I had a set of X5 thrust arm bushings installed in my 00 m5 yesterday. My first set of oe bushings failed at 45k, second set started getting soft at 65k (i'm now at 73k, the latest bushings have not failed completely, but there is a significant amount of movement in the suspension from their fatigue).
Track time, with big tires on the front, especially R compound tires is hard on the bushings. I was hesitant to go with polyurethane, due to past use (admittenly in other cars, probably older technology too), squeeks and sometimes failure with hard use. I had heard some internet rumors that X5 bushings would work, and were significantly "heavier duty." Makes sense, the X5 is a heavy truck, with huge wheels. I went to my parts dept to check them out, side by side with the M5 bushings (which incidentally are the same as e38 7 series bushings). I had my parts guy pull a set of x5 4.8is bushings (turns out they all have the same p/n).
I have attatched a couple of pics below. First thing is the housing. It's steel rather than aluminum. The metal part in the center, where it mounts, is much larger on the X5 part than the x5 part, easily 50% more metal at it's central mounting point. Also, in the upper part of the photo, the area where the metal mounts to the rubber, the x5 part has a lot more contact area. I wish i had my camera to photograph the m5 part, but there is easily 2-3x the contact area, where the metal and rubber are joined. The rubber itself felt harder with the x5 bush too. Physically, the bushings are the same size.
The install. My local independent shop (M service, in walnut creek, ca.) did the install. No issues, simple remove and reinstall. The shop is staffed by fellow bmw cca instructors, they were interested in the project, since the bushing did look "beefier" than the oe m5 part. Proof will be told over time, but they thought this might be a good upgrade for anyone who tracks thier e39, or has had multiple failures. I was replacing worn out parts, so it's hard to say how much better the car feels. Certainly there is some found precision back in the steering. Car is more stable under braking, and doesn't dart around on bumpier roads. No loss of smoothness, no increased noise or vibration. So far i'm pleased. The car had felt rather 'sloppy' over the past, say 6 months. I figured the recently replaced thrust arm bushings were too new, but there was quite a bit of play in my old ones, mostly on the drivers side. The front end feels much better, subjective i know, but that's all i can offer! I can see no downside to using these as a routine replacement when the OE bushings fail, especially those of you running larger tires on the front, or with heavier wheels.
Mike
Track time, with big tires on the front, especially R compound tires is hard on the bushings. I was hesitant to go with polyurethane, due to past use (admittenly in other cars, probably older technology too), squeeks and sometimes failure with hard use. I had heard some internet rumors that X5 bushings would work, and were significantly "heavier duty." Makes sense, the X5 is a heavy truck, with huge wheels. I went to my parts dept to check them out, side by side with the M5 bushings (which incidentally are the same as e38 7 series bushings). I had my parts guy pull a set of x5 4.8is bushings (turns out they all have the same p/n).
I have attatched a couple of pics below. First thing is the housing. It's steel rather than aluminum. The metal part in the center, where it mounts, is much larger on the X5 part than the x5 part, easily 50% more metal at it's central mounting point. Also, in the upper part of the photo, the area where the metal mounts to the rubber, the x5 part has a lot more contact area. I wish i had my camera to photograph the m5 part, but there is easily 2-3x the contact area, where the metal and rubber are joined. The rubber itself felt harder with the x5 bush too. Physically, the bushings are the same size.
The install. My local independent shop (M service, in walnut creek, ca.) did the install. No issues, simple remove and reinstall. The shop is staffed by fellow bmw cca instructors, they were interested in the project, since the bushing did look "beefier" than the oe m5 part. Proof will be told over time, but they thought this might be a good upgrade for anyone who tracks thier e39, or has had multiple failures. I was replacing worn out parts, so it's hard to say how much better the car feels. Certainly there is some found precision back in the steering. Car is more stable under braking, and doesn't dart around on bumpier roads. No loss of smoothness, no increased noise or vibration. So far i'm pleased. The car had felt rather 'sloppy' over the past, say 6 months. I figured the recently replaced thrust arm bushings were too new, but there was quite a bit of play in my old ones, mostly on the drivers side. The front end feels much better, subjective i know, but that's all i can offer! I can see no downside to using these as a routine replacement when the OE bushings fail, especially those of you running larger tires on the front, or with heavier wheels.
Mike