97z2801ss

iTrader: (4)

Alright I'm having some issues with my 97 z28 after doing a ton of mods. The car is riding crazy, harsh, rear end jumping all over especially around corners, and its pulling me all over the road to the point where the steering wheel is jerking back and forth. It's making me not even want to drive the car.

The thing that seems to have made the most negative effect is the wheels. I. About to go outside and drive it with the stock wheels on and see if its still doing it. Below is a list of the mods that just went on, the car was fine before this. I'm wondering also if the rear end is way off center or something, or could the lca angle contribute too..?

All brand new

Bilstein shocks and struts, all new mounts seats ect
Bmr lowering springs
Umi front and rear 35/22 sway bars, poly bushings and end links
Umi non adjustable lower control arms, poly
Umi non adjustable panhard rod
Umi strut tower brace

And the wheels, which are strange.. They require big spacers to run the rears for some reason, otherwise they aren't even close to clearing the inner wheel well and lower control arm area.

C6 chrome w rivets, 18x8.5 front 19x10 rear. 245/40/18 and 285/35/19 Goodyear Supercar F1 tires in good shape 40% tread left, worn a little more in the middles from over inflation.

Any help is greaaaaatly appreciated, I. Thinking I need an adjustable panhard for sure, but this isn't normal, it's bad to the point where the handling is unpredictable and unsafe.. Basically a million steps backwards considering all the upgrades that just went down.

Paules94Z

iTrader: (1)

Did you get the front end aligned after the lowering springs? Also an adjustable panhard bar is a must to center the rearend back under the car after lowering.

zerogravity779

iTrader: (1)

Wide tires will find those grooves in the road that your car and all others created with stock tires. When vehicles ride on the pavement, the weight of the vehicles, over time will "grooves" the driving lanes. Your new wider tires will make your rear end "dance" sway all over the lane. So the tire will "grab" the side of the groove, and pull you in.... you feal it..... you freak out (until you get used to it)... and try to compinsate. This makes you "dance in the lane". You will see it on some roads worse than other. My car is all over the place on some roads, and better on others. You have to learn how it handles now. You changed the stock ride.

bill12690

iTrader: (4)

adjustable panhard would help but I wouldn't say thats your main issue. LCA's shouldn't affect it like that unless they're loose as hell,I would say double check all hardware and make sure everything is torqued down, including the struts and especially the swaybars. What size wheels do you have? I have c6 wheels (not OEM) and mine didn't require a spacer at all. Mine are 17x9.5 FWIW

UMI Sales

iTrader: (1)

Thanks for choosing UMI.

We've seen the wide wheel phenomenon many a time, unfortunately. Stock wheels back on and voila - instant nice car.

Do you have rear lower control arm relocation brackets?

And j agree that a front end alignment is a must.

gofastwclass

iTrader: (2)

I had a similar issue and the toe was really far out.

I'm lucky enough to have a small local shop that does alignments on hotrods, muscle cars and race cars along with new stuff. The guy did some things most don't: he asked me what it was doing, then he got in the car and drove it down their street BEFORE he put it on the rack. After the alignment, he drove the car again, put it back on the rack and got the wheel centered for me. One last drive confirmed he was happy with his work and away I went - and the car has never been better.

Now my car is completely predictable and fun under all situations.

97z2801ss

iTrader: (4)

Thanks for the quick responses

Yep I definitely know all the things associated with lowering and modding these cars, that's why this is so weird to me. I built my other 383 z28 from the ground up with the same parts, and never experienced anything like this. I know I should get an alignment ASAP, but if it were a bad alignment wouldn't it do it with any set of wheels? Btw my wheel info was posted in the first post.

I don't get why these wheels even need rear spacers in the first place... I can't find which company makes them, they are just slightly different than what oewheelsllc, motorsports, ect many companies sell. They are basically identical to the deep dish c6 from oewheelsllc, chrome, rivets, except the spokes run all the way out to the lip instead of stopping so the lip is pronounced. I'll post up some pics when I have time... But the offset on the rears is for some reason wayyyy too deep, they won't even sit on the hub without hitting multiple spots on the inner wheel big time. Nothing that can be hammered out or anything... Likes said ill get pics.

1 FMF

iTrader: (1)

when i had my 99 ss i had a complete reman'd rear axle put in the car under warranty. shop that did the work tightened the ever lovin' **** out of the stock rear LCA and PHB bolts to where there was no articulation of the rear and no suspension movement. When i went up my side street which was fairly rough it felt like the rear axle and rear tires would actually bounce off the ground over some of the bumps. your description reminds me of that. i ended up dropping the lca's and phb, greasing the sides of the bushings then hand tightening and problem solved.

97z2801ss

iTrader: (4)

Hey that's a good suggestion, I'll have to check that out ill get in there and make sure it's correct with the torque wrench.

therealcreeper

iTrader: (37)

also make sure your swaybar endlinks aren't cranked down like crazy or broken

97z2801ss

iTrader: (4)

I did tighten them by hand and I think pretty damn hard, I read on one of the suspension websites they should be tightened until the bushing smushes out to the size of the washer.

I have a lot of loosening and torque wrenching to do, it could be anything.. It was all tightened by hand.