05+ Driving on thin ice/snow

[leftride]

back on topic...(I also cross posted this on subaruoutback.org)

 

Well I guess I'll post here since I have now had this happen to me twice (at least twice it was very noticeable)

 

My first experience was going on a straight flat road, which was ice covered and it was VERY unsettling. The back end would "wiggle" and it was hard to keep it going in a straight line. At that time there was a decent cross wind so I attributed it to that.

 

My experience today was on the interstate, ice covered, and the same feeling, but not quite as bad (I have since replaced the RE92 tires, but I have gone to an 8" wheel, which I would assume would just make snow driving worse)

 

Both times it seems I have had a full load, 5 people in the car, ski stuff in the back and 5 skis/snowboards on the top.

 

I have driven numerous time with only my wife in much worse conditions and I have not had any issues. Granted it's hard to compare conditions, but I do feel more stable with 2 people and 2 skis, rather than a full load.

 

Either way, it's not a fun feeling and all I can seem to do is slow way down and let people pass. I'd love to have an explanation, cause it sucks.

[ehsnils]

Either way, it's not a fun feeling and all I can seem to do is slow way down and let people pass. I'd love to have an explanation, cause it sucks.

 

I can surely understand that this is a problem.

 

There is a difference between the manual and the automatic transmission - so the behavior you experience will depend somewhat on that too. The manual transmission has a 50/50 distribution of the torque between front/rear while the automatic has a 60/40. Since I haven't compared them myself in real life I can't really tell if there is a noticeable difference.

 

However these data aside - since the rear end of a Subaru is a multi-link setup the wheel alignment will change depending on the load of the car. A heavy load will change the alignment a bit compared to no load. And if the alignment isn't good from the beginning or if the suspension starts to get a bit worn it will cause a little pre-tension in the contact area between the tire and surface which will allow the tire to break loose easier.

 

To come to terms with this you may want to check the wheel alignment on the rear wheels after you first check and replace any worn parts. If you have the habit of often varying your degree of load you may want to have a self-leveling suspension, which may be achieved by the Boge Nivomat shock absorbers. http://roversd1.info/misc/suspension.html This will level out the car after driving some distance and therefore cause the suspension to be positioned for the "normal" alignment.

 

Of course - a car is very much a dynamic system in motion and the Subaru cars have a very balanced weight distribution when unloaded. This means that they work very well when unloaded and doesn't fall victim to the extreme understeer that you can experience with many other cars, but at the same time a load can cause this to change - in a way that causes the rear end to be heavier than the front end. In this case it will be something like throwing a dart with the rear end first when you lose grip.

 

A rule of thumb says that you should have the best tires at the rear end to avoid unpleasant situations. However - with the AWD system you shal have a symmetrical set of tires (when it comes to dimension and wear), but this doesn't mean that you must have exactly the same model of tire front and rear, just that they have to have the same circumference when inflated. But here is where it becomes tricky - if you experiment with different tire-setup front and rear you may end up with a lot more inconsistent behavior, so it's only for those who really has time, patience, money and a test track.

 

Many of the problems with varying conditions and dynamic stability is targeted by the VDC (Vehicle Dynamics Control) system. This is like the ABS system both a blessing and a curse. Works good on the car when you use that car - but change to a different car without these features and your reflexes are wrong. Another problem with systems like VDC is that you may miss the early warnings you otherwise get (like the sensitive tail-end) that tells you to slow down. A warning light doesn't sharpen your awareness nearly as good as a slight twist.

 

One experience I have when it comes to the oversteer tendencies of a Subaru is that it makes itself "known" by wiggling the end a bit but it seldom gets excessive. The difference here is that this is a rear end that gets of early in a relatively mild manner. Other cars may be completely different - having a straight track and when they lose it they are going completely off the track instead in a completely uncontrollable manner. (I have had a rollover in a Volvo caused by this , sorry no pictures - but nobody got seriously hurt - not even the car even if I had to change two fenders and two doors. Only my pride...)

