Dual motor vs. RWD in winter driving.

[Raindog1]

I haven't been able to find a good thread on this subject even though I'm sure it exists.

Does the extra costs warrant the getting a car with dual motors??? My main concern for getting Dual Motors would be winter handling but I'm unsure of the extra cost?

What is your experience/thoughts?

 

[bkp_duke]

RWD on snow or ice? Just stay home unless you want your car in a ditch, or worse . . .

 

[AWDtsla]

I got my car stuck in a few inches of dry fluffy snow 2 days ago. It was frankly embarrassing. It seemed to be effectively 2WD, with diagonal wheels spinning with apparently no differential braking. On top of that, even with slip start on, the computer kept cutting throttle when a little more spin would have likely gotten me moving, then at the same time the car was lowering the suspension automatically from very high. I mean, WTF. I've been through packed/plowed snow 3 times as high in my old subaru, which had limited slip center/rear but open front.

So.. RWD good enough? I can't for the life of me imagine how...

</rant>

 

[wdolson]

From what people with original RWD Model Ss who live in snow country have said the RWD Model S performs better on snow and ice than any ICE AWD car (one guy here on the forum from Ontario, Canada said it did better than his Subaru ever did). The low center of gravity, regenerative braking, high weight, and having the weight distributed in the center of the car all contribute to stability on snow and ice.

The dual drive Teslas are even better. We had some nasty ice here about a month ago and my S 90D was staying stuck to the road when the 4WD trucks were sliding around. It was no more dicey than driving on a dirt road.

The dual drive Teslas do have other advantages, they have 4 wheel regen braking which helps to put more energy back into the battery and helps brake on ice. With the braking happening at the axle instead of the wheel, regen braking is much better on ice than regular car brakes. Another advantage of the dual drive is better range under all conditions. It's unusual that something that adds some capability also improves in other areas without any serious drawbacks.

IMO, the only reason not to buy a dual motor car would be the cost savings. There are no other drawbacks to it.

 

[M5Guy]

AWD is going to be better than RWD for acceleration. Deceleration (arguably the most important part) will be nearly the same. By far the largest influencing factor is tire selection. Summer performance tires and winter don't mix. All season tires are a compromise on all fronts.

I put my RWD P85+ away for the winter until the snow clears here in Michigan.

 

[Saghost]

I got my car stuck in a few inches of dry fluffy snow 2 days ago. It was frankly embarrassing. It seemed to be effectively 2WD, with diagonal wheels spinning with apparently no differential braking. On top of that, even with slip start on, the computer kept cutting throttle when a little more spin would have likely gotten me moving, then at the same time the car was lowering the suspension automatically from very high. I mean, WTF. I've been through packed/plowed snow 3 times as high in my old subaru, which had limited slip center/rear but open front.

So.. RWD good enough? I can't for the life of me imagine how...

</rant>

That's odd. We have videos of Xs starting and stopping in ditches with one wheel completely in the air, and the car using the brakes to control wheelspin on it.

 

[Dax279]

I think you need to look at the conditions you will be driving in and decide just how often you feel you might need AWD.

My previous car was a v8 RWD and I owned that car for about 7 years. I always used Nokian winter tires on the car. In all those seven years of winter driving I only once chose to stay home and not go out one night for a dinner when the snow was bad because I was worried I might not get up a hill that I knew would be bad. I will say though that I drive the car through some pretty bad storms through the mountains a few times and it was pretty solid. Based on what I read hear, the RWD MS performs very well because of where the weight of the car is.

If I lived somewhere hilly then I would definitely would have second thoughts owning a RWD car.

One thing to keep in mind with AWD is that most people in snowy climates seem to feel it is a must have even though it is not and so resale value and ease of getting a sale you might consider spending the extra now.

With my current car, I chose the dual motor and have been very very happy. This has been a snowy year and the car has handled excellent. My choice was between a RWD MS with winter package or the AWD without and to be honest this has been a very very cold winter and I have not once wished I had the cold weather package.

 

[AWDtsla]

That's odd. We have videos of Xs starting and stopping in ditches with one wheel completely in the air, and the car using the brakes to control wheelspin on it.

Yeah, I assume a lot of it is luck and confirmation bias. "I got through the snow one time" is not an accurate description of performance.

I even had one wheel on bare concrete. Even with an open front diff, my subaru would have pulled out of it...

