[muncie21]

It's been drizzling/raining off/on all day. Hopped on the freeway to run a few errands. On the way back (after driving ~50 miles no issues) home I'm passing this car (2 lanes each way) going about 75-80 and suddenly my rear end starts to slide side-to-side, like when you are on ice or losing traction. I let off the gas and ease over to the slow lane, thinking, damn my rear tires must really be worn or I've got low air pressure. Pull over and check things out, everything looks fine, rear tread is like 30-40%.

Pull in to a local dive and grab bite to eat. Getting back on the freeway, I gun it, to see how she feels; tires are planted normally and everything feels secure. Get back on the freeway and the same shit starts at ~60'ish MPH. The car is all over the road like there are ruts in the road or ice. Let me tell you, it ain't fun driving 50-60MPH with you car darting left/right on its own. BTW, this is completely random movement/darting, not predictable swaying like something is worn.

Going to read the DME for codes and check out the car more thoroughly later today. I'm thinking that the brakes were being applied at each wheel by the computer. Maybe it was thinking one wheel was spinning or something along those lines.

BTW, my ride is an '08 E92 335XI

[John 070]

Odd you even have awd......

[Wires]

Are you sure you have 30-40% on the rears (inside portion of the tires). Car has decent camber, and the insides wear faster than the outsides.

If you are low on tread, and there is enough water, it will hydroplane. On dry pavement with 2/32" on the inside edges, and 4/32" on the outside edges, my 335xi got really squirrely on road patches or manhole covers.

[BSM n54iS]

You have to realize also that RIGHT when it starts raining, or if barely wet roads, are the worst and slickest as all the 'oils' in the pavement are brought to the surface. Just sounds like you were hitting slick patches and your car assumed aquaplaning

[fareast1]

have you checked the lug nuts?

[bimmette]

Originally Posted by Wires

Are you sure you have 30-40% on the rears (inside portion of the tires). Car has decent camber, and the insides wear faster than the outsides.

If you are low on tread, and there is enough water, it will hydroplane. On dry pavement with 2/32" on the inside edges, and 4/32" on the outside edges, my 335xi got really squirrely on road patches or manhole covers.

Agree. Same thing happened to me before. Thought I was gonna die that day. Ended up getting new rear tires.

[Dark_Knight_335]

Did you turn off your DTC by chance?

[NGEE]

Originally Posted by Black n54is

You have to realize also that RIGHT when it starts raining, or if barely wet roads, are the worst and slickest as all the 'oils' in the pavement are brought to the surface. Just sounds like you were hitting slick patches and your car assumed aquaplaning

Seems as though he's saying it happened twice in the same night...not likely. I'm guessing alignment/tread-wear/under-inflation.

[muncie21]

Originally Posted by Black n54is

You have to realize also that RIGHT when it starts raining, or if barely wet roads, are the worst and slickest as all the 'oils' in the pavement are brought to the surface. Just sounds like you were hitting slick patches and your car assumed aquaplaning

I keep this fact in mind when riding my scooter, however this happened continually over the course of 30-45 minutes

Originally Posted by fareast1

have you checked the lug nuts?

Lug nuts, tire pressure and general suspension looks fine

Originally Posted by bimmette

Agree. Same thing happened to me before. Thought I was gonna die that day. Ended up getting new rear tires.

This seems to be the quickest/easiest solution. I ordered a set of tires to match the fronts (Conti DWs) which only have about 1K miles on them

Originally Posted by Dark_Knight_335

Did you turn off your DTC by chance?

I dicked around with the DTC; between the 3 modes I didn't really notice a difference. However because of the randomness of the problem, I can't rule out that one of the DTC modes was an improvement. However none, seemed to eliminate the issue.

Originally Posted by NGEE

Seems as though he's saying it happened twice in the same night...not likely. I'm guessing alignment/tread-wear/under-inflation.

