Saggy Butt? Premature Shock or Spring Wear Problem?

[goofiefoot]

I figured I "officially" pose this question where it belongs.

Got the style 197s installed today with new Kumhos. Now, I know they have a lower offset (ET37), and the figure I heard thrown around was they would stick out 13mm further than stock. No clue if that's true, but they certainly are closer to the edge. I was pretty confident they would fit my stock suspension without and rubbing, after researching here and other sites. However, they do rub on dips and road humps.

Looking at my car from a distance, I've noticed my rear fits nicely over the wheels, but does have a slightly "lowered" look. I chalked this up to the ZHP suspension, but now I'm not so sure. I'm fairly confident the previous owner did not abuse this car, but is 57k miles too early for a suspension to sag? If it truly is sagging, do I blame the shocks or the springs? What would be the best solution to fix?

I'd love some thoughts. I'd rather not change out the wheels now that I have the tires on them, but I don't want to tear up my car.

Here's the latest photo for reference (along with my signature):

[Hornung418]

Copied from the other thread:

Jason, That looks awesome! You should want to roll your fenders. The offset is 37 in the rear and 34 in the front. That should clear up any rubbing issues. The wheels are identical to the 135s except for the offset so there is no change in ride height, just a more flush wheel.

I do not detect any form of "Moar Lowar" in your pics. I think it's the placebo-effect in action.

[goofiefoot]

Copied from the other thread:

Jason, That looks awesome! You should want to roll your fenders. The offset is 37 in the rear and 34 in the front. That should clear up any rubbing issues. The wheels are identical to the 135s except for the offset so there is no change in ride height, just a more flush wheel.

I do not detect any form of "Moar Lowar" in your pics. I think it's the placebo-effect in action.

Crap, I was pretty certain these would fit without any modifications, including fender rolling. Not really what I was hoping to hear.

[Hornung418]

Dude, fender rolling is a breeze. Just get a roller from the auto parts store and a lady friend's hairdryer and you're set. The only thing that you have to do is scrape out the gunk in the lip or it wont' roll flush. Dane, Kristen (kpro), Eli (mimalmo) and David (mtnman) have all done it, so there is a small support group should you find difficulty in the procedure

[goofiefoot]

Honestly, I'd never really seen or explored the fender-rolling process, but I just watched a couple of youtube videos. It's not as bad a process as I was imagining. I'd certainly want some better instruction than what I saw before I'd even think of attempting this.

I guess I'm still not convinced that my rear suspension isn't simply sitting lower than it should. Since we're all driving 6+ year-old cars, it would be hard to determine what the stock rear ride height should be by simply measuring. Any ideas?

[danewilson77]

I have ZHP suspension specs somewhere on the site. measure from top of wheel well to center of rim.

HTC Thunderbolt+TT

[Oli77]

It is measurable and BMW has these numbers in the Bentley I think.

There is a thread too.

Looking....

[Mtnman]

To determine ride height just measure from center of the bmw emblem on the cap, to the fender. I posted my stock numbers somewhere here. Ill have to look for it.......

Rolling is a breeze with the proper tool. Kpro brought one down to danes for the first meet. I did mine there. Just make sure to reach up in the "channel" that exists, and scrape out any dirt, etc, that may have lodged up there. The fender is like a u. You are just going to flatten it to minimize the distance between the two verticle sides of said u shape. Mine had dirt and crap in it. Whole process took an hour. And I went reaaaaaalllly slowly. I think I was jeered at for how slowly I went if I recall...lol.

Sent from my DROID3 using Tapatalk

[goofiefoot]

I'd be curious to see that stock height number. Thanks!

For sake of time, I'll check around for a local shop to roll them. I'm not sure how much damage each rub will do to my new tires and my fenders, so I don't want to delay too long. My wife's gonna be pissed!

[MrMaico]

Nice looking wheels Jason! At 57,000 I wouldn't expect any sag in the springs, unless you have a broken coil. I think Dane had one so he could tell you better what to look for on your rear springs. Worn shocks won't have any effect on static ride height. Can you see where it's rubbing?

Barry