SL55/63/65/R230 AMG: Rear End Wobble- UPD Suspension kit SL5
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Joined: Aug 2015
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2003 SL55 AMG
Rear End Wobble- UPD Suspension kit SL5
I have a 2003 SL55 with 25k miles. It has been serviced 100% with zero problems until now.
I just had a shop install the UPD lowering suspension kit on my car with a new alignment and new rear tires. The front tires have about 4-5k miles and have some pretty uneven wear from lack of alignment and lowering the car. The car drove perfectly straight prior to the kit, I had this kit installed to stop the excessive rear tire wear. It appears the car is lowered around 1.5"-2" with lowering links. I have staggered 20" rims with 245/30/20 and 305/25/20's on the rear.
The problem is since I picked it up from the shop it’s almost like the back end dog tails back and forth just very slightly at highway speeds over 40 mph and wants to go in a different direction then the front end.
It’s kind of scary. Would this be the bushings? Is the kit installed correctly and is their a common fix? Would uneven front tire wear really move the car like this?
I just had a shop install the UPD lowering suspension kit on my car with a new alignment and new rear tires. The front tires have about 4-5k miles and have some pretty uneven wear from lack of alignment and lowering the car. The car drove perfectly straight prior to the kit, I had this kit installed to stop the excessive rear tire wear. It appears the car is lowered around 1.5"-2" with lowering links. I have staggered 20" rims with 245/30/20 and 305/25/20's on the rear.
The problem is since I picked it up from the shop it’s almost like the back end dog tails back and forth just very slightly at highway speeds over 40 mph and wants to go in a different direction then the front end.
It’s kind of scary. Would this be the bushings? Is the kit installed correctly and is their a common fix? Would uneven front tire wear really move the car like this?
Senior Member
Joined: Dec 2014
Posts: 258
Likes: 7
2003 SL55
I have a 2003 SL55 with 25k miles. It has been serviced 100% with zero problems until now.
I just had a shop install the UPD lowering suspension kit on my car with a new alignment and new rear tires. The front tires have about 4-5k miles and have some pretty uneven wear from lack of alignment and lowering the car. The car drove perfectly straight prior to the kit, I had this kit installed to stop the excessive rear tire wear. It appears the car is lowered around 1.5"-2" with lowering links. I have staggered 20" rims with 245/30/20 and 305/25/20's on the rear.
The problem is since I picked it up from the shop it’s almost like the back end dog tails back and forth just very slightly at highway speeds over 40 mph and wants to go in a different direction then the front end.
It’s kind of scary. Would this be the bushings? Is the kit installed correctly and is their a common fix? Would uneven front tire wear really move the car like this?
I just had a shop install the UPD lowering suspension kit on my car with a new alignment and new rear tires. The front tires have about 4-5k miles and have some pretty uneven wear from lack of alignment and lowering the car. The car drove perfectly straight prior to the kit, I had this kit installed to stop the excessive rear tire wear. It appears the car is lowered around 1.5"-2" with lowering links. I have staggered 20" rims with 245/30/20 and 305/25/20's on the rear.
The problem is since I picked it up from the shop it’s almost like the back end dog tails back and forth just very slightly at highway speeds over 40 mph and wants to go in a different direction then the front end.
It’s kind of scary. Would this be the bushings? Is the kit installed correctly and is their a common fix? Would uneven front tire wear really move the car like this?
If not, check your alignment. Its likely your toe settings arent where they need to be if you have instability at high speed.
Last edited by m-svt-amg; Apr 10, 2016 at 04:47 PM.
Junior Member
Joined: Mar 2015
Posts: 67
Likes: 3
From: Texas
SL600
OK...I don't feel like a moron now.
As many know I did an ABC delete and installed coilover on all four wheels. I switched from 20" back to 18"'s to get better ride quality and feel the same effect. It is almost like the car feels like it hits a rut in the road and moves the rear end around. The car corners like it is on rails, but the slightest imperfection in the road makes the rear squirrely.
I thought it was the coilovers and thought I would have to live with it, but now I am not so sure.
P.S. It seemed to get worse when I added spacers to the front wheel to help with clearance issues with the new sway bar.
As many know I did an ABC delete and installed coilover on all four wheels. I switched from 20" back to 18"'s to get better ride quality and feel the same effect. It is almost like the car feels like it hits a rut in the road and moves the rear end around. The car corners like it is on rails, but the slightest imperfection in the road makes the rear squirrely.
I thought it was the coilovers and thought I would have to live with it, but now I am not so sure.
P.S. It seemed to get worse when I added spacers to the front wheel to help with clearance issues with the new sway bar.
Senior Member
Joined: Dec 2014
Posts: 258
Likes: 7
2003 SL55
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Junior Member
Joined: Mar 2015
Posts: 67
Likes: 3
From: Texas
SL600
Apologies for not following up sooner to anyone that had this problem, but mine surfaced after I switched from 21" wheels back to stock 18's. I had an alignment done, so I didn't think that was the issue, but I after several months of this weird rear-end wobble I took it to a more competent suspension shop. They re-aligned and the problem went away.
Just to be clear, my car no longer has an ABC, so I am running a rear sway-bar which could have exacerbated things.
Just to be clear, my car no longer has an ABC, so I am running a rear sway-bar which could have exacerbated things.
