FWD vs RWD for snow and ice

[Isaac Zachary]

Originally Posted by Autobahnschleicher

Over-/understeer is not just about the weight ballance of the vehicle.
If it was, my car would oversteer all the time, yet it normaly understeers slightly.
And no, FWD isn't safe from oversteer either, many FWD cars are prone to liftoff-oversteer.
Especialy ones with twist-beam rear suspension.

Ya, I've heard of suspension affecting under/over-steer. So that kind of information is helpful.

[cRiPpLe_rOoStEr]

Originally Posted by freebeard

I was actually mentioning newer models, which are still available. Well, hadn't it been for the Chicken Tax, maybe an attempt to sent some to the U.S. wouldn't be out of question. Nowadays it could be an option instead of those Chinese mini trucks imported for (supposedly) off-road use only.

[Varn]

If driving on mud or snow like we have here and only have 2wd, you can get up steeper hills with power over the tires that have 60+% of the weight. Winter driving is more than all out speed.

With the traction down to 5% of dry, having the traction on the front is the way to go. If you are cornering reducing throttle will tighten up the turn. Using a handbrake can both slow the vehicle and induce oversteer.

I have owned vehicles for the last 55 years and have a number of years of racing motorcycles both off-road and road racing, I run snow tires on all four wheels of all of my vehicles all year round. I can deal with reduced traction in the dry a lot easier than having the traction go from 10% to 1% in the mud, ice or snow.

Street driving or riding is not racing.

[classicalgas]

AWD with a 50/50 weight distribution and a high polar moment is the ideal, but tends to get you gong too fast for conditions,since stopping is still the biggest problem.

[Isaac Zachary]

Originally Posted by Varn

If driving on mud or snow like we have here and only have 2wd, you can get up steeper hills with power over the tires that have 60+% of the weight. Winter driving is more than all out speed.

RWD can help with getting up steeper hills. But how often do you find a super steep hill road in places where it gets snowy and icy every winter? And even if you do find one that requires you to have at least RWD, what are the chances you're going to want to come back down that same road without something like tire chains? And of course it's better to come down a steep hill with tire chains on the front. So are you going to get out and put chains on the front of your RWD car? Or just put chains on your FWD car and make it up and back down just fine?

Originally Posted by classicalgas

AWD with a 50/50 weight distribution and a high polar moment is the ideal, but tends to get you gong too fast for conditions,since stopping is still the biggest problem.

Yes, getting you going too fast is a problem for a lot of folks. I try to drive as slow as I would in a 2WD when driving an AWD. But I know a lot of people who go buy AWD and then complain that the brakes stop working. It's not the brakes it's that now they don't understand that they have double the traction while accelerating but the same traction while braking, making places feel less slick while accelerating than they really are.

Of course the same thing happens to people driving on the highway without any stops. In town you're constantly stopping and going, which allows 2WD, especially FWD, to remind you it's slick out. But going down a highway people tend to keep going faster, and faster, and faster, even in 2WD until they have to stop. They they ask themselves "Why am I driving so fast!? Why am I driving so fast!?" as the come sliding to a stop (or crash, whichever comes first). This is why you're supposed to go 2/3 the speed limit or slower on ice and snow. If the road is white and the speed limit is 60, you should be going 40 even though it might feel slow.

But knowing how to drive for the conditions in an AWD is the best, except for the cost. AWD costs more new and tends to keep its value higher than 2WD. And once they're as old and cheap as the old 2WD's then there's more parts that are going wrong and so more costly to keep fixed. Not to mention worse fuel mileage. This makes those of us with smaller wallets to tend to drive a 2WD even in places where richer people wouldn't even think of driving a 2WD.

[classicalgas]

I was surprised at how good the mileage was on our old subaru forester.Must have been from about 2004, before they got so huge, but after they raised the ride height.I could easily hit 40 mpg on the highway, often at over 70 mph.Subies aren't especially expensive, at least around here, where they are common. Upkeep costs weren't bad for a 15 year old car, we finally sold it after someone rear ended my wife and kids hard enough to make the rear doors bind up. Subaru has been doing full time 4wd longer than anyone, so far as I know (since the70's?) maybe they are better at it than most?

[Varn]

The true measure of any winter vehicle is can it get through reliably.

We have a half a dozen steep hills to the nearest paved road, that my rwd vehicles can not get up without dramatics when conditions are bad without chains. they have snow tires on all 4 wheels. This ain't suburbia. Our postman uses studded tires on his Jeep.

Half the snows here don't get any road tender service. We get a lot of ice.

