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Comment by pasta | Hacker News Reader

You must be a drunk engineer.

It's about pulling or pushing the car.

When it snows all BMWs get stuck here.

The difference is that a traditional RWD car has a heavy engine in the front, but is being pushed from the back where none of the weight is. So lack of traction and fish tailing is the obvious result.

However, I think a RWD electric car would have less problems with traction (and thus, fish tailing), since the weight is distributed over the length of the car more evenly.

I think push vs pull is legit, but I don't think it would be as much of a problem when all the weight isn't in the front. I'd be interested to hear from some Tesla owners who drive RWD in the snow.

Not really...check weight distributions for any modern vehicle, you will find the majority of the competent manufacturers get it right around 50/50 front/back. Meaning your FWD Honda has no advantage over a RWD BMW except for the tendency for the Honda to understeer and the BMW to oversteer. This is the main problem in less than ideal traction conditions...

Define "competent manufacturer".

I'd be willing to wager that most front wheel drive sedans sold in the US are closer to 60/40, not 50/50. Pickup trucks (very popular in the US) also have a weight distribution much more skewed to the front.

50/50 distribution is more common for sports cars sure but that is not the majority of cars sold.

This is true, at least for premium cars. However even if the FWD honda and RWD BMW are similar in the flats. The hardest thing to deal with when it's slippery is the climbs, and then the RWD has the advantage.

Even on the flats, when cornering the FWD has the front wheels steering and accelerating, while the RWD uses different wheels for that. Granted not a big difference, especially since when it's slippery you aren't using many HP.

When the force vector is coming from the back it has the tendency to go into any direction. When there is enough grip in the front you can steer. A heavy engine in the front means even more grip.

But that's all useless on ice. Even if the car was 100% balanced.

FWIW, a traditional RWD car is usually pretty close to 50/50 weight distribution, while a FWD car is usually closer to 70/30.

However a RWD racing car is typically also biased with more weight on the driven axle, e.g. the Porsche 911 is around 40/60. So it's pretty pretty clear that more weight on driven axel == good. It's just not possible to get 40/60 in a BMW 5-series type car while keeping the practicality.

Anecdote: growing up in the UK in the 70s / 80s, snow was rare and most drivers didn't know how to cope. RWD was common in Cortinas, Sierras etc but it was the little rear-engined, RWD Skoda Estelle that I remember doing the best in the snow. I particularly remember an orange one weaving past abandoned cars.

With "normal" cars, there are two differences between front and rear wheel drive: one is the tendency to under vs oversteer, which does not affect your ability to get going. The other is the fact that front-wheel drive cars have the weight of that heavy IC engine over the driven wheels, giving more traction. Grandparent was pointing out that's not the case with a Tesla.

When I grew up in Sweden everyone had RWD cars and got around fine. But it was common to put some sand bags or lead shot in the trunk to get more weight on the rear wheels. The other thing you need are real snow tires.

In my country where there is usually snow on the roads, or at least ice, for most of winter, BMW saloons (RWD) are pretty common here too. I think people buy them on purpose so they can slide around tight corners.

RWD is no issue in the snow, if there is enough weight on the rear wheels, as in cars like the 911 and the VW beetle. RWD is only an issue, if the engine is in the front of the car. Most electric cars have the battery in the middle of the car, putting enough weight on the rear wheels. Additionally, traction of electric cars can be controlled much better than with combustion engines.

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