midlights

Hello,
I recently purchased J's front fenders & Circuit Garage rear flares for my S with the goal of getting some seriously wide meaty tires on the car. The car is LS swapped and is currently running 17x8" wheels off a 1997 mustang with 255 square Nitto 555r. I know weird setup but they bolt right up and sometimes you gotta make things work to get your car on the road. I'd like to run a 18x10f 18x12r 265/305 front/rear tire setup with my fenders and flares, but I'm having trouble figuring out the proper wheel offsets and tire specs needed. I do not want to run crazy stanced out camber and I'd like to be able to use off the shelf wheels if possible. I have honestly no clue when it comes to these things. I come from the late model BMW and GM world where you go to places like Tire Rack and they sell wheel and tire packages in those widths for the car and there's minimal effort involved. If anyone can guide me as to what offsets I need to run and what wheels are available in those offsets I'd greatly appreciate it.

s2000Junky

Lets start here. The J's front fender I believe is 40mm wider then stock correct? The rear 75mm?

Jumping ahead, I would probably just go for a 315 in the rear, you have more then enough room. You have more room up front as well to run a bigger package if you wanted, but not as imperative in my opinion. I believe you are going to have quite a few more tire choices/compounds to choose from in a 315/30/18 and those wide ass fenders will still make that tire disappear under there. You could do 10.5-11/285 up front if you wanted. But 10/265 works too. I guess part of the issue will be what wheel widths/offset on the shelf are available to you, and you can size the tires around that somewhat. This isn't the ideal way to go about this, as you ideally would pick the best tire size first and then size the wheel width most appropriate to that. I can tell you right off hand, what you exceed 10" width, the off the shelf options are next to nothing for this car, so expect to be shopping for a custom multi piece wheel where you can build your own width/offset. Or do what I've done and take a stock off the shelf wheel such as a Enkei RPF1 in my case, start with the right offset and then cut and weld additional width to the inside to widen it. That route depending on the wheel in many cases will be lighter and less expensive in the final product. Weldcraft charges $200-250 per wheel to have widened, coupled with cost of the wheel, you might be in it $500-600 per wheel. A custom multi piece wheel could be near double that. x4. Another option to reduce some cost, might be sticking with 17's. There is a sizable amount of tires available in 275/40/17 and 315/35/17 to build a front/rear staggered set up such as what you are doing. At an average of about $100 less per tire, its a consideration.

Just some options/food for thought for you.

lolS2K

I've also got an LS swapped S. It's currently on 17x9 square and, as you can imagine, has very little grip. I've got Meisters ordered in 18x9 +45 and 18x11 +65. Will be running stock body with rolls and bumper tabs. I had a lot of help from S2000Junky. You don't necessarily need to go wide body to stuff a bunch of rubber under the car, it just needs to be carefully thought out.

midlights

Thanks for the advice S2000junky, you're spot on with the fender specs front and rear. And you called out the main problem I'm running into at the moment. I have plenty of wheel selection up front but finding an off the shelf wheel with the correct width and offset for the rears is near impossible. I'm going to definitely hit up weld craft about widening wheels but as I live in Hawaii I have shipping costs to take into consideration compared to just buying a custom setup. I do like the thought of fitting 315s. I've got my front specs figured out as a lot of folks run the js fenders and I've been able to figure out what I can fit from searching these forums. Any idea how I'd have to spec my rear wheels to run 315/30/18?

s2000Junky

These tires are well regarded and also happen to be the least expensive so I would probably go for these. The fronts would be 275/35/18 just fyi.

https://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=g-Force+Rival+S&partnum=13WR8GFRS&vehicleSearch=fals e&fromCompare1=yes

Taking the max recommended rim width in account for this particular tire (11.5) to have a good looking/working rear fitment you would want your offset on that 11.5" wheel to be at or near 0 offset. That's based on the rear being 75mm over stock. How aggressive you size the front wheel/offset will help you determine give or take +/- 10mm in the rear offset if you want it to sit right. I prefer things to look even or slightly more aggressive/less offset in rear (vs the front, which seems to happen sometimes with off the shelf wheels people select) Your rear fenders are already 25mm more aggressive then the front though, so id try and stick to even as possible (as in the wheel protrudes the same amount based on the fender line appearance front and rear.

This is a great tool you can use to play with widths/offsets. You can use the known oem wheel widths/offsets as a control and then punch in your questionable new size to see how the fitment changes based on your new fender widths. Ive punched in your front and rear sizes based on 40mm wider front and 75mm wider rear. You can play with wheel widths and offset independent off one another to also get same outer fitments, and your tire size should be mated to wheel widths. I prefer max recommended wheel width to tire width for best look and performance http://www.willtheyfit.com/index.php?width=315&aspect=30&diameter=18&wheelwid th=11.5&offset=0&width2=275&aspect2=35&wheel_size= 18&wheel_width=10-5&offset2=25

To add, if you have to, based on finding proper offset with wheel options, you could use spacers. Generally no more then 5mm spacer should be used without integrated wheels studs, and anything between that and 10mm will need longer wheel studs pressed into hubs, beyond 15mm spacers you can use the integrated studs that come on the spacers. For example, if you find a set of wheels that you love with the proper width stagger, but the rear offset isn't aggressive enough and will look sunk in being a 11.5 +25, you could integrate a 25mm spacer to push it out to where it needs to be to sit flush with fender.

thomsbrain

midlights, where did you find your CG rears? I've been wanting to do the same combo when I get enough disposable cash. In my case I'd run 295 on 18x11 square or 295/315 on 11x18 and 12x18. It does look like custom rims (CCW, Forgestar or widened) are the only way to do this combo. Tire options would be Trofeo Rs, R1s or A7s.

MaximumAttack

Anyone know how the Top Fuel/Voltex S2000 is able to make their 18×11.0J +15 Advan TCIIIs with 295/30/18 all around fit? Is it just ridiculously wide over fenders, a special combo of that & spacers, or what?

295 all around is my eventual goal. Would like to figure out a way to do it without going with custom wheels. There are a lot of 18x11 options out there around the +15 to +22 range.... (Volk, Advan, etc.)

Manga_Spawn

What on earth would spacers do to make them fit? Spacers only push the wheel farther out. The Top Fuel Voltex car is completely custom built and yes very wide compared to stock. It also has something like 700 hp. So I would say they manage to make them fit but having a nearly unlimited budget and the means to fabricate any part they so choose.

MaximumAttack

Inner clearance to stop the wheel/tire from making contact with the coilovers...

s2000Junky

The point was you dont need even more inner clearance because a 11" + 22 has a shit load already. The issue is getting the outer fenders wide enough to accommodate that wheel width/offset. Adding spacers will therefore make fitment more challenging.