[mariopl]

Hi,

Is anyone expecting a problem with car not keeping straight line with high speeds, i.e. 170-180 and above.
That is also noticable with side winds - car needs wheel correction.

I have read a lot about this problem on german forum and solution was to fix toe.

https://www.motor-talk.de/forum/neue...90.html?page=9

Anyone faced that problem?

[MechX3M40i]

I let my reckless twin brother to borrow my X3 He told me that (wink wink) with the limited experience he had at > 100 mph (160km/h) he never experienced any 'float' or needed any more steer correction to keep the car straight than what he considers to be normal.

It's also normal to expect cross wind would impact a taller SUV body more so vs. a sedan (saloon).

[chicagofan00]

I've heard (but never tested ) that my X3 has run just fine at speeds up to 127MPH...

[Jayf30]

I have to correct it a lot when driving 75+ mph BUT this is in high wind areas. Otherwise the car is fine at high speeds

[mariopl]

Mine goes very straight beside cross/side winds forcing me to provide corrections especially with high speeds like 170-180km/h.
It is my first SAC / SUV and I am wondering if it is a matter of wheel/suspension/setup ?
Or perhaps It’s how such cars are behaving.
Previosly I had F34 (3GT) and it was resistant to cross wind.
Car also had M package but with 19” and M sport suspension, this one is 21” with series suspension.

[teaston]

Putting the adaptive suspension in sport mode should improve this, and fitting lowering springs will improve it further, I had to do this on my F30 335d to fix the float at motorway speeds. Fortunately the M40d doesn't suffer with this.

[mariopl]

When I had X4 30i demo on 20” wheels with adaptive, I couldn’t find any difference when switching modes. Almost same sporty and harsh feeling.
Being experienced I have decided on standard suspension which is firm but not harsh. For that I opted for 21” wheels.
What I am suspecting at first glance is tire pressure - set for all 4 wheels on 2.5 bar Where sticker says 2.4/2.9 front/back.
I think it might be a hint to improve handling.
Next step is to check wheel convergence (toe in).

[mariopl]

Originally Posted by Jayf30

I have to correct it a lot when driving 75+ mph BUT this is in high wind areas. Otherwise the car is fine at high speeds

Hey, so you are saying that you facing similar problem? Do you feel "plushy/floaty" ride in open areas when driving fast?

[Tokke]

I did 217kph in germany this weekend and i was surprised how Stable and planted the car was with this speeds. Much more stable than my F30 before.
My car has 20inch wheels, pirelli RFT and the adaptive suspension was set to sport.

[mariopl]

Originally Posted by Tokke

I did 217kph in germany this weekend and i was surprised how Stable and planted the car was with this speeds. Much more stable than my F30 before.
My car has 20inch wheels, pirelli RFT and the adaptive suspension was set to sport.

I am wondering if having adaptive suspension is an advantage to drive fast and stable...
I had a DEMO with adaptive same on 20" with RFT as you but suspension was too hard for me (even on comfort). Standard is compromise to me between sport and comfort.

[Jayf30]

Originally Posted by mariopl

Hey, so you are saying that you facing similar problem? Do you feel "plushy/floaty" ride in open areas when driving fast?

Exactly. It doesn't feel as grounded but I'm used to it now, there's a few highway sections I frequent with moderate - heavy crosswinds.

[Tokke]

Originally Posted by mariopl

I am wondering if having adaptive suspension is an advantage to drive fast and stable...
I had a DEMO with adaptive same on 20" with RFT as you but suspension was too hard for me (even on comfort). Standard is compromise to me between sport and comfort.

I test drove a x3 on 20inch wheels with both the standard and the adaptive dampers. I found the difference small, but noticable. For me iT was always a must have to have the adaptive dampers. But i remember that the difference on the F25 was much bigger.
Now when i took delivery from my car with the adaptive dampers the ride was extremly hard. So i stopped at the first gasstation to check the tire pressure and all 4 wheels were set to 2.9 Bar. I lowered the pressure to 2.2 in the front and 2.4 in the back. The car runs great like this.

[Richierich32]

Originally Posted by teaston

Putting the adaptive suspension in sport mode should improve this, and fitting lowering springs will improve it further, I had to do this on my F30 335d to fix the float at motorway speeds. Fortunately the M40d doesn't suffer with this.

Hi mate

You still running runflats on yours?

[AndroidRobot]

when I had mine I bounced off the limiter at 250kmh and it was fine. I guess the roadway surface would be a big factor here. No road is perfectly smooth so any small deviation can make it feel floaty especially when downforce isn't exactly the greatest.