thrust arms again.............

[MBXB]

Which bushings did you decide to install, Tim?

[632 Regal]

after you get them in.

[tim s]

$89.95

the best price i found.
tim s.

[rockyfeller]

I also have thrust arms that lasted only 20,000 miles. The stealer did them the 1st time for a pretty penny. When I took it last week to another shop he told me they were shot AGAIN! He's right because I didn't realize how badly the car was riding till he changed them and now what a difference! I didn't want to chance anything so I changed the whole arm with Lemforders. I still have a slight shimmy, but I'm attributing that to unbalanced worn tires. Shouldn't those bushings last at least 50,000 miles? What type of driving behaviour contributes to premature wear of the bushings? What kind of forces do the arms/bushings counteract? I'm driving all paranoid now trying to make sure I don't do something to wear them out quick again. With so many of us having this classic problem this has to be the result of a bad design fault on the part of BMW. They should design some kind of updated super-heavy duty design for this part.

[Mobius]

$89.95

the best price i found.
tim s.

I don't know if I'd use a poly bushing in this application for daily-driver use. Aside from the noise and harshness factor, there's a lot of design in the OE bushing that apparently takes into account the sort of forces placed on this bushing. This is why they have to be oriented specifically when pressed into the arm.

Also, by going to a hard bushing like this, you're putting a lot more force on the components related to the bushing. My roomate drives a 300ZX and he pointed this out to me a while ago. The 'tension rod' that they refer to there (which was mounted to that bracket with a non-OE poly bushing - before it fatigued and ripped apart) - serves essentially the same purpose as the thrust arm in our application - it principally handles fore/aft thrust.

I'm not saying that's going to happen - just to keep such things in mind.

[tim s]

i remember nissans as being very thin.
tim s.

[Mobius]

My point wasn't that you're going to do that to your thrust arm mounts, my point is that you're putting a LOT more stress on these mounts, and a lot more stress on the suspension in general by taking away the flex that BMW designed into that bushing. This is something you should consider and be aware of when switching to polyurethane bushings.

And there is nothing at all thin about that bracket - the 300ZX suspension is even more tank-like than my BMW's, and I say that without any shame. I've seen both up close and personal. The 300ZX isn't exactly a typical japanese econobox.

[Bill R.]

has the original bushings and thrust arms at 135,000 miles. I have stock size tires and wheels, stock front springs, stock struts and no shimmy. When you change the wheel size and go to lower profile tires, all the sudden the tires don't absorb as much of the day to day punishment from the road, instead the larger wheels and lower profile tires transmit more of this pounding to the bushings, also add lowering springs and stiffer struts such as the bilstein, all of these items compound the amount of force transmitted to this bushing, aggressive driving with hard stops/starts also transmits a greater load to the bushings.. now each component in line on the stock suspension absorbs a certain amount of shock load that it gets from the road, Each of the (improvements?) that you make to the suspension/wheel/tires/springs transmits more of this shock load to the next component in line... End result
you'll kill bushings/balljoints/wheelbearings etc. quicker. Its just the price you pay.

My point wasn't that you're going to do that to your thrust arm mounts, my point is that you're putting a LOT more stress on these mounts, and a lot more stress on the suspension in general by taking away the flex that BMW designed into that bushing. This is something you should consider and be aware of when switching to polyurethane bushings.

And there is nothing at all thin about that bracket - the 300ZX suspension is even more tank-like than my BMW's, and I say that without any shame. I've seen both up close and personal. The 300ZX isn't exactly a typical japanese econobox.

[tim s]

i called dinan but they did not know much about there bushing. i am waiting for my local dinan dealer to call me back with info on the dinan bushing.
bmp told me the the urethane bushing is going to be noisier & will need grease applied to keep it from squeeking.
thanks for your input!
it is very appreciated!
i want to make an informed decision & this forum has helped greatly.
tim s.

[tim s]

these are listed as heavy duty.
any body ever use these?
they do not appear to have the plastic inserts.

thanks
tim s.