[doughboy]

Found an old thread on this is the old general section, no answers though, but wanted to raise it in the new tech section.

My new E91 335i m sport handles like a dog and understeers like mad. One's I test drove seemd very similar to my 330i E90 (short drives of course)

I know the tourers are slightly softer sprung and damped than the saloons (i think) and the rear ARB is 1mm less than the equivalent E90, so a possibly a bit more rear grip.

The body roll is pronouced, and the understeer under medium acceleration is frankly scary.

Travelling from Leek to Macclesfield on Friday (sunny and dry) coming round a left hand second gear bend, bit of gas on the exit and it just crossed the white line heading for the far curb, 1/4 a turn more lock did very little, cars coming the other way, off the gas then sudden grip and lurch back into my own lane....

Yesterday on a A road in between Stafford and Newport I've known for 20 years, sweeping left hander about 80 mph, I really felt like I had no control of the car at all, felt like it was floating round the bend, a mix of undulating body roll and what felt like varying front/rear grip, i felt sick after that. Looking in the eyes of drivers flashing by the other way thinking I (and them) could die here.....

My E90 was a gem compared to this, sharp turn in loads of front grip and the car felt like it turned under your owm backside.

I thought it was bad when brand new, but now after 500 miles its no better.

BUT - I did clobber a speed bump realy hard after 250 miles, but nothing seemed to change after that?

Any other ideas?

[Beaky]

No idea on the technical side but have you checked the tyre pressures - wonder if being out within the tolerances of the computer may make a difference??

[Serjames]

you running bridgestone rfts ?

I've felt a MAJOR difference going from the FRT's which were CRASHY but Felt solid on the road to TOne's winter tyres which with major block movement make the car feel like it's floating... with LOADS of body rolll.. I run stiff Hartge Anti rolls too...

Fortunatley it's not my main car, I don't think in the dry I could keep it :/

SJ

ROLL ON NEW WHEELS AND TYRES... pretty please !

[doughboy]

I'm on Michelin 18" staggered PS2 RFTs (same as previous E90 330i)

Pressures have been as rating label (2.2 / 2.8 bar)

Rear 2.8 seems high IMO, so this morning i've dropped it to 2.4 which is what my 330i ran at.

I'll see how that feels on the way home.

It's booked in on Friday for a KDS alignment too.

[NFS]

Originally Posted by doughboy

The body roll is pronouced, and the understeer under medium acceleration is frankly scary.

This stands out to me. There is very little body roll on my e90 and I would expect the same on a touring. I don't see that this could be due to tyres or alignment.

I'd ask the dealer to check the suspension. I've seen photo's of a car where the dealer had left the transit blocks in after delivery. Stranger things have happened.

[Carrera RSR]

Mine goes round corners fine but then it doesn't have the might of a 335. Never had understeer. Feels the same as E90's I've driven. Rear just a touch heavier. Yours doesn't sound right.

[Serjames]

hmm, suspect higher pressures might be the answer not the problem... ?

The suspension on these is set to take accound of the VERY stiff side wall on the RFT's take that out and it might mess them up unless you use the right pressures ?

Tone's the man here, he's messed with most tyres and most pressures...

[dxb335d]

LOL aint he just.

[Cafe.Racer]

Originally Posted by carrerarsr

Mine goes round corners fine but then it doesn't have the might of a 335. Never had understeer. Feels the same as E90's I've driven. Rear just a touch heavier. Yours doesn't sound right.

Have to agree - mine's fine, too.

[Parbox]

if I am not in Sport or Manual mode I find I understeer all the time. In these 2 modes I can keep the revs up to bring the back round to where I want it.

See if you get the same problems in manual.

[doughboy]

Originally Posted by NFS

This stands out to me. There is very little body roll on my e90 and I would expect the same on a touring. I don't see that this could be due to tyres or alignment.

Parbox - i've a 6MT, no auto buddy!

Update:

When I say pronounced, i mean for a E9x with m sport suspension, not in the normal sense.

I see 2 issues:

1. Body roll. The E91 has slightly softer springing all round and a higher c of g at the rear. It also has 1mm thinner ARB (acc to realoem.com) on the rear than E90, E92 and E93 which will exacerbate the issue IMO. A softer rear ARB (or more roll due to other factors) will effectively increase rear grip and thus increase understeer.

2. Vague, unstable steering at speed. This may be the alignment following my speed bump incident, have to see what the KDS shows.

Re item 1, the roll does feel like it is led by the rear, imagine a car with a piano strapped to the roof rack (right at the back) that is the sensation (not quite as drastic as that though)

Reducing the rear pressures to 2.4bar from 2.8 did have a very noticable effect. The front/rear grip at low to medium speed now feels more balanced, but more importantly it feels constant instead of varying. The rear did have a tendency to jump out of line with a 'bang' when crossing a manhole or banding during cornering, now that is gone and matches the more linear front end grip. (more like what i expect the PS2's to be).

Also, this will please the wife, the sun visors now don't vibrate when down which they did from new!! (she'll be able to use the vanity mirror!)

Too much traffic last night for trying any higher speed antics...

Maybe it is still due to friction / stiction in the bushes / struts etc and it will loosen up (the engine has transformed over the last 200 miles)?

[DaveC]

Not sure the about the softer springing bit, not something I've seen mentioned before.

