VHHDT

Hi all

I have noticed that my wife's X5 4.8 has a better handling balance (you can balance it on the throttle) through corners or sweeping bends than my 540 M Sports which understeers quite significantly (doesn't feel like it will make the bend)..... not sure if this is speed related, but then yesterday I was going through a round-a-bout and an E53 X5 went past me on the outside at a pace my car could not hope to match (although he did cut the corner a fair bit)...

I understand that with an understeering style of set up you can get on the power a lot more (except that a 540 doesn't have that much to give) and carry a lot more speed..... but my car just does not seem to make that transition unless it is a low speed corner and I can punch it out by dropping down to second gear. A sweeping exit off the freeway means you kind of feel like you're hanging on....

So, my question is..... what are the opinions of all you M Sports owners out there.... would you say your car understeers? or not?

swajames

A couple of questions. Do you have all-season tires or performance tires, and have you looked in to either your alignment and/or your front suspension geometry? The E60 is indeed set up to understeer at the limit, but that limit, particularly with an M Sport, should be well beyond that you're describing here (and certainly beyond that of the X5). I'm wondering if your tires or suspension are perhaps to blame here?

vkhong

I agree with swajames. My 2004 530i Sport with ARS and AS feels neutral, with understeer only at limit. My tires are Bridgestone Potenza RE760 P245/40-R18 97W, non-runflat, non-staggered, 32 psi front and 39 psi rear. Wider rear tires (staggered) tend to induce understeer.

mhs525

Agree with above, no way should an X5 out corner an E60 just based on the physics of the weight and center of gravity.

Ways to optimize E60 handling and make it more neutral:

Dump run flats for good performance tires

Upgrade to lightweight forged wheels to reduce unsprung weight

Use similar tire pressure front and rear, a trick Dinan uses, BMW higher rear tire pressures contribute to the understeer at the limit, I run 34F 36R

Install a Quaife LSD and you can really rotate the car with the gas (huge improvement, the only way to make a non M car drive like one but damn expensive)

Yes these are all my mods and I really love the difference in the way the car drives. I can't change cars to a newer 550 because it would drive worse than the set up I have now.

Bteljuice

guys, I have the 124s: 245/40 R 18 and 275/35 R18.
What psi should i go for

I was going 30psi front and 34 psi rear during this summer.Is it too little? it seem you guys have more psi?
BTW, the road is filled with potholes if it makes a difference.

E60714

Could the AWD be giving the car a bit more traction? I realize it's got a higher center of gravity and weighs more, but it's possible maybe the X5 had performance tires and this guy didn't.

Rislar

There is deffo something up here, ive been in a few X5's and there is no way that should happen, they are way to top heavy to get round a corner with anyspeed !!!! i would check your geo and tyres or even your shocks!!

sdg1871

+1. Even with all seasons, an E60 (especially one with a sport suspension) should demolish any X5 in the twisties even if the X5 has summer performance tires (due to the X5's higher center of gravity and greater weight).

VHHDT

Hey thanks for the replies....

I have 19in 172's?? per my sig pic with run flats.... I run them at 38psi front and rear and have had my wheel alignment checked by the dealer. the brand of tyre is Continental Sport contact 2 245/35 R19 96Y Front and 265/30 R19 93Y rear...

Do the RFT have much of an affect on the handling? I might try reducing the front pressures and softening the ride slightly.....

ColdList

haha...Glad to hear that because I just ordered a Quaife 3.46 for my 550i 6M Sport. I've got the full Dinan Stage 3 tuning on mine as well and also waiting on new 20" HRE P43SCs to arrive. I really had very little understeer with my stock sport suspension (always riding on Michelin PS2s or Super Sports) but when I installed Dinan suspension with front and rear strut braces it improved quite a bit. HOWEVER, I would not be so quick to dismiss the cornering of the X5. Depends on the model. I just bought my wife an X5 4.8i with the sport setup and that thing is unreal. It has 20" 315s on the rear and 20" 275s on the front and that x drive is freaking phenomenal. I am not sure that I have ever driven a more nimble vehicle. Seriously, I am a "driver". I put my car through the paces pretty hard and I never expected to be so blown away by the X5 but I am. We have only had it a few days and I have found myself "borrowing" it quite a bit already. I am sure she and I will have a lot of fun taking our cars out side by side for a run when mine gets back home (in shop now getting the Hamann aero kit). Can't wait!