[BayScoobie]

I experienced the tail wagging problem on my 2005 LGT wagon a couple weeks ago. The wagon has Michelin Pilot Sport tires and was lightly loaded with one passenger, 2 snowboard and ski jackets. The highway has been plowed and was completely dry. The temperature was around 20deg. Every car/truck was going at the speed limit of 55mph.

As I was approaching an overpass, I noticed a patch of ice spanning the width of the road directly under a bridge. The road section was perfectly straight, so I reduced the throttle slightly to let the car ride over the ice. The car was composed as the front wheels moved onto the ice. When all four wheels were on the ice patch, the rear started swinging in a left and right motion with the pivot point at the engine compartment. When the car moved back to dry pavement, it regained composure immediately.

At no point did it felt like the tail end was going to spin around but it was disconcerting.

[cowdog]

I experienced this rear wagging a couple of times this year. 07 OB XT (manual) with VDC - winter tires are Dunlop WS M3. This year's winter weather has given us lots of icy road conditions versus our typical packed snow conditions. On the road to the local ski hill, one I have driven 100s of times each winter for decades, I have had the rear of the car wag back and forth while driving at a constant speed in a straight line. It is so unnerving I slow way down and have pretty much every other vehicle pass me. I also had this happen recently while driving I-90/I-25 in Wyoming. The roads were horrible, probably the worst I have ever experienced. At one point the car drifted to the left, into a very strong side wind, and I was the by far the slowest traveling vehicle on the road at about 40mph.

 

In nearly all other snow, packed snow, snow/ice mix conditions the car is rock solid. I am a very experienced winter mountain driver. This is the craziest feeling. VDC on/off does not seem to matter. It seems to happen on relatively consistent icy road conditions at speeds of 40-55 mph when going in a straight line. Folks are welcome to challenge my driving, but I can assure you, that was not the issue. Something in how this car transfers torque from side to side in these kinds of conditions seems to resonate and translate into side to side movement of the rear of the car. I have been in similar conditions, even recently, in other vehicles where this has not happened, even at higher speeds. For example, my 97 4runner did not have this problem on the same road on the same day this year.

[slimjoe]

This past Thursday, I was driving a friend up from NJ to VT (Mt Snow area). It was about 2, maybe 2.30am when unknown to me, the rain that was falling started to freeze and left a small layer of ice on the roads.

 

The first sign that I felt was from the front end of the car when I was going at about 50mph. It felt like it was hydroplaning slightly when I was going around corners. From there, I was able to go a few more miles (and about 2-3 minutes later) when I definitely felt the loss of traction. I don't remember what ticked me off to that, but I immediately started to slow down and traveled at a crawl of 10-15mph, just hoping to make it to the house (which was about 18 miles away).

 

From that point, I was able to drive for another minute or two until we made it up a hill and I saw a tractor trailer off on the wrong side of the road, as if it had skidded off and ended up in the left guard rail. It was finally there that we decided to stop, call it a night, and park the car off as far as I could in the right gravel shoulder (to keep myself from sliding down the hill or whatever). After we stopped, I stepped out of the car to get some stuff from the trunk and almost slipped. The ENTIRE road surface was covered in a sheet of ice probably 1/8" thick.

 

Anyways, enough of the story and back to the point. It was only at the end when I slowed down/stopped at the sight of the trailer and when I tried to bring my car to a safe parking spot off the side of the road did the rear ever push forward. However, it was nothing that wasn't easily controllable with a little bit of opposite steering.

 

Without the AWD given to us in these cars, there is no way I would have made it as far as I did and it probably would have been much worse off when I first noticed the signs going around the bends (if I was in a FWD car).

[Richard B.]

I can surely understand that this is a problem.

 

There is a difference between the manual and the automatic transmission - so the behavior you experience will depend somewhat on that too. The manual transmission has a 50/50 distribution of the torque between front/rear while the automatic has a 60/40. Since I haven't compared them myself in real life I can't really tell if there is a noticeable difference.

 

last i heard. my 5eat was 55% rear 45% front.

[ehsnils]

last i heard. my 5eat was 55% rear 45% front.