I bought a new GMC Syclone when they came out in 91 and found out very quickly that awd doesn't help with handling or braking, the smooth power delivery leads to a false sense of security.

I tend to put narrower tires on my vehicles for better traction. Tends to reduce hydroplaning.

One of our vehicles has anti lock brakes. I hate them they increase stopping distances in bad weather. About all they do is to keep the vehicle going straight.

Originally Posted by Isaac Zachary

RWD can help with getting up steeper hills. But how often do you find a super steep hill road in places where it gets snowy and icy every winter? And even if you do find one that requires you to have at least RWD, what are the chances you're going to want to come back down that same road without something like tire chains? And of course it's better to come down a steep hill with tire chains on the front. So are you going to get out and put chains on the front of your RWD car? Or just put chains on your FWD car and make it up and back down just fine?



Yes, getting you going too fast is a problem for a lot of folks. I try to drive as slow as I would in a 2WD when driving an AWD. But I know a lot of people who go buy AWD and then complain that the brakes stop working. It's not the brakes it's that now they don't understand that they have double the traction while accelerating but the same traction while braking, making places feel less slick while accelerating than they really are.

Of course the same thing happens to people driving on the highway without any stops. In town you're constantly stopping and going, which allows 2WD, especially FWD, to remind you it's slick out. But going down a highway people tend to keep going faster, and faster, and faster, even in 2WD until they have to stop. They they ask themselves "Why am I driving so fast!? Why am I driving so fast!?" as the come sliding to a stop (or crash, whichever comes first). This is why you're supposed to go 2/3 the speed limit or slower on ice and snow. If the road is white and the speed limit is 60, you should be going 40 even though it might feel slow.

But knowing how to drive for the conditions in an AWD is the best, except for the cost. AWD costs more new and tends to keep its value higher than 2WD. And once they're as old and cheap as the old 2WD's then there's more parts that are going wrong and so more costly to keep fixed. Not to mention worse fuel mileage. This makes those of us with smaller wallets to tend to drive a 2WD even in places where richer people wouldn't even think of driving a 2WD.

[JSH]

Originally Posted by Varn

One of our vehicles has anti lock brakes. I hate them they increase stopping distances in bad weather. About all they do is to keep the vehicle going straight.

ABS has changed a lot since 2005. The big change was in 2012 when stability control become mandatory. I'd give a modern system a chance before writing of ABS.

Early ABS was single channel. All it did was modulate the brakes on and off much faster than a human could pump the brake pedal. However, if any wheel lost traction and locked the ABS valve cut brake pressure to all 4 wheels.

Then we got dual channel ABS. The front and rear brakes were modulated independently. This was a big upgrade - especially for vehicles like unloaded trucks and vans where the rear end is light to begin with before weight transfer under braking.

Then we got 4 channel ABS (in conjunction with stability control) Each wheel is monitored and modulated independently.

Modern ABS systems also have accelerators and gyroscopes in additional to wheel speed sensors so the computer has a lot more information to work with and much faster processing speeds.

2006 Toyota Tundra ABS Valve


2012 Toyota Tundra ABS Valve

[Isaac Zachary]

Originally Posted by classicalgas

I was surprised at how good the mileage was on our old subaru forester.Must have been from about 2004, before they got so huge, but after they raised the ride height.I could easily hit 40 mpg on the highway, often at over 70 mph.Subies aren't especially expensive, at least around here, where they are common. Upkeep costs weren't bad for a 15 year old car, we finally sold it after someone rear ended my wife and kids hard enough to make the rear doors bind up. Subaru has been doing full time 4wd longer than anyone, so far as I know (since the70's?) maybe they are better at it than most?

The main problem is the initial cost. Looking on Autotrader there's only two Subarus that are under $3,000 within a 200 mile radius of where I live. And they're so old with so many miles I'm not sure if I want to deal with them. From there, I can get a 20 year old Subaru for nearly $4,000, and they go up from there. I've bought 3 different FWD cars in my lifetime that were $600 or cheaper and ran just fine and were in a 5 mile radius of where I live. Well, at least two did, the $300 Prius needed a battery module replaced and a wheel bearing. But the VW Golf was a beast that seemed immortal except for cheap aftermarket CV joint problems.

I find it hard to believe you got 40mpg in your Subaru, especially at 70mph. I have a hard time getting 40mpg in my Toyota Hybrids. And while I can get a bit more than 40mpg at 55-65mph, I can't seem to be able to get more than 35mpg at 75mph.

[cRiPpLe_rOoStEr]

This beauty is a 4WD, yet the FWD versions outnumber it and are often pointed out to be much more reliable on the long run.