Hello, I would like some ideas of how much work will require putting rear 315’s tires? I am thinking of putting a rear 315/30/18, but my car is already lowered. I don’t want the wheels to stick out the fenders. I have heard that people have rolled their fenders and did some hammering in the inner wells. Will this be very difficult to make the 315’s to be inside, without sticking out? How much hammering does it need inside the well and rolled up the fenders? Will it be a problem if the car is lowered? Also, I talked to the guy if they can widen my rims to 18x11” in order for the 315’s tires to fit on the Ruff 281 rims. The guy told me it would cost $400 to make it widen for both rims. Does this sound a good deal to you? Or any other places that I can look up for a good deal? The place they told me for $400 from this website http://www.fixrim.com/ and http://www.weldcraftwheels.com/ for $450. The rear rims I have now is Ruff 281 with offset 45mm. Also with doing some efforts, will the tires be able to stick inside without sticking out the fender? I just couldn’t find enough information on 3rd gen that owners have done some work to their 315’s tires on the rear in order for the tires to stick inside the wells. I know with some hammering inside the wells and rolling the fenders, but do you think it will work while the tires stick inside and my car is already lowered? Any advice and pictures would help? Let me know thanks.

with the correct offset/or backspacing what ever you want to use, it is possible to put 315's on the back. the majority of the clearance work will need to be done on the bump stop area, you may need to remove it and weld a flat plate back in. also the front of the wheel house needs to be massaged inward, hammering/heat should be enough to make it work, though cutting and some fab would make a nicer job. the tires will get real close to the lower control arms, aftermarket tubular ones will help a lot in this area, and adjustable panhard bar will also help, with it you will be able to make darn sure the rear is centered in the car so minimize rubbing one one side or another.
Im running 335/30/18 rears, they are tucked up real nice, no rolling of the fenders or anything and no rubbing, but it was a LOT more cutting and fab work, custom parts, not fun. Im lower to the approx. height of the ebaich prokit.
rolling the fenders will depend on how low the car is.

On a stock width rear, ideally you would want the 18x11 wheels to have 7.5" of BS from the rotor to keep them tucked, things will be tight. If you remove a rear wheel on your car and grab a straight edge about 28 inches long, you can lay it across the rotors face and measure back and see where you need clearance, this is a good time to measure to the control and and see what i mean about clearance there. That will give you an idea of the work involved. whether you need to use a spacer depends on the specs of the wheel you have chosen. What width do you have, you didnt mention it?

as for wheel widening, i had mine widened by a local shop, 18x8 as they started life and i had them widened to 18x12, it cost me 500 bux to widen both, without refinish work, i only had them widened to the inside of the car, and since the wheels are aluminum i opted to leave the weld-beads as they were to keep all the strength in the weld as possible.

there are actually quite a few people here with 315's on the rear, though usually done in the 17" size on zr1 wheels, most of them fit without much trouble other than what i already stated, but they usually sit flush with the outside of the car, not sticking out, but not "tucked" either.

this is a shot straight down the wheel, see its tucked in reasonably


and as far as clearance, you will need 1" less than this pic, notice the control am is offset and IN the wheel


you dont need to clearance to this extreme, but here it is anyway, another opportunity to whore out some pics


How this helps
Phil

Thanks for replying. Wow, I wouldn't mind a 335's, but with all that work eh.

I do have the panhard and lower control arms adjustables.

I will be getting the rear rims that are 18x9.5" and then I will take it to a shop to widen it to 18x11". Do you know what offset is the best should i get, I have a choice to pick either 40mm or 45mm offset. So which offsets should I go for? Is the lower the mm offsets better?

If I do remove the bump stop area, it is worth having a bump stop?

Thanks, Scott

http://www.thirdgen.org/techboard/su...ighlight=17x11 (Mufflex 4" and 17x11 zr1s installed)

he used 50mm offset and a 1" spacer, no mods at all, just rolling the fender, buit they are FLUSH

search this fourm for 17x11 and you will get tons of stuff


I like backspacing better than offset, it just confuses me for some reason. there is positive and negative offset to be sure to get the right one.

as far as wheels, mine were originally 18x8 with 4.5" of BS, which i believe is 0 offset? and the outside of the rim sat exactly where i feel they should be, so 18x9.5 should have something like a 25mm offset to sit the same way, though i still dont know if that would be positive or negative?


I dont have a bump stop, no problems yet. **fingerscrossedknockonwood**

86ta, im trying to put a 325/50/15 drag radial on a 10''x 15'' rim on my formula. everyone is telling me it cant be done without a mini tub and i dont want to gut the car in order to do it. do you think its possible? how much work do you think is involved? thanks

thats a big tire, you need a mini tub sorry

ok, but how were you able to fit your 335 in there? is the problem the difference in the profile?

look at my picture in the 2nd post, third one down. thats my car, notice anything missing in there? like a LOT of sheetmetal and springs? the car is minitubbed

86, I need more pics of your car ASAP thing is sick!

I am wondering if is worth having a bump stop? Anyone?

Let me know please.

depends on what you do with the car and how low you make it. I sit the height of a prokit and i havent had any issues with bottoming out. If the car sits really low, then they would be a good idea so you dont damage things when you bottom out. If you remove the factory stop area you can always fab on up inboard a little.

also I searched this a while ago a lot of people are running bump stops on the rear shocks. You will have to search to get more info but it's out there.

Thanks, any ideas how I can install the new bumpstop somewhere on the car, while my car is lowered? Pictures would help thanks.

I think a 325 would fit. Right now I have a 29x12.5 mt tire. The tread sits inside the wheel well, but the bulge sits slightly oustide. Its a 13.1 section width. A 325 is 12.8. My rims are 5.5 bs, I had to do some hammering and cut the bumpstops.

The tires do stick out a little farther than I like, but its not bad. A 315 would look much better, and you not losing much tire. I have a little over an inch from the tire to the control arm, which is the closest point, so you COULD maybe use a 6 bs rim, but you would definitely have to cut a good amount of metal out of the well, I'm right at the limit I think.

I'll be changing tires to et streets, same size, but are actually 1/2 inch skinnier section width, so I think it'll turn out ok.

I'd stick with the 315.

I've got 295/50/15s for my rears, no tubbing necessary.

Thanks, I have the lower control arms adjustable, pan rod adjustable, and the lower brackets.

So, I am assuming I would be okay, to remove the "bumpstop" and not having to worry about the car hitting going over speed bumps while my car is lowered? Or should I install the new bumpstop somewhere on my car?

Thanks.

I dont think you'll need em. Lowering springs are usually stiffer than stock, so you axle should never come close the stop. Also with your car lowered, I'm sure you'll be going over speed bumps slow, hell, I was worried about my gfx at stock height.

I was thinking where I can relocate the bumpstops after I remove the old bumpstops to put rear 315's tires.

I have seen this site and not sure what it is. Hope someone can help me what these red are in the blue spring and the other picture? Are these bumpstops and will it past safety?
http://www.injuneer.com/images/photo...s/FendMas1.jpg

Please let me know thanks.

Those are air bags. They are primarily used for a better launch at the drag strip.
They stiffen the rear & can preload the suspension to better control the torque reaction at launch.