Car all of the sudden bouncy?

[paul2241]

I have an 06 z4 3.0i with 35k miles on it. I have an issue where the ride has gotten bouncier than before. I noticed it when I left a restaurant the other night, on the way there I didn't feel any difference in ride quality. I have no clue as to what it could be, I didn't hit any pot holes on the way to the restaurant that would have caused such a sudden change. It's really noticeable between 35 and 55. I'm thinking I may have lost a wheel weight or something like that. There is a little bit of movement in the steering wheel, but I feel it more in the seat, so I'm thinking rear wheels. Any idea as to what this could be?
Thanks

[XMetal]

Are your sway bars intact?

[KevinC]

35k is about all the stock shocks are probably good for. Somewhere a while back (Bimmerfest maybe) somebody in the Z4 forum reported testing shocks at a similar mileage on a shock dyno, and they were toast. Not surprising, stockers are almost always crapola. Time for some Bilstein HD's. I'm pushing 40k miles and planning on upgrading soon.

[esqu1re]

Originally Posted by KevinC

35k is about all the stock shocks are probably good for. Somewhere a while back (Bimmerfest maybe) somebody in the Z4 forum reported testing shocks at a similar mileage on a shock dyno, and they were toast. Not surprising, stockers are almost always crapola. Time for some Bilstein HD's. I'm pushing 40k miles and planning on upgrading soon.

What? For real? That fast?

[johanness]

bye bye shocks

[paul2241]

how can I tell if the shocks are indeed the problem? What do they usually cost to replace?

[Rick F.]

Paul,

It sounds to be that, by "bouncy," you mean you're feeling a vibration such as an unbalanced wheel. A wheel that's out of balance usually results in a rapid vibration, very obvious through the steering wheel if it's a front wheel, generally more so through the seat of your pants if it's a rear wheel, as you mention.

Bad shocks, on the other hand, result in a "pogo-ing" feel when you drive over bumps, or, if they're really bad, when you come to an abrupt stop the car will shift up and down for a couple of moments. (Car springs, like any other spring, will tend to keep oscillating if there's nothing to damp them--like a working shock absorber. Z4 springs are stiff enough that they would tend to damp oscillations pretty quickly just from internal friction, but the motion would still be pretty noticeable.)

Anyway, if it feels more like a tire vibration, first make sure that your lug nuts are good and tight, and then get the tires balanced (looking for any tread damage in the process). You normally wouldn't develop a tire imbalance abruptly unless a wheel weight had come off, which isn't common.

Good luck, and let us know what the problem turns out to be.

Rick F.

[tman53]

I always thought that shocks go bad gradually, not all of a sudden. As posted above it sounds like your description is more of an out of balance wheel than a shock problem.

[bosstones]

Originally Posted by tman53

I always thought that shocks go bad gradually, not all of a sudden. As posted above it sounds like your description is more of an out of balance wheel than a shock problem.

Not if you blow one of your shocks out. Wouldn't the old "push down on a corner of the car and see how it settles out" apply here if the OP has a dead shock(s)?

[tman53]

If he did "blow out" one of his shocks he should easily be able to see that by removing the wheels.

[paul2241]

I did the push on the corner test, it goes down and rebounds without any extra bounces or drama.

[Hawkeye]

My shocks are on 50K miles and still going strong. Have not heard of anybodies shocks going bad on the Zed in 30K miles...