rear end swap now my ride is bouncy

[ss_shaun]

Ok I've swapped in a 9 inch rear in my chevelle finally got it on the road yesterday and took it for a test drive and it was great BUT my rear is so bouncy now. Its almost like I have no shocks in the rear and i am riding on just the springs. I have the 2 inch drop springs in the rear with the hotchkis shocks to match. With my old rear it drove smooth with no issues. I can't find the specs on the hotchkis rear shocks but i am not sure what else to do next. Any suggestions?

[andrewb70]

Ok I've swapped in a 9 inch rear in my chevelle finally got it on the road yesterday and took it for a test drive and it was great BUT my rear is so bouncy now. Its almost like I have no shocks in the rear and i am riding on just the springs. I have the 2 inch drop springs in the rear with the hotchkis shocks to match. With my old rear it drove smooth with no issues. I can't find the specs on the hotchkis rear shocks but i am not sure what else to do next. Any suggestions?

Did you just swap rear ends, or did you add the springs and shocks at the same time?

Andrew

[dhutton]

Lowering springs generally have a higher spring rate. ridetech has dual rate springs for your application which should give a better ride. So does UMI if I remember right.

Don

[ss_shaun]

so after lots of playing around today I said let me go pick up some stock style shocks I picked up some gabriel shocks for 50 bucks took them home. I took my belstien (spelling) and what i did was compressed the shocks all the way down then i compressed my stock shock and it was a HUGE difference. So i put the stock style shocks in took her for a test drive and its like how it was before i did the rear swap. So what I am thinking is this. My old 12 bolt had that "lift bar" added to my control arm and maybe that give it a little more distance of travel for the rear shock. Now that i have all UMI in my rear. (upper and lower control arms and sway bar) it is smooth as butter!! so the whole problem was the shocks!

[dhutton]

I had Bilstein shocks on my GTO and I thought the ride was great.

Don

[ss_shaun]

Yeah it was for me too. After the rear swap it was like I didn't have shocks

[UMI Tech]

Are the Hotchkis shocks the newer style Fox ones?

Is the axle significantly heavier than stock?

And, are the shock mounts in a significantly different place?

ramey

[ss_shaun]

Are the Hotchkis shocks the newer style Fox ones? no clue I went to summit ordered the ones to match the UMI springs the tech said they would be good. I had them on the 12 bolt no issues

Is the axle significantly heavier than stock? I am going to say about the same I was able to pick up the 12 bolt by myself and i can pick up the 9 inch by myself

And, are the shock mounts in a significantly different place? Its in the same mounting hole.

[UMI Tech]

Hmm. In general the Hotchkis shocks can damp properly with our springs and a 9". I wonder if the arm angles are different?

[ss_shaun]

I am going to say that is the problem. I had lift brackets on the 12bolt

[UMI Tech]

I am going to say that is the problem. I had lift brackets on the 12bolt

We just optimized some stuff on our LeMans with respect to arm angles (for racing) and miraculously the ride changed significantly with the exact same shocks, springs, and component weight.