 

That's interesting - I did read the spec's for the '08 which clearly stated 60/40 front/rear. (OK, the Swedish specs http://www.subaru.se/legacy_sedan_spec.aspx), but I hardly think that the transmission figures are that much different between the markets.

 

However - what may be interesting is if this phenomenon is specific to the AT or if it is on the MT too, since the AWD transmission is different between the AT and the MT. The MT has a differential with a visco-brake while the AT has a hydraulic clutch, which essentially means that there are two relatively different AWD systems depending on the gearbox.

 

Maybe the figures you are referring to is the weight distribution of the car when fully loaded?

[jazzymt]

FYI - 5EAT & 5MT XT owners on sob.org have both reported the problem.

 

This is not an oversteer issue & it's not a winter driving issue. The POINT is that this car has something that causes the rear end to "resonate" side to side when on ice and feel severely unstable at speed much lower than everyone else on the road.

[krzyss]

Could presence of rear LSD explain such behaviour?

If it locks/unlocks it may cause some side to side movements I think.

 

Krzys

[STG]

Some of you guys are one-car accidents waiting to happen:

 

"My car wags its tail on ice only 1/8" thick!"

 

Keep trying to defy the laws of physics. Keep installing stiffer springs, shocks and sway bars. Do not bother to learn how to use your right feet.

 

You really need a reference point. Go to your Ford dealer and test drive an unloaded F250/F350 4X4 in winter conditions. Almost 600 lb./ft. of torque will have the tail dancing on dry, wet, or icy pavement. Half of you would probably ground loop the damn thing in August.

 

I should buy stock in a coffin manufacturer.

 

P.S.: Somebody please tell me, what is the difference between driving on 1/8" ice and and a frozen lake?

[DukeTrout]

Some of you guys are one-car accidents waiting to happen:

 

"My car wags its tail on ice only 1/8" thick!"

 

Keep trying to defy the laws of physics. Keep installing stiffer springs, shocks and sway bars. Do not bother to learn how to use your right feet.

 

You really need a reference point. Go to your Ford dealer and test drive an unloaded F250/F350 4X4 in winter conditions. Almost 600 lb./ft. of torque will have the tail dancing on dry, wet, or icy pavement. Half of you would probably ground loop the damn thing in August.

 

I should buy stock in a coffin manufacturer.

 

P.S.: Somebody please tell me, what is the difference between driving on 1/8" ice and and a frozen lake?

 

You might have better traction on the lake. With a thin layer of ice over the road, the surface is inflexible. On the lake, the slight flexion of the ice as the wheel passes over it might increase the contact patch and improve the traction. Maybe.

[DukeTrout]

FYI - 5EAT & 5MT XT owners on sob.org have both reported the problem.

 

This is not an oversteer issue & it's not a winter driving issue. The POINT is that this car has something that causes the rear end to "resonate" side to side when on ice and feel severely unstable at speed much lower than everyone else on the road.

 

jazzy - I've driven the 05 OBXT on just about every low- to no-traction surface available and the only mods I have are different 17" x 7" wheels and studded winter tires. I've never detected this wiggle you describe. Heck, there's more wiggle at speed on dry roads than I've noticed on ice or snow. Maybe it comes down to that - whoever is noticing the wiggle simply needs to slow the heck down.

[jazzymt]

Some of you guys are one-car accidents waiting to happen:

 

"My car wags its tail on ice only 1/8" thick!"

 

Keep trying to defy the laws of physics. Keep installing stiffer springs, shocks and sway bars. Do not bother to learn how to use your right feet.

 

You really need a reference point. Go to your Ford dealer and test drive an unloaded F250/F350 4X4 in winter conditions. Almost 600 lb./ft. of torque will have the tail dancing on dry, wet, or icy pavement. Half of you would probably ground loop the damn thing in August.

 

I should buy stock in a coffin manufacturer.

FYI - my Chevy 2500 HD w/6.0L V8 and stock tires drives like it was on rails compared to my 05 XT w/Tripletreads even in RWD (on ice).

