jaxen112

I picked up an 05 545i sport (manual) a few weeks back, after the initial break in I started getting on it at my ususal driving spots to get a feel for it. Now I'm hoping it has something to do with the run flat tires or perhaps even the fact that the back wheels are staggered, but this car has LOADS of understeer. right at the limit, the car feels (and if I dont let off the gas as if its going to simply wash out up front and send me right into the woods! I know this can be corrected with oversteer easily, but I have a 35k lincoln ls that handles at this limit better then this car.

kind of sucks.

JayJay

Either you are not driving it right or something is wrong. Take it in to be checked. Ive pushed my 525 to the raggedy edge and its never understeered.

JayEll

i changed from RF to Pirelli because i found the RF to be too slippery.
unfortunately the weather hasn't let me test the Pirellis yet.

not that i was pushing it to the limit though ... find that hard on public roads.

jaxen112

not to blow my own horn or anything, but I've never driven with anyone that I feel can control a car better then I can, sure its possible I dont have a complete feel for the car just yet, but understeer is clear as day. I thought to have it checked as I bought it from a dealer with 3k miles already on, supposedy was a "dealer car" for its first few thousand miles which is fine by me as long as it wasnt wrecked and repaired etc..

the weather is cold now and I agree the tires up front feel a bit slippy at times (even if I feel they should have already warmed) have a friend who bought a 530 yesterday so I might take his out for a comparison being as they are the same chassis *minus run flats

thanks for the replies gents

BetterMakeWay

Might be the tires? What tires do you have? Or it might be smth more....anyway do the comparison and then tell us what you felt.
Mine doesn't understeer almost doesn't at all. I love the precise direction and direction feel and when i drive hard i pinpoint exactly where i want to go and how with sharp precision even though it's a car that weighs 1700km+. Also there is VERY VERY little understeer wich is actually good. That's the right way. But it is almost undetectable, and if it is it's cured with a slight lift off or by pushing the tail out. In the last case i find also unbealiveable responsible and even then i can accurate point the way to go, although there is almost always a hard sense of fish-tailing once i lift off. The lack of lsd is there, and by God the 5er needs that especially with that much torque.

1600

BMWs traditionally have a bit of understeer, however, with the active steering on the 545i sport, I find it remarkably precise and unerringly controllable. It seems reasonable to assume something is wrong with your vehicle that needs immediate attention. Did you purchase the vehicle from BMW? You said it was driven several thousand miles before you purchased it. Do you have a vehicle history report? I wish you good luck resolving this rather serious issue and look forward to hearing about your conclusions.















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jaxen112

I love the active steering, actually am convinced that all manufactuers will go the same route in time, but am certain its not coming into play here. the Tires are factory default, honeslty havent even checked the brand yet but know they are run-flat.

Ray Hull

Welcome. You don't say where you are and how cold it is, but there are very definite temperature traction disparities with the Dunlap runflats. Indeed, BMW literture states clearly that these are not winter tires. While we all assume that means no-snow-go (and how!), others have reported less adhesion in freezing temps. While I can't say that I have pushed mine to the limit (with RFs or currently mounted snows), I will say that, coming from the E39 predecessor (540iS 6 spd) that this cars STEERS altogether differently.

First, you have to get used to the Active Steering (after 4 months, I'm still working on over-correcting in parking maneuvers). But beyond that, I find this car has very llittle on-center feel or control, and I am talking both tire styles. I think that sense of staying on track at center is the result of negative camber, but I'm not sure (you probabaly know more than I; it's been long time since I've read anything on such aligment issues) but the bottom line is that the design and the alignment, as well as the tires, all play a crucial role in this road feel. Others report that the tires tramline, and that the car is buffeted by and wanders seriously in sidewinds.

Without wading into deeper techincal waters (where I need a life jacket), I'd suggest that you consider the tires and the temps and not make any final decisions until you've played in 50+ degree weather and grown a bit more accustomed to the AS difference. If nothing else, you'll discover new ride comfort too.

Cheers,
Ray Hull

freed0m

I experienced the understeer at ~40 MPH last month, took my E60 to the dealers (twice), they replaced the steering rack the second time. Things are fine for now... So take your E60 to the dealer and let them take a look at it. I'll look for my service document later on today to see if there are additional information.

needforspeed

Oh to be able to be dissapointed by a 545i

I don't doubt your sh*t hot driving ability, but no powerful rear wheel drive car should scare anyone with understeer.

Tail goes out all of the time, but understeer - not really.

If yours is understeering this badly, then there is something wrong with it.