Which additional damper used in rear shock?
 

Hi all here! I need your help now. Recently I feel the rear shocks very stiff, so that makes my rear passengers feel really bouncing. I guess that it might be the additional dampers in the rear shocks have gone bad. I checked in realoem.com and found that there were two types of additional dampers used in the rear shock, in which one is 80cm and the other one is 90cm. Just wonder which type I should use if I am going to renew the additional dampers for my car.

Besides, do you have any other idea why my rear shocks run so stiff? Is there anything else gone wrong?

Thanks for help and your ideas!

No one can help here? I attach the diagram from realoem.com for you guys' easy reference.

http://bmwfans.info/parts-catalog/E5..._spring_strut/

It is the item number 5 in the diagram. Thanks for help!

The 80mm are for self leveling suspensions while the 90mm are for both standard and Sports models. Are yours the original shocks?

Yes. Mine are original shocks. Do you think jumpy ride is caused by bad dampers or maybe something else? I checked in the realoem.com and it showed that 80mm was for 2-axle leveling suspension with sports setting, so mine are 80mm. Thanks for help.

The spongy dampers shouldn't have any ill effect on the shocks. I think the shocks are worn and I'd recommend replacing them.

I replaced mine myself last summer and wasn't all that difficult of a task.

Agreed the 80 or 90mm "additional shock absorber" is that old schoolers call a bump stop for when/if you bottom out the shock travel.

Changing the rear shocks will make an improvement in your ride overall. Agreed it is not a hard task.

If you have air ride or self leveling suspension then another item to check is the calibration of the ride height. There are a lot of posts on here about ride height calibration impacting ride quality.

Thanks for reply! The ride height of my car is correct, mine is 4.8is wiht 2 axle air shocks. So you guys recommend replacing the whole rear shocks instead of replacing the dampers only. Do I understand correct?

by the way, my x5 has only less than 90,000 kms (56,250 miles) of mileage, do you think the shocks is gone at this mileage?

depends on the driving habits, road conditions, etc.

50k miles does seem a bit early. I would expect anywhere from 80k-100k miles to start having suspension issues.

I don't understand what you see are dampers vs. shocks (depending if you use the Queen's English or not). If you find the car a bit "hoppy" in the back - replace the rear shock absorbers (I did and it resolved the problem - my car has rear air suspension as well).

Does it seem to be less "bad" when you fill the gas tank up or have more cargo (weight-wise) in the back of the car?

You don't mention mileage of the car and I don't know about road quality in the Hong Kong area. The OEM shock is Bilstein low pressure gas (black body, B4 setting). I replaced with the B6 (yellow body) sport version - no regrets.

If you are in the city and as you have VERY low profile tyres (20") you may be happier with the B4 version.