Best Practices for Open Diff Driving in Snow

[Kgolf31]

Originally Posted by HeelToe

Not too much you can do. Good snow tires. Narrower are better. I put 17s with 215s on my 330 instead of 18s with 225s. Full tank o gas. lsd works wonders in the white stuff. No master driving tricks that I've found though.

I suppose lifting the car a couple inches may help in the deep stuff.

I run 205s

Originally Posted by granracing

Expecting a non 4WD or AWD car to do well in 7" of snow isn't realistic. In a couple of inches, oh yeah!

My wife was asking my how I feel so confident in the snow. I also LOVE racing in the rain, which many of the general approaches and techniques carry over. For snow conditions, here are a few tips:

* Snow tires are key. I had a Civic si with decent tires and struggled to get the car up even minor hills. I later put on good snow tires and the car was absolutely fantastic on snowy roads. There's a huge difference.
* Know your personal driving and car's limitations. Just because you can get going okay doesn't mean you can stop or turn.
* Less is more. My goal is to provide the car the least amount of inputs necessary. Turn as little as possible, brake lightly, throttle smoothly. Unless you're having fun in a fairly controlled environment.
* Braking - no matter how confident I feel, I brake for an intersection early and smoothly. You never know when there is black ice under the snow.
* Confidence. This is HUGE as previously stated. If you know what the car will do under various situations, you'll be prepared. If you slide, do NOT panic.
* Looking forward. Don't stare at the car or road just directly in front of you. Look further ahead. Your car will go where your eyes will.
* Turn right to go left. Couldn't help mention a Lighting McQueen line! It's true, if you are sliding undo the steering wheel a bit, then gradually provide more input.
* Know where you can take "risks". I don't mean be stupid. Feel out the conditions a bit. You're coming to a stop sign with no cars, people, or items you could hit. Brake early and harder than you normally would. How does the car react in those conditions?
* Go at your own pace. I admit that I get frustrated when someone in front of me is going slow, but if that's all they feel comfortable doing safely they should keep going at that pace. Don't let other drivers pressure you. If you find a safe place to do it, pull over and let them go by. Nothing wrong with doing that.

I apologize if that was too basic and not entirely what the OP was talking about, but maybe it'll help at least one or two people.

Good tips that should be noted. I always do brake checks and purposely lock up the brakes to see what the car is capable of in crappy conditions when traffic isn't present.

As for looking forward, good little tip: If you're looking at a ditch you're going to end up in that ditch.

As well, correcting steering is something I commonly do autocrossing, it really becomes muscle memory when you start to feel any tire starting to slip.

[JB007]

Nokian tires on BMW recommended size, and the 135i transformed into a fantastic winter car.
It's really that simple.

[Kgolf31]

BTW, I figured I would update this thread.

Threw some E92 wheels on the rear axle that have Michelin Ice-Xi2 tires on them.

No problems getting up inclines while sitting, also found some powder to play in...no problems as well. Clearly the tires are to blame.

Trying to sell off the LM-25s and going with Ice-Xi3s

See thread: Good read: http://www.bobistheoilguy.com/forums...pics/3063887/1

[Lucky1]

Originally Posted by Kgolf31

BTW, I figured I would update this thread.

Threw some E92 wheels on the rear axle that have Michelin Ice-Xi2 tires on them.

No problems getting up inclines while sitting, also found some powder to play in...no problems as well. Clearly the tires are to blame.

Trying to sell off the LM-25s and going with Ice-Xi3s

See thread: Good read: http://www.bobistheoilguy.com/forums...pics/3063887/1

Curious how did you confirm there was only one season done on the tires? And more importantly how many km's were done on them?

If they have good tread depth and aren't cutting it thats bad for a premium winter tire brand.

[T1T2GRE]

Huh. I don't have these LSD snow issues. Oh, wait, I have a 128

[Kgolf31]

Originally Posted by Lucky1

Curious how did you confirm there was only one season done on the tires? And more importantly how many km's were done on them?

If they have good tread depth and aren't cutting it thats bad for a premium winter tire brand.

