Expected Suspension Component Wear at over 100,000 miles E46

"M C" wrote

Well, everyone says that the bushings in the front control arms last only around 100K miles. I know that when I replaced them in my '91 E34 it did tighten things up.

However, the first thing to look at is your tires. I have the same size wheels and tires (Michelin Pilot MXM) on my '01 330xi, and am very aware that tire wear makes a significant difference for this car. I would try rotating your tires front to rear (both sides) and see if that feels better. If they are worn much beyond 1/2 tread depth, I would consider replacing them.

Floyd

I note what you say about the tyres. I tend to be a bit stingy with my tyres and if theres tread on them I'll keep them till they're illegal. Recently I did swap the rear tyres which were almost illegal for new ones (identical type Good Year F1 GSD3) and the handling became far worse! I now have the new tyres on the front and half worn ones (from the front) on the rear. This stopped the unpredictable handling and now it's reasonable again, but I still get the feeling that something is not right at the back. It would be expensive for me to change all the tyres at the same time, and would be silly if I still had no improvement. The way the car feels is that the rear is a bit jumpy / fidgety when the road surface is rough, seems to side step slightly. I'd expect it to be smoother, but maybe it is the tyres. The front seems mostly OK and I did have some bushes replaced at about 80,000 miles, may have been the control arm bushings.

Floyd, do you always swap all 4 tyres at the same time on your 330 ? Have you had any of the problems that I explained here ? What are your opinions on the MXM's ? Maybe I'll try a tyre like that next time round instead of the GoodYear's.

I'm also wondering how difficult it may be for me to inspect the suspension myself. Can someone advise what I should be doing when looking at suspension for problems and what to look out for.

Thanks

MC

Not sure what the rear suspension set-up is on the E46 but certainly on the E36 (my 325 Coupe) the trailing link bushes caused a weird sort of step out at the rear end, especially when cornering hard. If the E46 has then, they may not have gone completely yet (evident by a load knocking at the back when turning tight corners) but they may be on the brink and would benefit from being changed.

"M C" wrote

If I have a tire that gets some sort of separation or other failure while the set is relatively new (25% wear or less), I will usually replace it (or use the spare). However, I have had better results, especially wrt. handling/twitchiness issues when replacing all 4. IME, letting the tires wear to the markers is almost impossible (unless we're talking a Dodge Caravan, Isuzu Trooper or other mush-handling vehicle.) For instance, I hit a pothole and trashed a Pilot Alpine with about 15% wear and replaced it with a new one; no problems.

The MXM's have worn well, but are expensive. I will probably get PS2's when I replace the (which probably won't wear as well ;-> ) because for my summer set I'm only interested in performance. I've definitely decided that rotating tires on BMWs is a waste - the handling deteriorates and you save only a few thousands of miles before replacing the remaining front or rear set anyway.

My opinion on Goodyear is that they make good SUV tires that last forever. I had a set of original NCT's on my '77 Porsche 924 and they were great - back then. But I haven't been impressed with their build quality and high performance tires for over 15 years. Michelin IMO builds much better tires, especially snow and high performance tires. I've had Michelins on our '91 525i since replacing the OEM Contis (MXV4 and now HGT-V4) and they work great, as long as they have at least 25% tread left and aren't rotated.

IMO, it's very hard for *anyone* to really "look" or "inspect" a suspension and tell that it's bad. This is one of the most shot-gunned areas of car maintenance. About the only component that's easy to figure out if it's worn is shocks (the rock test.)

Floyd

Thanks for the replies, and what you included is useful. I used to always like Michelins myself but noticed that the GoodYears get good reviews on TireRack and were cheaper, so I tried them. I jacked the car up this evening on the suspect corner (rear drivers side) and there doesn't appear to be any play in the wheel and I cannot see any obvious bush wear. What Rick mentioned sounds plausable though and I'll get them checked out because my symptoms are just like what he suggested. Under hard cornering it kinda feels like there's some abnormal movement.

MC