RWD are harder to drive in snow and slippery conditions.
Snow tires makes more of a difference than being FWD or RWD in heavy conditions is the real truth here.
Snow tires are essential. I went out one day on Dec 31 without snows and made it about 300 feet from my driveway before I went in the ditch and rolled my car.
Circa 2008 I drove a FR Buick for a few weeks that had traction control and I was impressed with how it handled in the snow.
FR is front engine, rear wheel drive
The engine can be placed front (in front of the front axle), mid-engine (between the axles), or rear over/behind the rear axle.
It affects weight distribution and therefore the vehicle’s handling.
And snow tires is what makes a difference, true, but you can mount them on any car and same thing for traction control. So a same age AWD with snow tires drives better than a RWD with snow tires, specially if you come from a stop on an upwards icy road.
AWD is better than FWD or RWD, yes, but driving in the winter without snow tires.
AWD matters exactly 0 when emergency braking and little as long as you aren't driving flat and not accelerating.
Snow tyres help when accelerating, braking, driving straight forward and through curves, uphill and downhill.
There is a reason why snow tires are mandatory here and AWD is not.
Correct. All cars, whether they are FWD, RWD, or AWD are All-Wheel-Brake. The most important aspect of stopping safely are your tires.
Yeah. They do.
I've driven pretty much every combination of FWD, RWD, 4WD, and AWD, with and without snow tires, in a variety of winter conditions. The "other tires" were regular all seasons, not high performance summer tires or anything.
RWD with all seasons is really bad in snow, and mine generally didn't leave the parking lot in winter, because it simply couldn't. When you can start it, put it in reverse, let the clutch out, get out, and watch a wheel turning without the car having moved an inch, it's not a good day to take that car.
FWD with all seasons is better, because there's typically more weight over the drive wheels, but they're not great in snow.
4WD/AWD with all seasons (I lump them together because while there are some differences, it doesn't matter in typical snow) is far better, and hysterically fun to drive (drift all the wide corners), but it's still somewhat tricky in snow. And, yes, you do get better braking with 4WD, because the front brakes slow the rear wheels too (most of the braking force is on the front wheels, especially at initial application). The catch is that when you lock the wheels, you lock all four and have zero guidance, vs just locking the front and at least continuing mostly straight (or, usually, whatever the local downhill is).
FWD or RWD with snow tires is, by far, better than AWD with all seasons.
And then AWD/4WD with snow tires is just a case of "What snow?"
Why is it so hard to believe that a product that advertises 30-50% improvement in traction results in a lesser improvement than doubling the area over which tractive force is applied?
I used to drink the snow tire kool-aid until I bought a set for the FWD car of and realized that better straight line stopping distance and cornering ability don't actually help you because being able to controllably put power to the ground is still the bottleneck in the "is it reasonable to drive in these conditions" equation by a mile and while they help they are nowhere near a replacement for doubling the contact patch that force goes through.
Sure, they get me a little bit of margin to be an idiot and come into turns too hot or stop short but I wasn't really doing that stuff in the snow anyway so the benefit is lost on me (and people adapt their driving style to the performance they have available so how big is the benefit really?) and they still don't make the FWD car climb my damn street like the AWD car does so I don't buy them anymore. I keep chains in the trunk for the really bad days.
The FWD/RWD nit picking is mostly irrelevant IMO because any fundamental difference is far less than the vehicle to vehicle difference within or outside a given category. Better handling in the dry more or less directly leads to better handling of the same type in the snow. A RWD box truck will out hill climb a FWD minivan but the latter will out corner the former and a Miata and hot FWD hatch will be better than both at everything.
> better straight line stopping distance and cornering ability don't actually help you because being able to controllably put power to the ground is still the bottleneck in the "is it reasonable to drive in these conditions" equation
I take this to mean the answer is no. I drive in serious winter conditions, and AWD with winter tires is great, but it doesn't matter how many wheels are applying traction when you slide into a ditch.