3500 miles (I'm at 5500 miles total on the tires now), tread depth is around 8/32nds. Production date of the tires corresponds to story being told when I bought.

Anyways, the compound just sucks. Today (-10F) the tires just gave up. No traction on the dry let alone any traction on covered roads. Hard as a rock, you could feel it as you drove the tires were just hard.

Ordering Michelins tomorrow, can't wait any longer

[Overpar56]

My best practices:

1) watch 11PM news. Evaluate all the white death doom the talking head says about how much snow their UltimateFirstwatchMegasupperDopler radar indicates.
2) take two Ambien along with a cup of NyQuil.
3) curl up into fetal position with covers over my head
4) wake up March 15th.

[TheSt|G]

Originally Posted by Kgolf31

3500 miles (I'm at 5500 miles total on the tires now), tread depth is around 8/32nds. Production date of the tires corresponds to story being told when I bought.

Anyways, the compound just sucks. Today (-10F) the tires just gave up. No traction on the dry let alone any traction on covered roads. Hard as a rock, you could feel it as you drove the tires were just hard.

Ordering Michelins tomorrow, can't wait any longer

Fantastic move. I have them on the fiance's ZHP and it is a complete snow tank. My personal next snow mod is the Quaife. I'm at my limit with this one wheel drive nonsense.

[JimD]

We do not have frozen precipitation here but I have further evidence that compound is probably not the issue. The temperature as I drove to work was in the low teens. We came in my 128 with it's Michelin Pilot Super Sport (summer high performance) tires. No problems at all. Handling normal, ride normal. I wasn't pushing it, never can tell where a patch of ice might show up, but under normal driving conditions these summer tires were fine.

I wouldn't attempt snow unless it was for a fun test with these tires. But cold weather just isn't a significant issue.

I suspect the difference between good snow tires and so-so ones is a lot more the tread design than it is the compound.

If it snows here, happens about every 5 years, I would use my SUV with it's all season tires. But if I needed to use my wife's bimmer with it's all seasons I would without worry. I've driven in snow for decades on all season tires. They do not give you as much traction as good snow tires but they will get you around fine if you are careful. I'm not trying to be critical of people who want the best tire for the conditions. I am just observing there are other ways to get around.

Jim

[Kgolf31]

Originally Posted by JimD

We do not have frozen precipitation here but I have further evidence that compound is probably not the issue. The temperature as I drove to work was in the low teens. We came in my 128 with it's Michelin Pilot Super Sport (summer high performance) tires. No problems at all. Handling normal, ride normal. I wasn't pushing it, never can tell where a patch of ice might show up, but under normal driving conditions these summer tires were fine.

I wouldn't attempt snow unless it was for a fun test with these tires. But cold weather just isn't a significant issue.

I suspect the difference between good snow tires and so-so ones is a lot more the tread design than it is the compound.

If it snows here, happens about every 5 years, I would use my SUV with it's all season tires. But if I needed to use my wife's bimmer with it's all seasons I would without worry. I've driven in snow for decades on all season tires. They do not give you as much traction as good snow tires but they will get you around fine if you are careful. I'm not trying to be critical of people who want the best tire for the conditions. I am just observing there are other ways to get around.

Jim

I'm going to argue with you 100% that compound IS indeed, a root cause.

Running Hankook RS3s on my Z4M, the tires are very sensitive to temperature. Running from 90 degrees to 40 degrees, grip drops off a cliff below 65 degrees. Tires (summer tires especially) are made for optimal temperatures.

Just like these Performance Snow Tires, they aren't made to tolerate lower temperatures, but are made to tolerate higher temperatures than normal studless snows. Tread design may be an issues, but they clear snow perfectly fine.

If tread design was the only factor, wouldn't all tire companies come to the same conclusion on tread design?

Anyways, Ice-Xi3s ordered, should be at my door tomorrow. Will be delayed mounting due to TPMS sensors ordered, but by next week I should be ready for real snow

[JimD]

While I didn't push it this morning I did corner hard enough to get the wife's attention with the temperature around 30 using the summer Michelin's and it held it just fine. I don't plan to play racer but I wouldn't with different tires either. Cold weather driving is more survival than fun to me and the street is a poor place to find limits regardless.