 

You can assume all you want, but I'm not an incompetent driver. I'm aware of what's required to keep my vehicle under control in the worst of conditions - I've been driving them my whole life and have never been in an accident. That said - my XT is downright terrifying on ice and I've never experienced anything like what it does in any other vehicle & apparently - neither does anyone else passing me on the roadway when it happens.

 

I've tried everything I can think of (tires, alignment, different payloads, etc.) and most of those help a little, but none eliminate it.

 

Once again - this isn't an oversteer issue - the car's rear end oscillates on the road at about 1Hz, I figure about 2-3" back and forth. It's about the most unsettling thing you can imagine to be driving down a slick road and have the car not just be unresponsive - but practically *fight* you for control. Off throttle, on throttle, braking - none of it makes any difference.

[leftride]

exactly it isn't an oversteer issue or even really the feeling of loosing forward traction, it is an oscillating wiggle in the rear of the car.

 

I like how everyone just assumes it's bad driving. No one is saying 'my car keeps sliding into a ditch when I try to pass people doing 80 mph on a icy road'.

[Domain]

This topic is pretty hot on the Outback Fourm, I was wondering if 05 and newer Legacy owners have the same issue/feeling.

 

I can't be sure if the weather conditions/icing that you describe could be compared to the relatively "light" winter weather we've had since I moved to the area, but I can say (thankfully) that neither my '05, or my recently purchased '08 have experienced this "oscillation" that you and other have described. You can certainly make the car "tail-happy", but even then it is quite controllable.

 

On the other hand, I have a tendency to drive very slow in wintery weather, especially if I know conditions call for icing on the road. Regardless of what the other drivers are doing, i'll hold my speed at a level *below* what I feel is safe, and if the other drivers don't like it, too bad... they are free to pass me, and I'll be free to laugh at them when they are wrapped around a tree (or other road hazard).

 

As for some comments regarding traction control... my brief experience with the spec.B's (VDC they call it?) was somewhat unexpected, and certainly unsettling. Given the choice (and thankfully there is one), I prefer to turn it off...

 

Of course, take what I have to say with a grain of salt... I was the idiot that was stuck out in 6" snowfall on new years in a fairly new car riding on RE050's (That was one white-knuckled experience I don't want to repeat)

[cowdog]

Some questions:

 

OK, latest drive on icy, mixed-condition roads and I can't keep up with general traffic, including lots of FWD and RWD cars without snow tires. I feel like my OB is on the edge of control with the rear end sliding side to side. Me, 07 OBXT (5SP) w/ Dunlop WS M3 tires. Something is amuck when I'm passed by an older woman driving a civic without snow tires. It seems to be getting worse.

 

I am taking my car into the local dealer tomorrow to talk about this issue and to have the rear alignment checked. What other options might I have? As it is the suspension feels very soft to me. For example, when I accelerate the front of the car rises (or the rear sinks). Should I look at some different suspension options? I'm willing to try most anything. This is nuts.

[heh2k]

You're always going to have some front rise when you accelerate. The firmer your suspension, the less rise.

[LongHiway]

I wonder if this issue is not mechanical per se' but, the internal logic on how power is getting sent forward or backward?

 

I hydo-planned real bad a few months ago, seemed like my rear end had all this power, trying to push ahead of the front.

[STG]

I wonder if this issue is not mechanical per se' but, the internal logic on how power is getting sent forward or backward?

 

I hydo-planned real bad a few months ago, seemed like my rear end had all this power, trying to push ahead of the front.

 

Jeez! Give it a rest! If you "hydo-planned" (sic) "real bad", by definition your car had zero traction.

 

How the hell is your Subaru supposed to figure out how to allocate power with all four tires disconnected from the road?

 

You might as well put the car on a chassis lift and ask the same question with all four spinning in the air.

 

:spin::spin:

[LongHiway]

I guess you are right on. Thanks.

[holter95]

Jeez! Give it a rest! If you "hydo-planned" (sic) "real bad", by definition your car had zero traction.

 

How the hell is your Subaru supposed to figure out how to allocate power with all four tires disconnected from the road?

 

You might as well put the car on a chassis lift and ask the same question with all four spinning in the air.

