i know this is a stupid question, but which is better for driving in snow? front wheel drive or all wheel drive?
Front wheel drive is the engine is in the front, rear wheel if the engine is in the back. Personally I would rather have the engine in the front, and FWD. Seems pulling would offer more control than pushing, no?
All wheel drive and opposed to 4wd refers mainly to the type of drive system used to drive the rear wheels. Basically there is no direct mechanical link betweet the rear wheels and the engine. Power is usually transmitted through fluid to the rear.
That said - awd rulls - I have been in many icy, snowy roads where other cars were stuck - rocking back and forth to get out of the hotel parking lot or whatever. I get in and go - no traction trouble.
[Moderator Hat ON]
This hopefully has a factual answer, so I am moving it to General Questions.
[Moderator Hat OFF]
Actually, most rear wheel drive cars have the engine in the front. It’s connected to the rear differential by a drive shaft.
I don’t know the (factual) answer to this question; but, yes – it seems that pulling would be more efficient than pushing. (Note that most cars being built today have front wheel drive.)
FWD vs. 4WD? I think that 4WD would be better for driving in snow. I haven’t taken the Cherokee into snow yet (at least none that’s been on the groud), but I have taken it offroad in the mud. There is more control with 4WD than with RWD. I used to drive a Chevy Sprint Metro (Geo Metro). Its light weight and FWD allowed me to make it up to the ski area without putting on chains. But I can’t make a direct comparison between FWD and 4WD.
Your differential type has some impact on this as well. A front-wheel drive car with a limited slip differential might actually do better at times than a 4wd car with open differentials all around.
Generally, in most applications, a MODERN AWD setup is superior to just about anything out there…
FWD is better than RWD only because the weight of the engine over the front wheels adds grip. VW Bugs are RWD and Rear Engine, so they get some traction too.
But, while there might be an exception to the rule out there (and I’d like to see it), AWD is far superior to 4WD and FWD.
4WD doesn’t move power around…the modern AWD setup moves power around and is often linked to a “traction control” set up that prevents you from applying too much power to ANY wheel
FWD with limited slip is nice, but AWD with traction control and ABS is damn hard to top.
Don’t my bubble and tell my that the VW Bug is now FWD and front engine…I said Beetle…the new car is referred to as The New Beetle.
-just anticiapting nitpicking.
Oh, and here’s a nitpick: AWD and 4WD are distinctly different…whereas AWD is dynamic and 4WD is static in the setup more-or-less.
In general FWD is better than RWD, especialy in curves. There are however occasions where RWD is better! When going up a steep hill with FWD, the weight on the front wheels decreases, and they may start slipping. One solution is to reverse up the hill, as that puts more weight on the front weels (now behind/under the car!)
(I have nothing to add to the AWD/4WD debate)
Philster is right, AWD is the best set-up for driving in snow. I don’t know that I’d consider it FAR superior to 4WD, but it’s certainly more versatile and eliminates any concerns of having 4WD engaged in inappropriate circumstances.
In comparing FWD to RWD (ignoring rear engine layouts), FWD is certainly better for being able to get going in snow. There are some questions about its handling in certain circumstances–I recall hearing about FWD cars leaving the road more often than RWD ones when descending slick mountain roads.
Generally, AWD systems offer the best power-to-the road application for any type of driving surface.
I’ve had FWD, RWD, and 4WD, and driven all on snow extensively. While I’ve never driven an AWD car, my guess is I can class it with 4WD as the best on snow.
However, there’s been a fair amount of discussion about the relative benefits of front and rear wheel drive, almost all of which has been about weight distribution. There is more to it than that. Weight distribution helps, but when driving on heavy snow and ice, your wheels will inevitably spin. I’ve found that front wheel drive is much easier to control in that situation than rear wheel drive, because the drive wheels are doing the steering. With front wheel drive, if the car drifts to the right, you turn the wheels to the left, and the spinning wheels pull you in the direction you turned the wheels. As a matter of fact, in the really thick deep snow, at low speeds, I’ve found that it’s often easier to control a front wheel drive car when the tires are spinning. (Remember, I said LOW speeds - less than 20 MPH.) You can, to a certain extent, steer a rear wheel drive car in the same way, but you have to do so by skidding the whole car to get the drive wheels pointed in the same direction. It’s a lot easier to do at low speeds with front wheel drive, where you don’t have to pivot the entire mass of the car to change the direction the drive wheels are pointing.
As for front wheel drive cars skidding out of control on downhill roads, I can kind of see what you mean. However, this usually happens to drivers who are used to rear wheel drive cars, and expect a front wheel drive car to handle the same way in the same circumstances. If you are going fast into a corner, and the drive wheels spin, front wheel drive and rear wheel drive cars are going to do two very different things. In a rear wheel drive car, the back end is going to start to slide to the outside of the corner, effectively pointing the car towards the inside of the turn. A carefully applied throttle in this circumstance can actually push you through the corner. When the drive wheels spin on a front wheel drive car that’s going fast into a corner. the front wheels no longer are able to guide the car into the corner, so the car tends to exit the arc on a tangent. As long as you don’t try to throttle-steer a front wheel drive car through a corner at speed, you’re fine.