With respect to why different manufacturers use different tread patterns I think it is a different balance of the various factors. If you optimize snow traction, you give away dry traction and possibly wet traction too. Plus you do something to noise. Wear rate may also be affected by tread pattern.

I'm not saying there is no difference in compound, there is, just that it is a secondary factor IMHO. The main reason snow tires work so much better in snow is they throw the snow out of the tread. Tires that do this really well dig into the snow maximizing the available traction. My summer tires would be terrible at this. All season better. Good snows best.

Jim

[alexmtl_135i]

Nope, nope !
That's a very dangerous idea to spread... Michelin PSS are very good tires but not in the winter. Of course, ANY tire will drive just fine in cold temperature as long as it's dry and you're not pushing it...

Now try to do an emergency braking with your PSS with -10 degrees celcius... Totally different story. And you'll be *useless* with the tiniest bit of snow.

A couple years ago I was driving in 0°C temperature, dry road with an M3. He overtook me before the corner, though he had time to brake, ended up sliding straight in the side wall, car flew in the air and all.

Simple fact is, summer tires become hard as ice when it's cold. Winter tires are much softer and designed to cope with the temperature.

Originally Posted by JimD

While I didn't push it this morning I did corner hard enough to get the wife's attention with the temperature around 30 using the summer Michelin's and it held it just fine. I don't plan to play racer but I wouldn't with different tires either. Cold weather driving is more survival than fun to me and the street is a poor place to find limits regardless.

With respect to why different manufacturers use different tread patterns I think it is a different balance of the various factors. If you optimize snow traction, you give away dry traction and possibly wet traction too. Plus you do something to noise. Wear rate may also be affected by tread pattern.

I'm not saying there is no difference in compound, there is, just that it is a secondary factor IMHO. The main reason snow tires work so much better in snow is they throw the snow out of the tread. Tires that do this really well dig into the snow maximizing the available traction. My summer tires would be terrible at this. All season better. Good snows best.

Jim

[Overpar56]

Summer tires below 45F is dangerous. Crap, even my no-torque Miata will drift on dry pavement below 40. Add a bit of moisture and it's all over the place.

I tried to get by on Bridgestone RE 050's on my RX 8 one winter. It was scary. I got the 135i in October and put winters on in November. $1000 for winters was worth it

Now if I lived in SC and the temps rarely dropped below 40 in the AM I'd probably won't bother. I never had winter tires when I lived in SoCal and we dropped into the low 40s most winter nights.

[TheSt|G]

Originally Posted by JimD

While I didn't push it this morning I did corner hard enough to get the wife's attention with the temperature around 30 using the summer Michelin's and it held it just fine. I don't plan to play racer but I wouldn't with different tires either. Cold weather driving is more survival than fun to me and the street is a poor place to find limits regardless.
Jim

That's an incredibly short sighted view of grip.

Just because you chose not to push the tires in a fun way doesn't mean you won't be required to find the limits of their grip when a kid unexpectedly runs out in front of the car. Summer tires will have significantly worse stopping distances and turning abilities in the cold. Running them in such conditions is reckless and irresponsible. Get caught out in the snow and you will be even more up a creek.

Originally Posted by Overpar56

Summer tires below 45F is dangerous. Crap, even my no-torque Miata will drift on dry pavement below 40. Add a bit of moisture and it's all over the place.

I tried to get by on Bridgestone RE 050's on my RX 8 one winter. It was scary. I got the 135i in October and put winters on in November. $1000 for winters was worth it

All of this.

[JimD]

While I have not pushed the cornering limits I had somebody stop unexpectedly in front of me and my car stopped normally - quite quickly. We were in the teens again this morning and I again drove the bimmer. It's tire pressure is appropriate and it handles just fine. There is definitely no activation of the stability control or ABS occurring so no signs of limited traction - with temperatures in the teens.

I don't know what to say about those that report different experiences. I wonder if there was not another causal factor (like air pressure which is why I mentioned it).

