Bobac455

I have a 1970 Cutlass convertible with oversized tires on the rear. With the correct coil springs (correct meaning stock height, part #, etc.) the wheel well openings scrape the tires when going over a bump. If people are seated in the back it is even worse. I have plenty of clearance when the car is unoccupied and standing still. I'm wondering if there is a higher rate spring that still provides the correct height. I have an e-mail into Eaton Spring but they are closed for the night. They only show one spring for my vehicle. I'm hoping the W-30 or 442 might have had a higher rate rear spring. Does anyone know of such a thing? If not, what are my options without putting smaller tires on the car. Is there a helper spring that clamps around the shock? Would air shocks fix this without making the ride super harsh? Thanks ahead of time.

BlackGold

What will fix it is using wheels with the right offset/backspacing. Do you really want your car sitting any higher and/or riding any stiffer? I bet not. And even if you raised it an inch, that's not enough to keep it from hitting on severe bumps. You need to move the wheels inward. I'm assuming, of course, that your tires aren't so incredibly wide that you have to have them that far out.

Bluevista

I've heard of guys using station wagon/Vista Cruiser cargo coils?
They get progessively stiffer as they're loaded.
Maybe somebody that has done it will chime in.
I've got a wagon so I have them.
I had air shocks too but it was too stiff and they looked funky so I yanked them off. The car sits fine with just the cargo springs and regular shocks, up a little bit from stock in the rear but that's okay.
Air shocks to support the weight instead of the springs isn't good.

Blk71SX

there's the air shock route with an onboard compressor. raise or lower as needed

Bobac455

When I bought the car it sat up at least 2 inches higher than it is supposed to and it looked stupid to me. I was told it had vista cruiser spings in it. Now I see why the idiot who owned did it. I will experiment and see if I can find a good solution without raising the height and without making the suspension too harsh. If there is no relatively cheap way to do this, I'll probably resort to buying the correct diameter tire. The backspace offset is extreme too but the tire fits inside the wheelwell and look like its in the right place. That's a good idea that I hadn't thought of though. One inch less backspace would probably do it. Thanks for your comments.

Bobsw32

A cheap fix is installing a set of air bags in your coil springs.... The air bag does not raise the ride height and will not let the spring settle when loaded... Easy to install. just slip them inside the springs...Inexpensive, under $90.00.


A much better fix than air shocks....I have them on all my Cutlasses

Blk71SX

the air bags I've used lifted the rear. I used them for the same purpose the OP has

TripDeuces

I used station wagon springs off a Buick I think. This was on my 70 Cutlass. Raised it less then an inch and the ride was fine.

Bluevista

Dang...I never even thought of airbags.
Looking at your sig pic the wheels do look like they have an awful lot of offset, looks funky IMO.
That has to be hard on the rear axle bearings having them hanging ten like that?
Even with the fixes it still may bottom out with a load when you go over a bump or dip and trash your quarters and tires, could be dangerous.
Camaros were known for oil canning the quarters when that happened, it only takes once.
The most elegant solution (besides having your rear end shortened and tubbing it ) would be to get the correct offset rear wheels and new tires if those won't work.

Cecil Anderson

I have used the air bags inside the coils and works great. Let air out and ride is same as usual. Air in to haul cement and bricks..put something on the seats to protect them Andy

AZ442

When I put new springs on mine I used MOOG CC501 as recomended by MOOG, the ride was great but they lifted the rear 2" and reminded we of the 70 442 I had in 1977 with air shocks pumped up. I have removed them and reinstalled the originals.

Bobac455

Thank you all for your comments. It really helps hearing about what worked and what didn't work. Should save me lots of grief. I believe replacing the rear wheels with the correct backspace is the best alternative. Air bags would be the next step if this doesn't correct the problem. I don't want to prove the theory that "Once is all it takes!"

extreme1

Maybe go get the inner fender lips rolled as well, Tire Rack sells a tool for just such a process.