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Comment by po | Hacker News Reader

> The Model 3 will come with standard rear-wheel drive, with an option for dual-motor all-wheel drive.

It better be fully autonomous if you've ever seen how rear-wheel drive performs in a north-eastern snowstorm. Sure, there's a lot of weight over the back wheels but that sounds crazy to me as the default.

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Eh, you may be defeating your own argument there. The main reason that front-wheel drive is better in slick conditions is more weight over the wheels in the typical front engined car. Rear wheel drive may actually be better if the battery pack is sitting on top of it.

That surprises me, given my extensive experience pushing shopping carts vs pulling them.

Since you don't push your shopping cart by turning the wheels, those intuitions are probably not that helpful. The force you exert on the handle of a shopping cart is not automatically aligned with the direction the cart is facing, meaning it's unstable - any deviation from a direct push generates a turning torque. But the rear wheels of a car are fixed so they will always generate a forward force aligned with the car's axis, never a turning motion (diffs and grip variance across the axle aside).

Not true. I've always driven RWD and have competed in National Amateur racing events with the SCCA (and taught high performance driving techniques at my local club).

I setup my cars with a heafty amount of rear toe-in (1/4"). When the weight transfers left/right or one of the rear wheels hits a bump/hole it will push the car in one direction similar to torquing one side of a shopping cart with your hand.

A RWD setup allows the car to be more efficient with its tires (using one set for turning and one for power vs. one for both). FWD is just seen as safer because most people panic when a car oversteers. As the saying goes among driving enthusiasts: "Oversteer scares passengers, Understeer scares drivers"

So, on the subject of whether rear wheel drive electric cars will have trouble in snow, we've now heard from both a shopping cart driver and a performance racing instructor who configures cars to deliberately amplify rear axle steering effects under cornering. I can't help but think that the reality of driving a Tesla Model 3 in traffic in light snow might be somewhat different to both of those experiences.

On that topic: the selection of the driven wheels probably matters less than people think. The most important factor is the tires. Want winter traction? Buy winter tires.

In modern cars Active Stability Control (ASC) is effective in eliminating oversteer, no matter what the drivetrain setup is. Traction at stop lights would favor RWD when a car has near 50/50 weight distribution (I don't know what the Model 3 is but would guess it's close).

RWD makes the car simpler and with modern ASC is no less safe for the average driver than FWD. I'd guess that traction in a Model 3 would slightly favor RWD but tires matter more.

That depends, RWD is harder to control even if the weight is on the back. Understeer is much safer than oversteer, unless you're a talented driver who knows what they're doing, and oversteer is way more likely in a RWD car.

That's only part of it. The other reason is that on a front wheel drive car, torque is applied in the direction you want to go. On a rear wheel drive car, torque is applied in the direction you are currently going.

A common complain about FWD is understeer though. It's worse with more torque at the front wheels.

Per Musk, the fast torque response and quality of the computers mean even the RWD version will have better traction than you might expect.

High torque FWD vehicles aren't exactly that great in the snow either. I think you would want RWD in an electric.

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