I didn't drive the bimmer, by the way, to prove anything, I drove it because it was in the garage and the SUV was sitting out. My wife and I didn't want to deal with a car interior in the teens admittedly for only a few minutes.

I have no doubt my braking differences are longer than at higher temperatures but I don't know if my distances are longer or shorter than your snow tires both on dry pavement. I realize I am in the minority here but I do not believe summer tires in the winter are hazardous as long as the roads are dry. I've never seen a test where they drew that conclusion. My experience indicates they work fine. Here is a test report by Edmunds where they conclude that summer tires work well year around as long as you can avoid snow:

http://www.edmunds.com/car-reviews/f...vs-summer.html

They don't comment on the temperature of their testing and it was AZ and CA but the summers out braked the other tires on wet and dry conditions. If it was cold, they proved my point but I am not sure that was the case. In any case they flatly state that snow is the only real issue with summer tires. I have no plans to use my bimmer in snow.

[TheSt|G]

Cold snow conditions and cold wet conditions. Massive difference:

[TheSt|G]

Dry is worse as well, and thinking you will only ever encounter dry conditions is wishful thinking.

[alexmtl_135i]

The article you quote tested the tires in the dry in "Fontana, California". This was probably far from cold conditions... They tested dry, wet and snow in 3 different places.

Here you have a much more detailed article:
http://www.edmunds.com/car-reviews/f...ter-tires.html

----
The type of rubber itself is also important. Winter tires are built using rubber compounds that remain soft even in extremely low temperatures. On the other hand, most summer and all-season tires use rubber compounds that harden at low temperatures, resulting in compromised cold-weather performance.

"The hardness of these tires at lower temperatures means they no longer conform to the surface of the road," says Joerg Burfien, director of research and development for Continental Tire. "This leads directly to reduced grip on the road and a much-reduced overall performance — mileage, braking distances, cornering, handling, etc. — ranging from 20-25 percent."

----

Originally Posted by JimD

While I have not pushed the cornering limits I had somebody stop unexpectedly in front of me and my car stopped normally - quite quickly. We were in the teens again this morning and I again drove the bimmer. It's tire pressure is appropriate and it handles just fine. There is definitely no activation of the stability control or ABS occurring so no signs of limited traction - with temperatures in the teens.

I don't know what to say about those that report different experiences. I wonder if there was not another causal factor (like air pressure which is why I mentioned it).

I didn't drive the bimmer, by the way, to prove anything, I drove it because it was in the garage and the SUV was sitting out. My wife and I didn't want to deal with a car interior in the teens admittedly for only a few minutes.

I have no doubt my braking differences are longer than at higher temperatures but I don't know if my distances are longer or shorter than your snow tires both on dry pavement. I realize I am in the minority here but I do not believe summer tires in the winter are hazardous as long as the roads are dry. I've never seen a test where they drew that conclusion. My experience indicates they work fine. Here is a test report by Edmunds where they conclude that summer tires work well year around as long as you can avoid snow:

http://www.edmunds.com/car-reviews/f...vs-summer.html

They don't comment on the temperature of their testing and it was AZ and CA but the summers out braked the other tires on wet and dry conditions. If it was cold, they proved my point but I am not sure that was the case. In any case they flatly state that snow is the only real issue with summer tires. I have no plans to use my bimmer in snow.

[TheSt|G]

^^^

Precisely.

[Kgolf31]

Here is my testing with summer tires.

Outside air temp was around 40 degrees.

If you can't even put power down in a FRS, and almost spin going from 1st to 2nd gear on grippy RS3s, then clearly weather temperature is a factor.

[TheSt|G]

Originally Posted by Kgolf31

Here is my testing with summer tires.

Outside air temp was around 40 degrees.

If you can't even put power down in a FRS, and almost spin going from 1st to 2nd gear on grippy RS3s, then clearly weather temperature is a factor.

But all that power!

[XHRL]

I'm on Conti DWS (not really a snow tire, but we don't get too much snow in Philly)
I hold the DSC button until traction control is off when driving in deep snow, tires spin at first and it grips immediately and I'm driving with a decent amount of control

car drives up hills nicely as well