 

:spin::spin:

 

Hey STG - what the hell crawled up your a**... seriously? I've been on this thread 5 minutes and all I see is your incessant kvetching because people don't necessarily agree with you. Get over yourself and let people try to figure this out without your trigger-happy, half-cocked, self-righteous retorts. Just because you've never experienced it doesn't mean it's not for real.

 

I've experienced this problem, and I have enough miles logged on dry, wet, snow, ice, FWD, AWD, and virtually every type of vehicle to know this is not normal (the beat-to-holy-snot-bald-tired rental Taurus I had in SLC excepted). I've got a pretty firm grasp on vehicle dynamics (having worked in vehdyn for an OEM) so I know what I (and others here) are talking about.

 

- This is NOT oversteer (how many times must it be said).

- It happens steady state, at speeds in excess of 30 mph on icy surfaces

- It happens with little to no throttle input - NOT under braking, lift-throttle, or heavy throttle application

- It does NOT appear to be an issue in deeper snow, nor on wet or dry conditions

- It happens when tracking STRAIGHT - not when negotiating a curve.

- It's a side-to-side or slight yaw motion akin to being blown around by stiff side-winds

 

From what it appears here too, it doesn't seem to necessarily be a Legacy problem as much as an OB... of course data points on that differentiation are weak so far because this thread can't get past the b*tching and slander far enough to be constructive in figuring out the problem.

 

Point is - we're looking for ideas for a cause or solution. If it hasn't happened to you, you're either fortunate enough to not have the issue, or you aren't understanding what we're talking about. If you've got nothing useful to say, then go stir up crap elsewhere.

[Sarra]

Rear suspension geometry. Or maybe tires? I dunno, my 98 LGT has the opposite problem, understeer on low grip situations. Going to get a turbo FSB, and a thicker RSB to see if I can fix it.

 

I would say "slow down", but I've personally gone 50+ on ice, so I haven't really got any advice or other knowledge that would explain a tail happy Legacy on ice.

[reason22]

Another data point. Yesterday in St. Louis we had an inch or two of "ice pellets"...like icy ball bearings on the road. Not as bad as smooth ice, worse than snow, and pretty exciting driving.

 

This time, and in the past, my 05 Legacy GT wagon 5MT has not had this tail-wagging issue. It does do 4-wheel power slides very well, heh heh.

 

Car is bone-stock, with three-year-old RE92's on it...and I did get up to 40-45mph on some stretches of straight 4-lane road with no traffic...just for fun.

 

So at least one LGT with no issue. It sounds from the detailed descriptions to be an actual issue. I'm thinking along the lines of left/right torque distribution, too. Good luck.

 

edit: at least in my experience these cars (stock) understeer like a mofo! Maybe not as bad as a Toyota, but lots of front-end push going on...

[holter95]

^^^ yeah, around town they definitely understeer in the slick. The Turbo (and MT) really do make for quick oversteer though when you get on the gas.

 

Thanks for the input. It's interesting because there's very specific road surfaces that encourage it.

 

I have to sift back thru this thread - but it seems like most... if not all... people who encounter this have OBs... wonder if the ride height - and resulting drivetrain angles - have anything to do with it?? May be a bit hokey, but right now nothing is off limits for possible culprits.

[ehsnils]

The large variation in behavior seems to indicate that the wheel alignment may be off on some cars. Or even worse - that the assembling of the cars aren't consistent.

 

I have experienced that with AWD the car begins with understeering, but as more power is applied it passes over to oversteering. The trick is to apply the power consistent to get a four-wheel slide - or to go for the low-speed non-slide control. Practice on an empty parking lot and try to get the feel for it!

 

Tires and tire pressure are otherwise the most important factor. I usually use about 0.2 bar overpressure on the tires when I check the pressure, mostly because a slight overpressure is not as bad as an underpressure and as long as the tires are consistent in pressure the behavior of the car will be consistent.

 

I never had any problems with smooth ice with any of my Subarus (1800 -82, XT -86, Legacy -92 and now Legacy -04), but it may be to the fact that I always have been using studded tires. (which are legal here)