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Swapped out the original salad shooters for some sweet 18 inch ESR wheels. The back spacing wasn't perfect but I ordered them anyway. Now the rear tires bottom out on a rare occasion. I need to stiffen up the rear AND I'd like to lower the entire thing. Any suggestions?
Last edited by PoprocksC4; Aug 21, 2018 at 03:36 PM.
general principal is stiffer spring, then you can lower ride height. Never did this on a C4 vette but it worked fine on my 87 grand national with 295/50's on it.
Can you tell where it's touching? It should be able to compress all the way to the bump stops without any tire rub. What size and offset are the rear tires, and what tires size are you running back there? It's hard to tell from the pic due to angle and proportion, but it sort of looks like you don't have enough offset and/or the tire is taller than stock.
Do you mean the suspension is hitting its limits or the tires are hitting the body? It looks like the tires might be hitting the body from your picture.
Do you mean the suspension is hitting its limits or the tires are hitting the body? It looks like the tires might be hitting the body from your picture.
yes. The tires are hitting the body. Installing some new shocks this weekend. We'll see how that goes.
yes. The tires are hitting the body. Installing some new shocks this weekend. We'll see how that goes.
That's not going to stop it, although it may reduce it. Your problem is that you don't have enough offset, and the tires poke outside the fenders. Also, the tires appear to be too large in diameter. Again, what width and offset are the rear wheels, and what size are the rear tires?
oh yeah I know the offset is wrong but the diameter is only about 1/2 inch over stock. I'll look at stiffening the rear suspension first. I just bought them and they look super.
Last edited by PoprocksC4; Aug 19, 2018 at 12:15 AM.
Youre not really going to stiffen the rear suspension without changing the transverse spring to a stiffer spring. Shocks dont change ride height.... they can have valving that makes them compress less which could help some. The solution is to get wheels that fit inside the wheel wells. (correct offset)
My rears are 19x12 with 345/30’s. I’m on coil overs as well. Dint have any issues “bottoming out” but did have to do some minor trimming on the inner fender lining. So it can be done. Stiffer springs and new shocks might work.
My rears are 19x12 with 345/30’s. I’m on coil overs as well. Dint have any issues “bottoming out” but did have to do some minor trimming on the inner fender lining. So it can be done. Stiffer springs and new shocks might work.
Did the ZR-1 have coil overs stock? Can you recommend a coil over set up? AND thanks for sharing your wheel size but do you know your back spacing? AND your ZR-1 is an inch and a half wider on either side, so I probably can't get a 345 up there. 305 max according to JDC.
THANKS FOR YOUR INPUT.
One of coolest things about a Vette, it just makes people smile when I drive by. I'm not bragging.
I don't think that's what he meant by ..as well. He just meant, in addition to.....
Man, you guys are super helpful. I just inherited the Vette from my father. So I'm learning alot. It's been sitting for 8 years. Only 36k. Bone stock.
That's not true. I and others have been able to fit 315 width tires at all four corners of a C4 on 11" wheels with the proper offset. For an 88-96 C4, that means 50mm of offset. I've asked twice what your wheel and tire dimensions are. It appears you have too little offset, and there's no way to fix that (i.e. you can't add spacers like you could if you had too much offset). You can't spring and shock your way out of this problem.
Last edited by MatthewMiller; Jan 4, 2019 at 06:35 PM.
Thanks Poprocks! No the Z did not come with coil overs and I know the extra width helps with wider meats. I was just letting the OP know there’s possibilities out there. As other have said 315’s are popular. I have a set of Qa1 coil overs I got from VanSteel. They are very well made imo and were a straight forward install.
That's not true. I am others have been able to fit 315 width tires at all four corners of a C4 on 11" wheels with the proper offset. For an 88-96 C4, that means 50mm of offset. I've asked twice what your wheel and tire dimensions are. It appears you have too little offset, and there's no way to fix that (i.e. you can add spacers like you could if you had too much offset). You can't spring and shock your way out of this problem.
18x9 /10 30/25mm offset. (Just looked it up on E bay)
I really like the look but I'm sure you're correct. I didn't have enough information before I ordered the wheels. Didn't know what I didn't know. Ya know?
I'll try the new KYBs and see if it helps at all and post my results. Current shocks are 25 yrs old. Can't hurt. I was hoping coil overs might cure the ill. But that's not inexpensive either.
OK. 11 inch wheels with 50mm offset and 10 inch with ?mm
that sounds cool. On a regular C4? Hard to find?
Thanks Poprocks! No the Z did not come with coil overs and I know the extra width helps with wider meats. I was just letting the OP know there’s possibilities out there. As other have said 315’s are popular. I have a set of Qa1 coil overs I got from VanSteel. They are very well made imo and were a straight forward install.
Great. I'll look into the coil overs. Being my late father's Vette, it's become a member of the family. I want to treat it with love.
OP - A quick glance ESR on eBay and I only saw 5 X 120 which isn't correct for a C4 either. I believe I'd try to sell these locally and decide on a purchase that you could confirm here before the buy. Easier to take a loss now with them somewhat NEW than wait until later. Maybe mention all of the wheel specifics or post a link to what you bought. Coil-overs aren't a solution for you and there's 'no need' for them. You don't need to do the max 11" @ 50 either. There's many others that should suit you I'd think that would afford a much better fit for a 'driver'.
18x9 /10 30/25mm offset. (Just looked it up on E bay)
I really like the look but I'm sure you're correct. I didn't have enough information before I ordered the wheels. Didn't know what I didn't know. Ya know?
I'll try the new KYBs and see if it helps at all and post my results. Current shocks are 25 yrs old. Can't hurt. I was hoping coil overs might cure the ill. But that's not inexpensive either.
OK. 11 inch wheels with 50mm offset and 10 inch with ?mm
that sounds cool. On a regular C4? Hard to find?
Yep, 25mm offset is never going to work on a later C4. You might be able to get away with it on an 84-87 C4, although it would have to be checked. But maybe someone with an early C4 would buy these from you.
I'd say that with a 10" wheel you have window of acceptable offset from about 45-60mm. I'd still look for something in the middle of that range. If you have too much offset, you can always correct it with spacers. But not if you have too little.
Suspension / OFFSET issues