The reduced ability to stop and turn has lead to in my snow driving experience, far, far fewer "that could have easily gone worse" situations than a lack of ability to gracefully put power to the ground.
I don't get why everyone obsesses over stopping and turning and shills snow tires. There's a reason that everyone and their brother buys an AWD vehicle and far fewer people buy snow tires. Everyone(TM) can't be wrong.
What I want you to tell me is why I should prioritize braking and steering if they're not the bottlenecks I encounter when driving in the snow.
Most accidents are caused by failure to stop and failure to turn, not failure to accelerate.
> There's a reason that everyone and their brother buys an AWD vehicle and far fewer people buy snow tires.
You clearly live in a very different place than me - very few passenger vehicles are available with AWD (subarus, trucks, some SUVs). But everyone has snow tires.
> What I want you to tell me is why I should prioritize braking and steering if they're not the bottlenecks I encounter when driving in the snow
Great for you? Again, you clearly live in a place with very different conditions than I do. What about the conditions make it so that you can't accelerate, but you can turn or brake just fine?
I regularly drive in conditions in my damned Camaro where the only other vehicles on the road are trucks, with some of them not being on the road anymore.
I agree that tread depth is massively important in the slushy conditions that commutes in the snow devolve into. You need that depth to provide a path for the "thick water" to GTFO so you're not hydroplaning on slush.
A FWD with snow tires or chains will almost certainly have better snow/ice handling than a RWD with snow tires or chains, by the simple virtue of the drive axle being steerable.
If you've played Kerbal Space Program or a similar spaceflight simulator + rocket designer, then the reasoning here should be pretty intuitive: if you can only apply thrust to the reverse, and don't have reaction wheels, then in space you have no ability to steer under your own control. You need to be able to point thrust to the sides if you want to be able to turn (or stop turning).
Same deal on an icy road. RWD means all your thrust is pointed backwards; FWD means you can point your thrust to the sides and control your car's orientation. Having both FWD and RWD (i.e. AWD or 4WD) is even better; sure, it constrains the overall thrust angles, but you also get more of it - which means better control when you're driving on a surface that ain't flat.
This ain't just theoretical; it's something I've repeatedly observed every winter here in the Reno/Tahoe area.
Is that a virtue? it makes steering tougher.
The actual virtue is the weight of the motor over the front wheels (coefficient of friction * basically weight above tires)
Not in my experience it doesn't. In icy or otherwise low-friction conditions, the steerable wheels being powered makes correcting for understeer and oversteer much easier than if they're unpowered - specifically because, per above, you can readily accelerate in directions other than forward/reverse, allowing you to orient the car even when sliding out. You can't rely on the tires' lateral friction to help you steer; a tire at an angle on ice will just slide with the rest of the car, and needs to be spinning to apply any force on said car other than forward.
The catch, though, is that you have to be willing to accelerate at the very moment your brain would otherwise panic and tell your feet to hit the brakes. Hitting the brakes will make things considerably worse by stopping the spin on your tires (especially the fronts, which are the very tires for which spinning is absolutely essential for steering control).
(In snow, this is a little bit less severe; the deeper the snow, the more pushback on the sides of the steering tires when at an angle, which helps a little bit with steering - but not nearly as much as on a dry road, thus still necessitating being able to accelerate with those tires)
> The actual virtue is the weight of the motor over the front wheels (coefficient of friction * basically weight above tires)
This also helps, but not nearly as much as the front wheels being able to accelerate in the direction they're pointed.
The trick, in my experience, is to learn how to get into a tailspin and do donuts. Unplowed parking lots are best for this. When you're familiar enough with the vehicle to do controlled tricks, you're just about prepared for an emergency. I've never owned a FWD car through a snowy winter; it's really down to what you're experienced with.
You only have so much traction to accelerate, brake, and steer. Sharing them on the same wheels seems objectively worse at the limits to me, except in the sense that every car is all wheel stop.