 

[robby]

With the braking happening at the axle instead of the wheel, regen braking is much better on ice than regular car brakes.

Can you elaborate on this? My understanding is that braking on ice is inherently a traction problem -- not clear how axle vs wheel is helpful.

 

[Gig103]

AWD is definitely easier than RWD, but remember it only gets you going it doesn't necessarily stop you. In Germany, I understand that people buy RWD but snow tires and it's probably the best option. But storing a second set of tires and wheels is tough, so AWD with M+S tires and careful driving is okay.

Even with Dual motors, I do not want to drive on snow with my 21" tires.

 

[thefortunes]

AWD is definitely easier than RWD, but remember it only gets you going it doesn't necessarily stop you. In Germany, I understand that people buy RWD but snow tires and it's probably the best option. But storing a second set of tires and wheels is tough, so AWD with M+S tires and careful driving is okay.

Even with Dual motors, I do not want to drive on snow with my 21" tires.

I'm not sure why you think having a second set of wheels/tires is tough - yes, it costs you additional $ (mainly for the wheels, as you are wearing the summer tires out less if you are running winter tires so there is no cost differential there) but they store in a very small (19" diameter x 4') area.

I have run winter tires on our 2 primary vehicles for the last 20 years, many of which have been RWD. Our RWD Model S and RWD Roadster are our current daily drivers in the winter here in Wisconsin, and we have never had an issue.

Additionally, RWD with winter tires gives you MUCH better control than AWD with all-season tires.

<"

>

To answer the OP, AWD with winter tires is best, but IMHO not necessary as Tesla's traction control is excellent.

 

[Gig103]

I'm not sure why you think having a second set of wheels/tires is tough

It's a matter of storage. 2 cars in snowy climates, that's 8 tires. People in condos or apartments aren't necessarily going to have that kind of space.

 

[dgpcolorado]

I went through this discussion in earlier threads on winter driving. My experience:

I tried very hard to keep my RWD going this winter without snow tires by using chains to get up my long steep driveway. It works but is a pain. We have had a crazy winter here: warm, very cloudy (unusual in sunny Colorado) with lots of snow and rain (rain? in January?). The rain turned parts of my driveway to glare ice for a time, something I haven't seen before in my 32 years in Colorado. Since roads here are plowed and sanded promptly, the vast majority of my driving is on clear, usually dry, roads. But my driveway and dirt road cul-de-sac are often snowpacked for long periods of time in winter.

At the end of January I finally gave up and bought snow tires (Michelin X-Ice 3), thus ensuring the end of the snow for this winter (and, likely, next winter as well). Despite the return of sunny weather, my driveway stayed icy for many days and the dirt cul-de-sac stayed snowpacked for longer, until it melted into deep slush. So, I found that the snow tires stuck very well to both ice and snow and helped with pushing through deep slush. Despite driving mostly clear dry roads (in the 50s and 60s F) most of the time, the snow tires sure helped with my driveway and cul-de-sac. As expected.

If you live in the flatlands an AWD car with regular tires might be ok on snowpacked roads. If you deal with steep hills you need either snow tires or chains, regardless of whether or not you have RWD or AWD.

As others have said many times before me in other threads, a Tesla RWD with (good) snow tires makes for a very capable snow car. The modern traction control helps a lot. Even on hills and curves. Would AWD be even better? Yes, of course. An advantage of AWD is that you can might get by with regular tires in moderate winter conditions on the flatlands. If you deal with serious winter conditions or steep hills and sharp curves, you would need snow tires (or chains) regardless of whether on not you have RWD or AWD.

All of this assumes careful driving in winter conditions. In Colorado, SUVs are notorious for being seen upside down along freeways because the drivers were going too fast for the conditions. Just because AWD can help get you going doesn't mean you can stop in icy conditions. (For my purposes getting going is the important part because my county is excellent in plowing and sanding the very steep roads.)

Would I buy dual drive for an extra $5000? Yes, for a number of reasons (handling, range, front regen braking). But RWD + snow tires is good enough IME.

FWIW.

^ Mountain Tesla, with snow tires, two weeks after being washed.

 

[JOEV1]

Friend of mine had a P85+ for about a year. He lives at the top of a winding road. (about 15 km up the mountain) I ask him how was Your winter driving?
He said no problem at all. (on winter tires of course)
Now he is saying, since I got my Dual Motor, he feels much safer and relaxed going up or down.
But, he mentions, when I was driving the P85+ I had to get NEW Rear TIRES after only 6000 km!
(sure, he said, it was a lot of fun with RWD)

 

[JRMW]

There is no comparison between an Tesla with winter tires and AWD vs a Tesla with winter tires and RWD. The AWD is far superior.

