Is an AWD Model S Necessary?

[ahimberg]

Many of the cars the S is compared to (audi a4/a6/etc, BMW 5/7 series) have AWD as an option -- not having it could hurt some conversion sales?

As for snow/ice driving, I think there is some difference depending on how steep the hills are you're driving on. I've got a Prius and a Subaru, the Prius's traction control kicks in and won't let you accelerate again for a second to two, long enough to slide backwards making it impossible to go up steeper hills. (Not sure how big the hills are in Dallas, but there are some pretty steep and twisty ones I have to drive on every day, and for me its more about driving on ice than snow... in the seattle area we don't get much snow pack, just melted and refrozen snow). I hope the S's traction control is a lot better (as is claimed) and I won't need to shop for an AWD car after getting the S (S and X will break my budget).

 

[zachster]

I seem to remember the biggest advantages of the Model X 2nd motor being:

- more regen
- better traction, performance, speed
- higher torque curve on 2nd motor equalling better efficiency at higher speeds - this seems like a pretty big deal no?

 

[ElSupreme]

I don't believe additional regen from AWD would extend range. It is very very rare that I need more regen.
I believe that the AWD version will have slightly more drivetrain drag, and that it will hurt range by a small amount.

You would get much better tire wear though. Wouldn't burn through the rears as fast.

 

[Denis Vinnie]

An AWD Model S would meet all of my crieria for the Perfect vehicle, especially if the adjustable heigth suspension range was increased. Our Audi Allroad has more clearance then a BMW X5 when on the highest setting, there isn't anywhere the vehicle can't go, no matter what the road conditions. The additional power to the front wheels would no doubt make it a "kick ass" performance vehicle rivalling any of the exotic sport cars, 0-60 under 4 sec. ..!? The fact that this could be achieved at an operating cost 1/10th that of the gas guzzling "super cars" and still accomodate 5 passengers or, with the 35% split rear seat down, 4 passengers and all their ski gear (in a ski bags, which is what we do now in the Audi, I personally don't like appendages hanging from my car ) ...Wow! Not having a hump intruding on the leg room for the middle passenger in the back seat makes far more accomadating, the rear trunk well (where ICE vehicles have the gas tank ) is a huge, deep storage space, pair that with the possible left over frunk space, the Tesla Model SX would make it the best of All Worlds!

 

[Robert.Boston]

It will be a no-brainer for Tesla to offer an AWD Model S once the AWD Model X is in production. Given the skateboard technology platform, I'm assuming that only minor changes to the frunk and software would be needed at that point.

 

[JohnEC]

You would get much better tire wear though. Wouldn't burn through the rears as fast.

I think that might be a pretty good advantage. Besides, if you could set the rear wheels to drive and the front ones to regen, maybe you could drive forever w/o recharging! :smile:

 

[BryanW]

I live in Utah, on a steep hill, not far from Sundance. For work, I frequently need to go between home and work in the middle of the night. During the winter, I am frequently driving snow covered and icy roads at night before the snow plows are able to clear the roads. On the hill to my home, I have seen my neighbors cars, FWD and 4WD, parked at the bottom of the hill as they could not make it from the entrance of the neighborhood to their home. I had a Corolla (FWD) which could at times not climb the hill. I now drive a Subaru Outback, and have never had an issue. I once encountered a neighbor in his 4WD truck spinning out at the bottom of the hill (about 8" of snow on the road) at 2am. I was able, without problem, to climb the hill in my Subaru and he was then able to follow in my tracks.

I believe the handling and traction control of the RWD Model S in the snow will be great. I'm very interested to see how it compares to my Subaru. My big remaining question is, how will the RWD Model S climb the hill to my home on an icy road with 8" of snow at 2am? I would love to run richkae's experiment in this very scenario. If the AWD Model S with all-seasons or snow tires performs better than the RWD Model S with either set, then I would definitely be interested in an AWD Model S.

 

[jerry33]

As for snow/ice driving, I think there is some difference depending on how steep the hills are you're driving on. I've got a Prius and a Subaru, the Prius's traction control kicks in and won't let you accelerate again for a second to two, long enough to slide backwards making it impossible to go up steeper hills. (Not sure how big the hills are in Dallas, but there are some pretty steep and twisty ones I have to drive on every day, and for me its more about driving on ice than snow... in the seattle area we don't get much snow pack, just melted and refrozen snow).

The only problem I've found in 135K miles with the Prius' traction control was the OE tires. Once a set of decent tires, such as Nokian WR-g2, or some real studless winter tires such as Nokian, Michelin, or Yokohamas are installed, traction control stops being a problem. We get a lot of 1/4" ice covering, and some hills are reasonably steep, though they aren't long as they they are in Seattle. Having lived in Vancouver for many years, I have a pretty good handle on what the snow conditions are like there--even though I didn't have a Prius at that time. It's a lot slipperier here in Dallas because the ice tends to be glare ice with a nice coating of water. It's hard to stand up on it if there is even the slightest inclination.

 

[Lyon]

I think that an AWD Model S is a great idea that we probably won't see until after Model X is out. As far as the traction goes, I find that 4WD works better in the snow even with everything else being equal. I have a vehicle that allows me to turn 4wd on or have RWD and even with studded Nokian tires I notice that it tracks better in the corners with 4wd engaged.

That said, I think that the RWD Model S is going to be brilliant in the snow when it's equipped with proper tires and rubbish with summer performance tires... because everything is rubbish in the snow with summer performance tires!

Also, can you imagine the off-the-line thrust with the extra traction of twice as many driven wheels? It's going to require a neck brace!

 

[Discoducky]

IMHO, putting a 2nd motor on the front would produce the fastest sedan on the planet due to low CG, CD, frame stiffness and power to weight ratio.