I think some of the safety issues associated to RWD were problems of the days where they were more common. Trucks need weight in the back, we know that, and winter tires are way better now.
You have to learn how the car handles when it's not an emergency to know what to do in a panic. I toss every car I own around in a snowy parking lot at least once so I know what it'll do. This seems insane to a lot of people I've talked to.
That said, I think understeer is safer and more predictable in most situations for people who use their cars as a transportation appliance. You point and shoot, so to speak. Most people aren't driving at the limits.
Strictly speaking, if your car is out of control, you're driving past the limits. The whole point of the parking lot exercise is to learn where the limit is. I drive like a granny, but prepare for the worst. And I've learned over the years to avoid the first day of snow in a season.
You've still got one control working in the rear: brakes. The understeer characteristics of a FWD car are very easy and intuitive to recover from. If someone can't manage traction in an FWD understeer condition, they almost certainly lack the skills to manage oversteer.
This might be true when discussing snap over-steer and throttle induced under-steer on a track but is a complete lie for snow driving where most drivers will just keep steering harder in response to under-steer which is not productive and you don't have enough traction for lifting and braking to induce much extra weight on the front.
That's my point. Make the wrong correction in RWD car and you end up oversteering beyond 90 degrees in an unrecoverable spin. The failure modes of FWD understeer in the snow are all recoverable.
You're making one of those textbook correct but reality wrong statements that clipboard warriors love.
Sure, you can recover from under-steer but if you're already doing the wrong thing and pointing the wheel where you want the car to go you almost certainly won't.
With over-steer if you do the "natural" thing and steer the wheels toward where you want the car to point at least you have a chance. Sure many people might flub it but that's a heck of a lot better than the "no chance" you get if you react the same way to under-steer. Also, if you do over-correct the over-correction may very well not be as severe as the initial over-steer giving you a better chance to get it right the second time.
Sure, under-steer is theoretically recoverable and with over-steer you can theoretically spin or slide backwards but in reality in "on the street" situations (i.e. not what you see someone doing on an old taxiway in a training video) 99.9% of the time you'll have hit something long before either happens.
Edit: Since I'm apparently so wrong anyone care to explain? Or is it just "sideways bad because smart man with vest and clipboard say so".
That is the understated safety factor of understeer, but people prefer to think in terms of never doing mistakes instead that in terms of overall safety
To be fair, they probably wouldn't get stuck in my driveway but I can stop a hell of a lot quicker and turn if necessary. I also find controlling a near spinout to be more intuitive on a RWD vehicle than a FWD one, but that might be just because my first car was RWD as well.
I’d tell you about my tactics for going around corners fast in a FF car but I’d get downvoted…
Back in the days this could also be used for performance reasons, to keep the turbo on, preventing it from needing to kick in again upon re-acceleration out of of the corner (back then turbo lag was huge and the "kick" was hard to control).
This technique was known to be very harsh on the engine but some races pilots would do it anyway.
FR = Rear-wheel drive
For anyone else who couldn't puzzle out WTF those meant, I'll save you looking it up.
FF = front engine, front wheel drive
FR = front engine, rear wheel drive
RR = rear engine, rear wheel drive
MR = mid engine, rear wheel drive
FF 4WS
FR 4WS
4WS is for «four wheel steering» (the emphasis is on «steering», not «driving») where – depending on the travelling speed – the rear pair of wheels turns either in the direction opposite to the front wheels (≤ 20 kmh) or in the same direction (≥ 20 kmh). The former makes the parking easier and reduces a turnaround circle. The latter makes the car look moving sideways when going around a bend or disappearing from its lane and emerging in the neighbouring lane during the lane change. 4WS also handles a bit differently on slippery roads around the bends.
Source: was taught this stuff by someone that won SCCA autocross nationals, as well as a few podiums in rally. Go to any rally event and you'll see plenty of FF cars doing every drift you can imagine through corners.