Anyway, my E91 SE handles just fine, not a lot of body roll (slightly more since it changed to non RFTs) and is fairly neutral. Yours does not sound right.

[doughboy]

I've read before that the tourers are marginally softer sprung and damped.

This shows where the front bumper scrapes on the ground when coming down the back side of local speed humps where my e90 330i would have been fine.

Looking at realoem.com the tourer has different m sport dampers and bump stops all round compared to the E90. Spring rates are not shown, but for sure would be made to suit damping rates...

Time to book in with Ant for some ARBs IMO...

[doughboy]

Originally Posted by Serjames

hmm, suspect higher pressures might be the answer not the problem... ?

The suspension on these is set to take accound of the VERY stiff side wall on the RFT's take that out and it might mess them up unless you use the right pressures ?

Tone's the man here, he's messed with most tyres and most pressures...

The side walls are still stiff with or without any air at all (stiff enough to hold the car up when flat of course). More pressure just seems to add to the bouncey-ness of RFTs.

The saloons give different rear pressures for lightly or heavily loaded use.

My E91 only gives one rear pressure, maybe they assume you will always be loaded up with a tourer? Not the case for me at all.

Its much better with 2.4 on the rear.

[DaveC]

Originally Posted by doughboy

This shows where the front bumper scrapes on the ground when coming down the back side of local speed humps where my e90 330i would have been fine.

Which, of course, mine doesnt do.

Maybe you should make sure you dont have a problem before lumping out for roll bars, my touring handles just fine.

[doughboy]

Originally Posted by DaveC

Which, of course, mine doesnt do.

Maybe you should make sure you dont have a problem before lumping out for roll bars, my touring handles just fine.

.....Just fine in your opinion of course ;-)

The KDS and underbody checkover should verify any alignment / damage issues. But the body roll is what it is and spring / damping rates / bump stops are what they are. The 335i is 85kg heavier than 330i, so it will have more momentum in its movement.

I had already planned to get ARBs when it was run in, which I will still do. I would have also done this on the E90 had I kept it to sharpen it up a bit.

Maybe my expectations for an estate with saloon handling were too high.

I want to check / resolve these issues before I become 'normalised' to the E91 handling. 3 years of the E90 is still fresh in my mind, but as time goes on the E91 will take over as 'normal' and it becomes difficult to be objective.

[SixDegrees]

I haven't experienced any understeer, lots of over steer due to RFTs.

[ss134]

im experiencing the same with my new E90 335i m-sport, did you get to the bottom of this-was it the tyre pressures?

Thanks.

[NFS]

Just want to resurrect this thread.

I've also noticed some undesireable handling characteristics on my e90 335i msport.

The main issue is the way the chassis responds to rapid steering input at higher speeds. If I turn the steering wheel sharply at motorway speeds, the car turns in rapidly, but there is then distinct feeling of weight shifting and then re-settling a moment later.

I've not really cornered that hard at lower speeds in the car yet, but it feels as if you would end up in a nasty tank slapper if you tried a slalom test as the weight shifting seems unpredictable.

What's changed compared to the older msports? The ride is much more compliant on this car, which can't all be down to the Michelin runflats vs Bridgestone. It feels as if BMW have altered the suspension to improve compliance.

I'm guessing this is something to do with damper settings and rebound rates?

[Yahoo]

I am sure that the sloppy rear subframe bushes contribute significantly to the feeling at the rear end. Replacing them with the firm M3 ones resulted in a very significant improvement in how the rear end feels on my touring.

[ss134]

Originally Posted by NFS

Just want to resurrect this thread.

I've also noticed some undesireable handling characteristics on my e90 335i msport.

The main issue is the way the chassis responds to rapid steering input at higher speeds. If I turn the steering wheel sharply at motorway speeds, the car turns in rapidly, but there is then distinct feeling of weight shifting and then re-settling a moment later.

I've not really cornered that hard at lower speeds in the car yet, but it feels as if you would end up in a nasty tank slapper if you tried a slalom test as the weight shifting seems unpredictable.

What's changed compared to the older msports? The ride is much more compliant on this car, which can't all be down to the Michelin runflats vs Bridgestone. It feels as if BMW have altered the suspension to improve compliance.

I'm guessing this is something to do with damper settings and rebound rates?

My car now feels rock solid on the Autobahn at 150+ speeds, i can change lanes at very high speed with total contol and precision whereas before it felt very loose/not confidence inspiring............ When my car came from the factory it had a faulty steering pump which really affected the feel and control at high speeds (took 6 months to diagnose!)......as your car is also an LCI 335 built around the same time as mine it might be worth checking out the thread i started regarding the problem.

http://www.e90post.com/forums/showth...steering+fixed

[HighlandPete]

I'd be interested to know how this turned out as well. I run a touring and I'd say the rear spring rate is higher than the saloon, to cope with the loadings. I've not had the severe understeer, not sure that is really what is wrong, some strange and unpredictable 'snap' reactions on RFTs, but cured with normal rubber. If anything my car runs very close to neutral, on pressures above the lower placard rating.

As to cars being very different, I'd go along with that conclusion, no two cars seem to be the same, even in the same specification. Wheel and tyre fitment, plus ambient temperature have a large part to play in how we find the drive on RFTs.

HighlandPete