width so the offset is the only difference) and the 11 wide 50mm offset rears will sit 14mm farther out (38mm of extra wheel width, half of which is outboard of the bolt face, so 19mm, minus 5 extra mm of offset.)
I also have GT500 wheels on my car and might be able to tuck an extra 11 mm up front with enough camber but 14mm more out back would definitely poke if matched with a tire big enough to justify the 11" wide wheel.

Guess i should’ve posted the available tire sizes on the Cs5’s with what are on the car now. I have 255 on the front and 285 on the back. According to cjponyparts site I can get 255 front and 275 rear, or 305 in the rear which I think would poke out pretty bad. I also have the option to go all 4 9.5” wide I can go 255 front and 275 rears. I went outside and measured and the extra 11mm up front seems as though it’d put the tire even with the top of the fender. If I went with the 9.5” on the back and went with 275’s while I have 285’s on the back now, would the smaller tire and increased offset essentially put me sticking out an extra mm?

edit* nvm found the will it fit site and see that the rear will still stick out 11mm more. Thanks for the help and I’m off to find some different wheels lol

 

[AHaze]

A 10" wide wheel with 42mm offset and a 285 tire all around is a good starting point. That combo tucks a bit in the front (assuming you've added some camber) and sits fairly flush out back. You can certainly go wider (11" wide with 305s all around has been done) but it starts to involve different offsets front to rear or spacers or putting up with some poke.

 

[ShelbySteve]

A 10" wide wheel with 42mm offset and a 285 tire all around is a good starting point. That combo tucks a bit in the front (assuming you've added some camber) and sits fairly flush out back. You can certainly go wider (11" wide with 305s all around has been done) but it starts to involve different offsets front to rear or spacers or putting up with some poke.

I found a set of 20x9.5 40mm offset and 20x11 50mm offset super snake wheels for a good price. With they fit without any issues? I tried to do some searching and found plenty of guys running 20x11 outback but didn’t see any specific offsets.

 

[AHaze]

I found a set of 20x9.5 40mm offset and 20x11 50mm offset super snake wheels for a good price. With they fit without any issues? I tried to do some searching and found plenty of guys running 20x11 outback but didn’t see any specific offsets.

Rears will be the same deal as the rears from your first post. Gonna sit 14mm farther out than the stock GT500 wheels.
A lot of the aftermarket 11" wheels that were supposedly designed for this chassis poke on the back. The only reason I can think of for this is to prevent an inner sidewall rub caused by the lateral slop and poor static centering of the stock panhard bar.
At least two companies that target the time attack / road race crowd have developed 11" wide wheel packages that fit inside the wheel wells (once the axle is properly centered) but they're understandably protective of the offset numbers. Based on measurements I took on my car, I would guess the proper rear offset for 11" wides would be in the mid to high 50s. I would suggest you contact the pros rather than order custom wheels based on my rudimentary measurements though.

 

[ShelbySteve]

Rears will be the same deal as the rears from your first post. Gonna sit 14mm farther out than the stock GT500 wheels.
A lot of the aftermarket 11" wheels that were supposedly designed for this chassis poke on the back. The only reason I can think of for this is to prevent an inner sidewall rub caused by the lateral slop and poor static centering of the stock panhard bar.
At least two companies that target the time attack / road race crowd have developed 11" wide wheel packages that fit inside the wheel wells (once the axle is properly centered) but they're understandably protective of the offset numbers. Based on measurements I took on my car, I would guess the proper rear offset for 11" wides would be in the mid to high 50s. I would suggest you contact the pros rather than order custom wheels based on my rudimentary measurements though.

I’m getting a good enough deal that I’m going to go ahead and make the jump and get them. I’ll post pics if I mount them lol. Thanks for the help

 

[xeninworx]

The S500 4 piston brakes are kinda wide. Wider than the 4 piston Brembos. The hub on the S550 sticks out further by 3/4” so putting the S550 brakes on the S197 will come closer to the spokes.

 

[ShelbySteve]

An update and a question...did some searching and seems most prefer 305’s on 11” wide wheels for the rear. Also read some hate 285’s on 11” wide wheels. My rears are 20x11 with a 50mm offset and want the sidewall to sit flush with the rim lip as possible. Prefer the 305’s because of a broader tire selection, but what is everyone’s opinion or experience on 305/30r20 and 285/30r20 on an 11” wide rear wheels on an 07 s197?

 

[Norm Peterson]

Here's a comparative plot based on nominal sizes, 305/30-20 vs 285/30-20, both on 11" wide wheels of +52 offset.



And the same, with the offsets staggered so you can see the individual tire shapes a little better.



There isn't any huge difference as far as sidewall "bulge" is concerned. The 285 sidewalls lie just a tiny bit inside the wheel flanges (IOW, narrower), while the 305 sidewalls are just outside them. The difference is on the order of 3/16", which isn't all that obvious if you're not looking for it.