I imagine that the gear box would be different ratios for each motor so as to produce higher top end speeds without the need for a transmission.

At each millisecond I imagine that the traction computer could "launch" at the very limit of the rubber on the ground. Through every turn and straightaway for acceleration or deceleration.

In theory you could design a car where the car is only limited/bottlenecked by the grip of the tires.

 

[vfx]

Doug and GPS called it. Just plain cool.

Regen from four wheels may not give you more miles. The battery can only take so much. The S has more regen than the Roadster but it's so big it feels like less (i'm told) and that the energy input is maxed.

 

[richkae]

IMHO, putting a 2nd motor on the front would produce the fastest sedan on the planet due to low CG, CD, frame stiffness and power to weight ratio.

I imagine that the gear box would be different ratios for each motor so as to produce higher top end speeds without the need for a transmission.

At each millisecond I imagine that the traction computer could "launch" at the very limit of the rubber on the ground. Through every turn and straightaway for acceleration or deceleration.

In theory you could design a car where the car is only limited/bottlenecked by the grip of the tires.

This assumes that there is power to spare from the battery.
Since the 85kW Model S is quicker than the 60kW which is quicker than the 40kW, we know that the cars are limited by the power from the battery.

 

[pme]

Hi all,

I live in Switzerland, which for Tesla Motors is a high potential market. Small country, short distances, lot's of people with relatively high budget for cars, easy to find early adopters and on top of it: No problem at all already now to draw electricity for charging from 100% regenerative sources (mainly hydroelectric). When I look around, there is tremendous demand for AWD station wagons. Audi, BMW, Mercedes, and with SUVs the Land Rovers and Range Rovers are incredibly popular. There can be quite a bit of snow here in winter and a Model S AWD would certainly fly off the shelves, especially if it came in a "Jaguar XF Sportbrake" style.

Patrick

 

[ChadS]

Since the 85kW Model S is quicker than the 60kW which is quicker than the 40kW, we know that the cars are limited by the power from the battery.

Yet the 85kWh Perf is much quicker than the 85kWh base, which to me indicates that battery is not necessarily the limiting factor.

Maybe it is the limiting factor in smaller packs due to a different chemistry. Or maybe the batteries are all capable of much more, and Tesla is just trying to add value to the larger packs so people upgrade. I don't think we have enough info about the battery capabilities to be sure. Even if we had very specific details, I'm sure there is no line where power above hurts the battery and power below is fine. I'm sure it's a gradual effect, especially considering the high power draws are generally transient. So the limits, wherever they are, are always a trade-off between performance and life.

More on-topic, if you want off-road or cutting-edge track performance, AWD is awesome. But for regular road driving, I think Tesla's awesome traction control (combined with the right tires for the conditions) is perfectly adequate. That said, there are sure a lot of people that THINK they need AWD. Rather than add AWD, maybe Tesla should do some advertising for their traction control, showing the Model S driving on canyon walls, coming to a stop on a wet road quickly*, and passing SUVs in snowy ditches, etc.

*Yes, I know AWD doesn't help with that; but automakers make ads like that anyway. If safety is the big concern, shouldn't the drivers be going slower so it's not a life-or-death emergency if something unexpectedly appears on the road?

 

[WarpedOne]

AWD Model S will be offered after Model X has got some buyers. It would be stupid (=throwing away easy money) not to do it when you already invested into development of your own AWD tech.

Regarding regen - Model S might already have regen at max power level acceptable by batteries but this is not the real problem - try pulling handbrake in the middle of quick turn and behold the spinning horizon.
RWD regen totally breaks vehicle balance and is thus only usable under high-stability conditions like going down a straight road. On curvy roads available regen (i.e. not-vehicle-stability-breaking) level is much lower.
It is possible to somewhat offset this by heavy front-biasing the brake ratio but this is counter productive - you want to brake by electric motor and not by front disc brakes.

In AWD vehicle regen does not pose this problem - max regen power is almost always available (except on slippery roads of course). Regen in the middle of the curve fills like stepping on classic brakes and not like pulling a handbrake any more.

I'd guess when EV era really comes and EVs are standard and ICEs exception, AWD is standard and 2WD exception/only available on chip/entry models.

 

[richkae]

One big reason IMO to offer AWD is that electric AWD will be so much better than a mechanically linked AWD.

 

[jerry33]

Regarding regen - Model S might already have regen at max power level acceptable by batteries but this is not the real problem - try pulling handbrake in the middle of quick turn and behold the spinning horizon.

Not with vehicle stability control. If Tesla's version works as well as the Prius' version, you're going to have to work very hard to get it to spin--even on glare ice.

 

[Doug_G]

I'm not convinced that AWD is a good thing for track performance, as it has some of the disadvantages of FWD. I've actually driven an AWD car on the track, and it tended to understeer when trying to accelerate out of the corners. I'm much faster in a more conventional, better balanced, and lighter weight RWD car.

 

[grisnjam]

So who wants to see if they can bring this new thread back on topic? Anyone?

Necessary or not I think they will do it in the future. With support for AWD in the X it is a no brainer. What I want is a Performance Gen III with AWD.

 

[Tessier]

This is a question Audi and Subaru have answered nicely! I live in the North East and let's just say the weather isn't the best. I love my Audi in the winter but i'd love an AWD Tesla even more. Unfortunately they don't make one and as of right now don't have plan's to offer one. I personally think the Model X is just plain ugly! Like couldn't fly out of the ugly tree with it's falcon winged door's so it landed on it's head and started chewing on the ugly tree's roots kind of ugly. and personally the whole CUV thing makes no sense to me so a performance AWD Model S ya now you'd have a deposit from me!:love: Till then i'll sit on the side lines and keep wishing!