urethane bushings

[christophbmw]

im looking at installing some rear subframe mounts, and some trailing arm bushings. does anyone know much about urethane? i dont want it to be to hard on the chassis because its an 85. also what is the ride like? im running on H&R sports with bilistien shocks. what about sway bar busings? does urethane sway bar bushings make a big difference? thnks.

[nando]

uhh, it's made of polyurethane instead of rubber, and uhh it's kinda plasticy and stuff :P

seriously though, your chassis will be fine. urethane isn't *that* hard, I've driven 12,000 miles so far on mine and I only vibrated one part of my car loose. ;)

I still have my old stock rubber bushings, of course the rest of my rubber was still in decent shape so I'm not too worried, they'll be replaced whenever I get a new swaybar anyway.

[decay]

Re: urethane bushings

im looking at installing some rear subframe mounts, and some trailing arm bushings. does anyone know much about urethane? i dont want it to be to hard on the chassis because its an 85. also what is the ride like? im running on H&R sports with bilistien shocks. what about sway bar busings? does urethane sway bar bushings make a big difference? thnks.

i have no experience with them... yet... but what i heard from those in the RWD nissan crowd who installed them is that one can expect a BIG decrease in ride quality.

[nando]

I don't think so, my ride quality isn't any worse because of the bushings, that barely made any difference. most of mine is from the shocks :P

[Beej '86 325es]

I look at urethane as being more of a performance addition, rather than something used for reliability and longetivity. Mainly because of the fact that you're going to have to grease them again before you would have to replace a rubber bushing. But they are much easier to install because you do not need a press. Also, you may have some squeeking or creeking occasionally on break in. I still have a creeking noise at very low speeds going over bumps with my subframe bushings.

[M3 Ryan]

My M3 is all urathane... and its squeaks a LOT and has additional vibrations. if I did it again, I wouldn't do the subframe bushings in urathane as I think that adds a lot of the noice/vibes to the rear-end...

[Bryson]

I have no extra noise or vibrations in the rear end with my urethane subframe bushings, no squeaking either, I have the IE ones paired with factory rubber trailing arm bushings... that might be everybody's problem

[Ryan Stewart]

I have no extra noise or vibrations in the rear end with my urethane subframe bushings, no squeaking either, I have the IE ones paired with factory rubber trailing arm bushings... that might be everybody's problem

Ditto, quiet as heck. I replaced the subframe mounts with urethane and did the stock rubber ones for the trailing arms because I had heard that some urethane ones would squeak if they werent greased regualrly. The subframe feels very solid and the bushigns were easy to put in.

[Beej '86 325es]

I have no extra noise or vibrations in the rear end with my urethane subframe bushings, no squeaking either, I have the IE ones paired with factory rubber trailing arm bushings... that might be everybody's problem

I have powerflex subframe bushings and factory rubber TA bushings. Just creeks over bumps when going very very slowly. Otherwise, not really any squeeking.

[Bryson]

also, mine aren't greased, jut thought i'd add that

[SlammedE30]

All urethane out back, the car squeaks, but it did that before cause of the sway bar bushings. I'm over it :P
-Ted

[65Matt]

A little trivia for you guys - Rubber bushings are designed to twist. That's why they are silent, and the control arm bushings have to be installed with a temporary lube, like soap. Once the soap dries, the rubber 'sticks' to both parts.

Urethane is different in that it is not designed to twist. That's why you install them with grease. Over time, the grease gets squeezed out and they start squeeking.

[Bryson]

:) that's the reason I only did subframe bushings, they don't need to twist.. I might pick up a diff mount in urethane also some time, anybody have one of those?

[nando]

yeah I have one, skip the diff mount. It's a PITA to put in and it's not much stiffer than a new factory peice, plus it doesn't fit all that well. Spend the money on a new cover (M coupe) intstead, it comes with a new bushing and you can put it on with hand tools (you need a press for the diff bushing, which requires you to remove the cover anyway)..