Icy hill best taken in neutral?

Reading the Christmas Day Seattle Times I was shocked to find that Tom and Ray were in agreement and simultaneously wrong–usually only one of you guys is wrong. Probably you are spending too much time in the garage huddled around the space heater, breathing fumes instead of doing winter driving. Carol wanted to know if her silent farm boy husband was correct about putting the car in neutral going down a critically slick hill. Like many silent husbands, he is absolutely correct. In the case of a two wheel drive car on a very slick surface, the goal is to apply none or equal gentle braking force to all four wheels. Being in neutral or having the clutch disengaged will allow gentle, equal four wheel braking. If you want to prove it to yourself, try driving very slowly down a small critically slick hill with the transmission engaged at idle. Then gently apply the brakes. The free wheels will stop and break traction while the drive wheels will continue to turn. The loss of control is most dramatic if the stopped free wheels are the front ones on a rear wheel drive. For an even more dramatic example of the effect of unequal stopping effect afforded by engine drag in a two wheel drive, go from neutral into drive while descending a critically slick hill. The break in traction will be very entertaining. With four wheel drive, and especially a four wheel with an automatic stability control, this issue of engine drag providing unequal braking force disappears, although the farm boy approach does no harm with four wheel drive. But farm boys are not used to depending on these devices that allow you to drive on critically slick surfaces–even if you’re under the influence of space heater fumes.

Nope, you want to go slowly in gear to maintain control, hopefully avoiding the brakes all together. Worked for me in Anchorage.

I’ve driven down icy hills (in my driveway) and, especially in the first minutes of driving, putting it in neutral and slowly and gently letting the car down the hill was the best. The cold weather high idle pushed the car down, making a tension in the effort to keep speed down and retain control. There were times when the car would start to slide from a dead stop, and pumping the brakes while gently trying to retain directional control when the wheels were turning was the best choice. Having the engine pushing the car down the hill at the same time made things worse.

True, in that particular situation. But in general, if someone’s driving along and comes to an icy hill it’s better to leave it in a low gear. Coasting in neutral can result in rapid speed gain, requiring braking that could lead to a skid.

Sorry to disagree. 4wheel drives are very forgiving with engine braking on ALMOST all conditions, except…glare ice. Then and only then, using the abs, works best while in neutral. Leaving it in low gear is disastrous with all drive trains if engine brake is great enough to keep those drive wheels from free wheeling. I have even had to take trucks out of 4 wd as the drag from the front diff, even in neutral as too great…very rare but if you can see your reflection in the road…do it.

Tractors are brutal…with hydro, you even have to accelerate down hill to maintain control as putting them in 2 wd leaves you with no front brakes…and neutral is out in manuals with no synchronizers. Screaming and ramming trees with the bucket is common !

If you don’t have abs, you must continually pump your brakes to balance minimum speed with control. An alternative for the un initiated, is to just leave vehicle in DRIVE and use brakes. But generally, neutral for all trannies. Beware, at very low speeds, your car may disengage the abs, forcing you into the pump and pray mode regardless.

The very worse thing is low range 4 wd. The torque multiplier of low range guarantees loss of control as your last words will be @$;:blush: as you slowly rollover into the nearest ditch.

If Tom and ray and Texases disagree, you have now officially qualified as “flatlanders”. :=) Wentwest, Geezerman…you be fellow mountain men…

I doubt if anyone can give a simple answer to this one.  There are far too many variables.  What works in one car may not work in the next.  Weight distribution. gear ratios how steep the hill is the road conditions (different temperatures of the road surface) type of tyres weight distribution etc. 

What works well for me in central Ohio may work poorly in Washington state. 

I strongly recommend real Winter tyres for a start.  All season tires are a very poor second choice. 

If the car or winter driving is new to you or even if it has just been a year since your last experience with snow and ice, take some time and practice.  Find a nice clear parking lot and see what your car does on ice.  Do the same for snow. 

Drive for safety.  Work to make sure you get home safely, not first. 

If you can’t drive safely due to the conditions, stay where you are. I have ended up sleeping on the floor or sharing a room with new friends when the roads were really bad.

Listed in order of importance:

  1. The driver. (Skill and prudence)

  2. The tyres

  3. Modern anti skid traction control (it is only # 3 because you need to replace the car to get it.)

While not an icy hill, low water crossings where the water flows over the bridge across a creek can become nearly as slick as ice with slime moss. I have learned to pull in the clutch and not touch the brakes when crossing them with my motorcycle.

I install 80 of these on each tire of my tractor in the fall. Not for cars, but if you have a low speed vehicle, including ATVs and such, They work great. For boots, hex head sheet metal screws in dedicated heavy lug boots work very well if you must walk and work over terrain that include glare ice.

Where I grew up in Northern Ontario, we were taught to be able to shift to neutral quickly if we needed to stop under control on slippery ice. This is especially true in the first few minutes of driving when the engine is doing its fast idle thing. We’re talking about carefully applied light braking to avoid locking any wheels. Under light braking on glare ice, the non-powered wheels will lock up before the driven wheels, and there won’t be enough brake force on the driven wheels to overcome the drive from the idling engine.

I believe that this applies with ABS as well - at those low speeds, the ABS would probably:

  1. get confused, or
  2. effectively remove all braking from the non-driven wheels.