This happened continually (albeit, randomly and intermittently) for like 30 minutes....30 minutes as 60-70MPH is like an eternity when every second you feel like you're about to spin out and crash

I slowed down to the point where Hyundais and 'that' Impala with the donut tire on it, sped past me

BTW, I checked for codes- None. What really sucks is that the car's nanny controls seem to be causing the dangerous issue. I would have NO issue driving the same speed and weather conditions in my other 'older' vehicles with these tires, or worse; which I admit, I've done before

[PhaseP]

Get your rear suspension checked just in case, anything loose, out of spec or order could cause it there.

Other comments/questions from me. Were your older cars fwd? Did they as much torque as your 335?
Your signature shows XI, but it is still RWD biased, and rumor is at some speed they become full rwd unless traction is broken.

Front wheels slipping is different than rear slipping. Rears are more scary if you are not used to because they induce spin off the car, and natural tendency to reduce speed suddenly when noticing slipping of the car exacerbates this with the rears. This is contrary to the behavior of front wheels losing traction.

Sorry if you are all familiar with this already, writing just in case.

[Rosetta Stoned]

Likely tread wear. Had the same thing happen to me this week with the rains. Car was almost hopping side to side in small jolts. I had to slow to 60-65 instead of the 75 speed limit. Just as soon as I did, a car passed me not too fast and he spun out into the divider. Normally I don't need to slow in the rain but turns out my rears have worn enough to lose that wet grip at speed.

[dawhiz]

Road grooves will throw you all over as well. I recently had an alignment, the front 2 tires were like a V with the point at the the front of car. Hit a pot hole that might have thrown it out. Traction wasn't great when jumping on it. Now that it's resolved, much different experience jumping on it. Much less traction loss, not the same feeling, etc.

[Levanime]

sounds like alignment

[BLKSAPPE92]

Probably unrelated but 2 years ago car was great in hard rain same tires, same tires but new only 3months ago with light to minimal rain car was hydro planning and darting.

Narrowed it down to 80k mikes and worn out front tension arms which can have an affect on caster and can cause left to right pulling and when a wheel hits resistance it will push that front wheel back causing different caster angles from left to right wheel and loss of control in wet weather

Torque your front wheels with torque wrench and see if front wheels have forward and back or have friend get in car and let off brake and slam it on quick if wheel shutters front to back with a quick brake apply from 5mph or less to zero you have a tension strut problem/caster issue

Replace control arms also replace struts to lower excessive movement and premature wear of bushings

[Miller335]

In freeway ruts I always thought it was called the stock suspension tuned 335 Boogie.

[NightStalker]

Bent rims, rear bushings worn, or needs alignment. Take it to a reputable tire/suspension shop

[Socket]

LSD will fix it

[335idle]

Driver Mod Yo

[DJtoad]

Originally Posted by muncie21

This seems to be the quickest/easiest solution. I ordered a set of tires to match the fronts (Conti DWs) which only have about 1K miles on them

Wait, you recently replaced your front tires but not your rear tires and they're worn down to 30%? That's an important fact to leave out and it's most likely your problem. You can't do that with an XI. The xDrive system will assume the difference in rotational speeds between the front and rear wheels is due to slip and will try to correct it through directed wheel braking, resulting in poor and unpredictable handling. It can also severely damage your drive train if the difference is great enough. That's why places like Tire Rack offer tire shaving services for people who need to replace one or two tires on AWD vehicles.

[924er]

Many 335i owners crashed the same way including rob beck. That's why he's done with this platform. He had LSD and good tires and still had this issue. Careful out there

[hassmaschine]

mismatched tires, AWD, rain.. I think it's pretty obvious.

[E9Slow]

Definitely get your alignment checked. I ran into this problem a while ago, where after getting new tires and alignment done, on just rainy days, if I even touched the brakes at highway speeds, my rear got wild and reckless too. Just recently brought it to a buddy at Firestone, and immediately he found my left rear toe adjustment bolt was completely loose, not even finger tight. Allowed that wheel's toe to change in those conditions apparently. He rechecked and readjusted all other wheels, tightened it up, and voila; car tracks like a dream again. Btw, this is an '07 e90 328xi. Hope this helps, and if you don't know anyone, Firestone has a one time alignment for about $65, not a bad price (comes with 6mon warranty, so you can take it back in 5mon and 29 days and get it readjusted again lol).

Good luck and drive carefully for now!