Understeer?

[mike_dmt]

Had a chance to drive my new to me '01 X5 in the snow over the weekend, and noticed a considerable amount of understeer in off throttle turns.

Have 18" Goodyear snow tires, non-studded, probably 60-70%,tread left with even wear.

Tons of traction under power, even with traction control off, but like I said as soon as I was off throttle(with TCS), it was on the edge of being complete crap.

I've had AWD and 4X4 vehicles before, dozens actually, and I've grown up driving in snow.

I'm wondering if I can blame the tires? Or the fact that it's got a heavy V8 in the front of it... Anyone else notice this?

Is it possible the transfer case and TCS system have a software upgrade?

[SlickGT1]

I don't get your question. You should be under throttle in an AWD truck in a turn. You don't have to be flat on the pedal. You will get understaffed because off throttle, you load up the front with the momentum of the truck. I used to race a bit (for myself only for fun). You should be breaking before the turn, which loads up the front, giving you that traction, and you should be under throttle in the turn. These trucks are super fun. The more throttle, the more the rear comes out. You just need to get used to a proper fun truck.

[J.Belknap]

If you're just mucking about in a parking lot or something, disconnect the brake fluid level sensor for maximum fun.

[SlickGT1]

LOL, I am definitely not ready for that much fun. Still trying to get used to a huge truck feeling like a sedan. Lots of fun so far. Came out hands shaking a few times, but getting a better hang of it. Can't wait for snow.

[Helmuth]

My findings with the 3.0d in the Alps, where we have enough snow right now: the X is not good in snow. Maybe too heavy, maybe I have the wrong tires (Hankook Icebear 235/65/17), maybe I am to stupid to drive.

Seriously I am absolutely disappointed - the last car I had to let pass was a Dacia Duster (you can buy 5-8 Dusters for the prize of an X5). If I had followed this guy I would already be dead. And that is not a joke on the road I was.

Give me a chance and tell me that my winter tires are not good enough......

Best, Helmuth

PS: and mike_dmt - yes but I believe that is normal. You would need to keep speed to avoid that. Of course only if hou haven't been to fast before :-)

[Turbo_Bimmer]

I also feel the front a bit heavy on the X. That, plus the fact that all manufacturers 'tune' their cars to have a tendency to understeer (safety reasons for the average driver), the X will have a tendency to slip from the front at it's limit (quite low on snow or under rain).

From my little experience playing with suspensions, I found on my E30 (325ix), that had a big understeer problem under rainny conditions, that installing a bigger rear sway bar helped a lot. I went from a car that was not able to keep the pace with a RWD under rain, to a AWD monster with lots of traction in turns :-)
I'm not expert on suspensions, but I think that stiffening the rear, will transmit some weight on the outside front wheel and make the grip better.

It's not on my priority list because my X is a family vehicle, but may be one day I will install a bigger rear sway bar for a better feeling.

Oh, FWIW, when I want to have fun with the X on snow, with the DSC OFF, I found that turning the steering wheel more than needed will help the rear to go around (half turn instead of quarter of a turn for example + some gas).

[mike_dmt]

In town it's not an issue. And, I'm more than comfortable with the back coming out under power, but thats simply not a good idea driving down a 2 lane mountain road in the snow, with other drivers coming up.

It happened a few times on my way down, slow down early enough, try to turn in to the corner, and the car just pushes. Even under braking, it was no better. Under a bit of power and braking it was not much better.

At one point it took a guy behind me in a 3/4 ton Dodge Ram by surprise. I had to almost stop in order to get around the turn.. I would think if it was slick enough for me to slip, he should too, with a big diesel engine in his truck.

I'm starting to think about different tires.

[SlickGT1]

Yea I have a feeling your tires are not up to the task in your conditions. Also, it is a good idea to mount snow tires on the thinnest rim you can find. The wider the contact patch, the more the snow will be compacted and you will not be able to dig in properly.

I'm from Russia, so lots of experience with this. Especially being a dumbass at one point and putting snow tires on a 10 inch wide rim once. That was a total waste of money. Glad I was able to unload the setup.

I bought a set on here from LeMans. Forgot the name of the tires, and didn't get to try them out yet. I had blizzaks on my last car, and they were amazing. It was a RWD Lexus GS430. Also a V8 out front, but no AWD to assist. I was able to drive the car as long as the snow wasn't over the bumper.

Also remember, your car will under-steer under braking in the snow. You really need to be turning while rolling. So if you are on the brakes in the turn, you are trying to apply 2 different forces to the tire. One to stop, and one to turn, this limits the performance, of both characteristics. The tire now doesn't have the proper grip to stop, or turn. So it will take the path of least resistance, and go straight.

Try this in a lot or something.
Slow before the turn, wheel straight, and try rolling through the turn (no brakes), apply throttle as necessary.

Just remember, turning under braking is never a good idea. You must keep you tires rolling to negotiate the turn. If you lock, or abs the wheels, you will not be turning.

[sprocket1200]

I agree with Slick. $100 says its the tires. Let us know the model of Goodyear tires, age (from date code) and tread depth. something is fishy....

[mike_dmt]

Slick, I appreciate the input. Not to be arrogant, but I already thought through most of what you had to say. But again, thanks.

Sprocket, I think they're Goodyear Ice Grip something something... Lol. Date code I'll have to get later. As far as tread depth I'd say maybe 65%-70%..