In short (I know, too late!) I’ve found front wheel drive cars to handle heavy snow at lower speeds much better than rear wheel drive cars. This is great when you’re trying to get from your driveway down an unplowed street to one of the main roads which has been cleared. Both front and rear wheel drive cars do fine under normal circumstances. And, of course rear wheel drive cars do better when you’re pushing the car a bit on dry pavement, especially on twisty roads.
FWD issue:
For handling purposes, FWD in the snow and turning will be prone to major doses of understeer…which is a condition where the front tires lose traction before the rear tires lose traction.
Front tires on FWD get overloaded because they are cornering a larger load AND dealing with power from the engine.
Understeer is like steering while your car plows away from the direction the tires are pointing…all the while the rear tires are doing fine…the car sort of pushes off the road and off the intended drive line.
RWD cars will do the more classic spinout because the rear wheels lose traction quicker when the differentials weight is back there along with the added power.
That being said, a FWD car can be tuned to oversteer, even though i’s tendency is to understeer and a RWD car can be tuned to understeer, even though it tends to be an oversteerer.
4wd provides power to all the wheels in a predefined amount. In 4wd, if a wheel slips, power is applied anyway. So, you have four wheels trying to get traction at four corners of the car, which makes for pretty good odds that one or two will grip enough to keep you moving.
AWD is dynamic: Wheel slips? power is then exerted elswhere, dynamically…fluidly…so there is not a calcualtion that says it happend 47,000 times a second…it’s dynamic. That makes AWD a hard thing to beat…it’s dynamic. It is a huge leap away from 4wd. 4wd is simply a way of improving one’s odd in the tires search for grip. AWD is a way of dynamically moving power around to wheels as they slip, slip less, more, alot, full slip…etc etc…
AWD also is usefull on dry and damp surfaces, where 4wd and it’s locked axels is actually DANGEROUS.
AWD and 4WD aren’t as clear-cut as that, Philster. AWD and 4WD can mean many different drive systems, depending on the manufacturer. The definitions (if they were ever precise) have become so blurred that they’re no more than marketing terms now. As usual, How Stuff Works has the answers.
Kamandi, I’m going to stand on what I said.
‘How stuff works’ is a cute site, though.
We’ll use MY definitions…
4wd: wheels all powered via locked differential. Can be turned off/on
AWD: dynamic transfer of power to all wheels…continuously engaged system…no “selector knobs”
Sure, Honda calls their AWD “real time 4wd”, but they can kiss my ass because it’s essentially “AWD”.
Let’s not confuse the issue any further. You essentially shouldn’t confuse 4wd (like in my Dogge pickup) with the sophisticated AWD systems by Subaru, Audi, Honda, etc etc etc.
GENERALLY (which means I ackknowledge nitpickers like you in ADVANCE so as to not have to hear from you)…GENERALLY, AWD and 4WD differs as I’ve explained it.
Essentially (disclaimer word again) AWD kicks FWD ass…and we don’t need people coming in here talking about 4WD and screwing it all up, because using 4WD physics is insulting to the dynamic platform that is modern AWD.
Jesus H. Christ, Kamandi, How Stuff Works didn’t enlighten me!
I swear, I love these boards and hate them at the same time!
Kamandi, maybe YOU should read How Stuff Works.
Sorry, Mods, be gald to hack it out in the pit.
Calm down, Philster. This is General Questions, not IMHO. Since you never attributed any of your statements, and I considered some of your comments overly generalised, I thought the discussion needed a dose of fact from an acknowledged source. You may be an expert on all things AWD, but some reading this thread might actually learn soemthing from How Stuff Works. Sorry to hurt your delicate feelings.
Why? Let’s use the real definitions, backed up with cites. You may call it nitpicking, I call it getting the facts straight. This is GQ. If you don’t like it, head on over to MPSIMS.
Not necessarily true. My Jeep Liberty is equipped with two systems that Jeep calls “4WD”. In “Command-Trac”, 4HI locks only the center differential, and must be selected by the driver. the front and rear diffs are open. (A limited slip rear diff is an option.) “Selec-Trac” is a full time four wheel drive system, dynamically tranferring torque to the wheels that need it. Sound familiar? (4LO in both systems does indeed lock all three differentials, and acts as you describe.)
That’s just my point. The terms are not rigorously defined. You can’t waltz into GQ and apply your own pet definitions on them.
I submit that AWD and 4WD are interchangeable terms for the same basic thing: applying engine torque to all of a vehicle’s wheels. A wide range of methods can be used to do this, with varying results. Determining which is most effective is a discussion best left to IMHO.
I’m assuming that everyone already realizes that probably 80%+ of the handling ability of different types of vehicle on snow or ice or any crappy terrain depend on the skill of the driver. I’ve seen it time and time again where someone goes and gets the fanciest “x-WD-anti-lock-thingamajig-traction-control-siberian special” vehicle and can’t even get out of the driveway 'cause they simply have no skill.
Many years ago my dad made it up an icy hill in a 50’s RWD Chev in Calgary that the city’s sanding trucks couldn’t even get up. I know that different types of vehicles in themselves have better handling abilities in snow, but I can’t say which is best since I’ve never found it neccesary to shop around for a snow-car and compare. I’ve driven (so far) all RWD vehicles raning from chevettes to suberbans in the snow sans problems; in most cases you’re better off practicing in whatever vehicle you have and learning how to use it effectivly than searching for a vehicle to make up for the short-comings of driver ability.
kamandi, sorry for the tone. I got too jazzed up about all that.
No sweat.