Here's what 285/35-18 looks like on an 11" wide rear wheel, offsets somewhere in the mid +50's. The front wheels and tires are the same sizes, but the wheel offset is different (guessing it might be somewhere around 20mm less positive). Around -2° camber up front, no lowering, and nothing rubs.




Norm

 

[ShelbySteve]

Here's a comparative plot based on nominal sizes, 305/30-20 vs 285/30-20, both on 11" wide wheels of +52 offset.

View attachment 75441

And the same, with the offsets staggered so you can see the individual tire shapes a little better.

View attachment 75442

There isn't any huge difference as far as sidewall "bulge" is concerned. The 285 sidewalls lie just a tiny bit inside the wheel flanges (IOW, narrower), while the 305 sidewalls are just outside them. The difference is on the order of 3/16", which isn't all that obvious if you're not looking for it.

Here's what 285/35-18 looks like on an 11" wide rear wheel, offsets somewhere in the mid +50's. The front wheels and tires are the same sizes, but the wheel offset is different (guessing it might be somewhere around 20mm less positive). Around -2° camber up front, no lowering, and nothing rubs.

View attachment 75446


Norm

Thanks man. Been looking forever for a similar setup and had a hard time making up my mind. Went with 285’s as mine is lowered and want to make sure 285’s are good before going wider next time. My fronts are 255 on 9.5” wheels. Getting them put on Friday if my tpms sensors get here tomorrow and I’ll post some pics.

 

[Norm Peterson]

I should probably add that since the above picture was taken, I lowered the car about half an inch. Nothing rubbed then, either. Both before and after the lowering, car use included a number of HPDE track days where the car was seeing considerably more cornering g's than you'd ever see in street driving (like more than double even if you drive with a fair amount of "enthusiasm), and more nose dive under braking than you'd see on the street in anything other than a full-on emergency stop.


Norm

 

[MrBhp]

305/35-20 on Shelby CS2's 20x11 55mm offset rears. 275/35-20 on 20x9 30mm offset front.
Not exactly the same offset as the wheels you are looking at. But close enough to give you an idea of what you will end up with. Another 5mm on the rear probably won't poke. The front's do not poke, but I'm running -2.75 camber.
Please excuse the filthy car. It just made a 6,000 mile trip.

 

[ShelbySteve]

305/35-20 on Shelby CS2's 20x11 55mm offset rears. 275/35-20 on 20x9 30mm offset front.
Not exactly the same offset as the wheels you are looking at. But close enough to give you an idea of what you will end up with. Another 5mm on the rear probably won't poke. The front's do not poke, but I'm running -2.75 camber.
Please excuse the filthy car. It just made a 6,000 mile trip.



View attachment 75462

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Looks damn good. I’ll get some pics of mine up Saturday hopefully as I’ll be driving in the rain to get them mounted tomorrow. Been sitting on the wheels for a couple of months as I spent my tire budget on them too lol. Found some 50th anniversary super snake bright silver wheels brand new for a steal.

 

[ShelbySteve]

Here’s one from the side right after I got them mounted. I’ll get some more of the fitment ones posted this weekend when I get it cleaned up.

 

[ShelbySteve]

20x11 50mm offset rear with nitto n555 g2 285/35r20 tires. Fitment is great for me although it seems like I may try a different tire next time to see if they will sit over the lip of the wheel.

 

[MrBhp]

Here’s one from the side right after I got them mounted. I’ll get some more of the fitment ones posted this weekend when I get it cleaned up.

View attachment 75516

Very Nice.

 

[ShelbySteve]

Very Nice.

Thanks. Big brake kits are next on the list

 

[Norm Peterson]

20x11 50mm offset rear with nitto n555 g2 285/35r20 tires. Fitment is great for me although it seems like I may try a different tire next time to see if they will sit over the lip of the wheel.

A tire with a somewhat more robust "rub strip" may get you closer to what you're looking for.

At least in 285/35-18, Michelin's PSS puts the rub strip right at the outer edge of an 11" wide Forgestar F14. A straightedge laid across the outer face hits both the wheel and the rub strip (four total points of contact) simultaneously. I just checked this on the car; the picture below had to be taken at a slight angle to see the wheel.




Norm

 

[ShelbySteve]

A tire with a somewhat more robust "rub strip" may get you closer to what you're looking for.

At least in 285/35-18, Michelin's PSS puts the rub strip right at the outer edge of an 11" wide Forgestar F14. A straightedge laid across the outer face hits both the wheel and the rub strip (four total points of contact) simultaneously. I just checked this on the car; the picture below had to be taken at a slight angle to see the wheel.

View attachment 75530


Norm

That may be the route I have to go then. I had some Firestone wide ovals on my f body years ago that covered the rim lip well. Been out of the game about 5 years now and just getting back in it a few months ago.