I think a RWD Tesla on all seasons in Ontario should be illegal.

My partner at work had RWD Tesla on all seasons. We had a 6 inch storm or so. Nothing special. He was stuck in a flat parking lot. We had to push him out. He barely made it home.

He switched to winter tires. Capable is a good word. Works about as well as an AWD ICE on all seasons in terms of getting going. It obviously stops and corners better than any car on all seasons. (Remember, AWD does NOT help you stop or stay in the road... it gets you going). It still has issues getting through snow banks after they plow so he doesn't drive it in snow days and 1-2 days after.

My AWD is 100x better in winter. I feel very safe, and its only problem is the low clearance. But it's a great car. I drive it in snowstorms

As good in snow as a Subaru on winters? No. But the best sports car I've ever driven in snow

I see zero reason to get a RWD Tesla in Ontario. None.
More importantly- get winter tires

If you're dropping $70k+ on a car, don't skip out on the important things that will save your life

 

[mspohr]

AWD gives much better handling, acceleration and braking in all road conditions... dry, wet, snow, ice.
I live in the mountains and I always buy AWD cars so I bought an 85D. Absolutely solid handling in all conditions.

 

[thefortunes]

For the OP, to summarize the various opinions here for capability in the snow (remember capability is more than acceleration, you also need to be able to turn and stop):

Best - AWD with winter tires
Next - RWD with winter tires
Next - AWD with all-season tires
Next - RWD with all-season tires
Next - AWD with summer tires (really shouldn't drive on summer tires below 40F or on ANY snow/ice)
Worst - RWD with summer tires (really shouldn't drive on summer tires below 40F or on ANY snow/ice)

 

[Yinn]

I own a S60D. I've had a S85 RWD as a loaner and drove both in the snow.

They were both fine. Traction was not an issue in the rwd. Stability wasn't really a concern as long as I didn't mash it at every opportunity. Stability wasn't an issue in either of them. They both performed admirably.

Is it worth the extra cost? That's up to you. My wife drives he S60D mainly, for me it was worth the extra cost. If I were to buy for me, I'd just get a rwd one and I'm not sure the rwd would be.

I like comparing apples to apples. So I'll avoid the whole winter tires argument. Like for like, you can't deny the AWD will perform better. The question is if you'll need it. Also note, you give up some steering feel with the AWD over the RWD.

 

[wdolson]

Can you elaborate on this? My understanding is that braking on ice is inherently a traction problem -- not clear how axle vs wheel is helpful.

I did a search for an explanation, but didn't find what I was looking for. I remember something about this when I took Dynamics in college. My major was Electronic Engineering and we had to take some Mechanical Engineering courses as support courses (Statics, Dynamics, Thermodynamics, and Materials Science 101). I haven't used it since graduating in 1988, so my memory is not crystal clear.

Where a force is applied in a system can make a major difference in performance, that I do remember.

I did find keeping control in the snow was much easier in the Model S than any car I've ever driven in snow including a couple of Subarus including my SO's 2013 with traction control. Maybe it was other factors, but slowing with regen on the ice felt very solid.

 

[sorka]

I got my car stuck in a few inches of dry fluffy snow 2 days ago. It was frankly embarrassing. It seemed to be effectively 2WD, with diagonal wheels spinning with apparently no differential braking. On top of that, even with slip start on, the computer kept cutting throttle when a little more spin would have likely gotten me moving, then at the same time the car was lowering the suspension automatically from very high. I mean, WTF. I've been through packed/plowed snow 3 times as high in my old subaru, which had limited slip center/rear but open front.

So.. RWD good enough? I can't for the life of me imagine how...

</rant>

A few weeks ago, I got to test my brand new AS3+ tires on my P85D on a steep ice covered driveway. The driveway can't be walked on without slipping...that's how bad it is. I tried the previous week in my prius with tire chains and it was a no go. The Tesla went up without any slippage like it was just the dirt that's under the ice rather than the ice itself.

By far the most capable of the AWD and 4x4 vehicles I've owned. I think tires might make a big difference. The AS3+'s have an excellent ice and snow rating from user surveys on the tire rack. Interestingly, the non plus AS3s have a lousy rating.