Suspension components? How long do they generally last? I know the obvious signs of completely broken shocks, but is it generally advisable to replace the shocks after a certain mileage? If I don't will at adversely effect the handling of my car? I have a 2006 e90 325i with sport package, with about 60k on the clock. What about struts/springs/other components?
Strut inserts and rear so-called "shock absorbers" are both spring dampers, and typically, long-lived. Springs stand a chance of lasting the life of the car, but I don't think it would be any surprise to see original springs on a 250k-mile (or more) BMW, at least for a 80's or 90's-era BMW. Possible that more current models might not have springs with similar durability, but I wouldn't know why. What may be more difficult to discern by the seat-of-the-pants with 'shocks' is when they're worn, but not completely blown. Which takes awhile, unless a shock fails prematurely - I'd think in most scenarios, one wouldn't contemplate having to replace shocks until 80k, or more, possibly even more than twice that. Handling shouldn't be negatively affected until shocks are shot, or substantially worn. What does tend to wear out long before shocks or springs are various suspension bushings, tie-rods, control arms, and so on. There's typically lots of rubber bushings integrated into BMW's, which eventually need replacing.
Thanks for the perspective. With shocks, I have heard everything from "don't replace your shocks until they fail the bounce test" to "replace them every 50-60k because by then they will have lost most of their useful dampening ability and your car won't corner/handle like it should". I suppose it would depend on the quality (or lack thereof) of the roads you drive on as well, correct? Is there any objective way to tell if a shock is "substantially worn but not blown"?
It depends... Mostly on what you expect for handling from your car... if you like to push it and expect it to handle sharply then replacing in the 60-80k range will keep your car's suspension performing up to spec. This assumes you also do frequent checks of the rest of the suspension components and replace them at the first sign of wear. If you plan to track or autocross your car it should be checked over carefully before you start a new year... your whole suspension and braking systems performing up to spec is a must. The bounce test is usually good if you like it to perform well but don't need it to perform exceptionally well. For this you are probably in the 100-140k range. If you have to travel over excessively rough roads often then the repair/replacement cycle will be shorter. There are a number of things that can accelerate suspension system wear, like out of round tiers, like out of balance tires, like bent or out of whack rims, like poor alignment, to name a few that are common. Get things checked at the first sign of any "issue" you notice and you will probably not have any serious wear problems. Failure to do anything about those issues is what usually causes premature failure of something and is usually quite preventable. I've seen it get pretty ugly when it gets ignored until something fails. (Here's something that will get me in trouble...) There is also a gender bias so keep a close eye on your girlfriend/wife's car as well as your own. Women just tend either not to notice it or continue to drive it without telling anyone there is a problem and the repair bill goes up considerably as a result. I can't tell you how many times I've seen a car limping up the break down lane of the highway with either a flat, or a steam or smoke trail. The first usually ruins the rim, the second usually causes serious damage to the engine. They simply should stop and call for road side assistance but they just have somewhere they need to be... and it turns out to be an expensive choice. (Boy did I get off on a tangent...) Chuck