Yeah I agree with macfisto. I didn’t hear the question but on glare ice with RWD, I have had the resistence in the rear wheels be enough to cause a slide and need to quickly put it in neutral to free wheel. Also other way around too where you didn’t dare brake and let the rear wheels keep the car from wheeling down the hill too fast. Just depends but I don’t care to repeat those circumstances and there were many others in the ditch not as fortunate as I.

I agree with all except Taxases. With an automatic transmission and the engine trying to go and you trying to stop, it is a lot harder and and more dangerous. In neutral, you have equal stopping power to all 4 wheels.

I generally agree with the above, but: Remember that different cars, different tyres different road conditions can all play into the end result. Even comparing RWD to other RWD or FWD to other FWD etc, they will all be different.

Know your car, and be careful. It is better to be a little late, even a day or two, than to not make it at all.

Good luck, and drive carefully.

Here is the problem I have with Tom and Ray’s advice. I read it and it seems they feel that the motor on the drive wheels does a better job of braking down hill on ice when traction is very limited, then the brakes.

I never knew that the motor could brake all four wheels evenly at once where it can’t power them all evenly when accelerating, even on a 4 wheel drive. I never knew also, that the motor and drive train had abs as well and could automatically modulate the engine braking force to keep vehicle tracking straight and true on ice. Has any ever tried to modulate engine braking on your own ?

Big definite brain cramp(s) for both. Two city dweller flatlanders who probably bounce off parked cars to stop like the rest of the Bostonians. This is one time that “don’t drive like my brother” rings true, both ways.

Good Lord, guys, there are so many different configurations of vehicles, so many different drivetrains, weight distributions, tires sizes and types, and even brake system designs, that I cannot understand how one can suggest that one answer fits all. And that’s not even considering the differences in rates and angles of descent or those off-banked curves in the middle of some of them.

Envision if you will the difference between that Fiat 500 I saw the other day and the Porsche Cararra (with it’s huge stock tires in the rear and its serving-plate sized discs and 50:50 weight distribution) and how differently they both might react to the same technique.

With all due respect Same, this is one instance (down hill on glare ice) where brakes ALWAYS work better then engine braking.

It is expressly true BECAUSE of your statement “so many different configurations of vehicles, so many different drivetrains, weight distributions, tires sizes and types, and even brake system designs”. Brakes are designed to be adaptable to these variables while engine braking is not. One extra person on board can vary the braking requirements that you or you brakes can sense on ice that engine braking can’t.

Engine braking needs adequate traction to match the braking force it provides. Brakes and your foot do just the opposite. The brakes (and/or You) match the braking force to the available traction to retain control. And, it doesn’t matter whether it’s a Carrarra or a Corrolla…you use your brakes first on glare ice.

Respectfully, I cannot agree the one size fits all theory. For example, I was able to maintain better control going down an icy descent by using the engine in my old '89 Toyota pickup. That vehicle had droms in the rear, weighed almost nothing in the rear, and the rear wheels would just lock up and slide if the brakes were applied. Using the engine, I could keep speed from building without sliding any of the wheels.

Actually, years ago I did witness an exact example of the problem that the OP (Geezerman) is stating.

I was pumping gas years ago during a snow storm. The gas station was on a hill. A RWD car, coming down the hill, began to apply the brakes on the snow covered road. The car (with a carburetor) had a high idle.

I saw it going down the hill with the front wheels locked but with the rear wheels still turning. When it finally stopped in someones front yard, we ran over to help. The driver said the high idle kept pushing the car forward and the only way to slow it down was to brake hard enough to cause the front wheels to lock up.

In that scenario, as the OP noted, putting the car in neutral would have avoided the above locked front wheels and loss of steering.

Putting it in neutral takes the drive train out of the equation, making most vehicles pretty similar. Sure, ABS or weight distribution plays a part, but all in all I found going down the hill as slowly as possible with the brakes sort of still holding the wheels was the best. If the brakes were groaning, I was happy.

We’re talking about ice here, not snow. The best solution was when I had a Volvo 245 wagon. I’d keep a steel ash can full of coal ash in the back, along with a garden trowel, and back down the hill with the tailgate open and one of the kids back there would toss out ash on to the ice. It was so windy exhaust wasn’t a problem, and I was going very, very slowly.

the same mountainbike 10:05AMReport

“Good Lord, guys, there are so many different configurations of vehicles, so many different drivetrains, weight distributions, tires sizes and types, and even brake system designs, that I cannot understand how one can suggest that one answer fits all. And that’s not even considering the differences in rates and angles of descent or those off-banked curves in the middle of some of them.”

This is all true, but with the transmission in neutral, all four wheels have equal stopping power. You can let up on the brakes to stop a slide, but the power wheels (front or rear) might still slide if left in gear. However these late model cars don’t have much hold-back in drive (automatic) any more. It’s not like it is in older cars.

The reason you shift into neutral or put in the clutch is to eliminate any engine braking. If the ice is warm enough, say about 30-32 degrees any engine braking will send you into a skid. The poster with a RWD Toyota Hilux that was able to descend an icy hill in gear with his foot off the gas just demonstrated that it wasn’t very slippery. Now if you are in temps of 25 below ( actual temp, not wind chill) or less you can drive almost normally. Really cold ice has pretty good traction.