To D or not to D

[Nickdp]

Did not want to hijack another thread where I asked the question to go dual or not...

Dual motor is a bit noisier than single motor, because the driver is so close to the front motor and can easily hear the whirring sound. Nowhere near as annoying as an ICE, of course, but sometimes I still wish it could be quieter.

I have an 85 and am sometimes alarmed by the way the back skips on rough road under full acceleration. Also dual provides better range on the highway.
But no problems - I always want that little more...

Mine is a 70 (not D) and I'm loving it....I too prefer just rear wheel drive and since I'm not interested in 0-100 speeds and will not do long trips all that often I just went a 70 with a bunch of the options I thought I'd like the most. Get a 70 if you don't need the extra range.

Do you drive anywhere that requires the traction control of all wheel drive? If you do, dual motor is for you. Do you want to track your car? Ditto. If you don't fit those two categories, why waste your money? The rear wheel drive car ( non P), is incredibly powerful, accelerates freely and with surprising lightness including going uphill, so why do you need the additional hp? Perhaps I can't corner as fast as with all wheel drive, I don't know, but either way, my wife would not tolerate it, she doesn't like the acceleration I already have!!
If single motor is phased out by the end of this year as rumored, then obviously I would take dual motor. Certainly, I would not seek it out though!

<snip> here are some more reasons why dual motors are beneficial:

1.Torque sleep - allows for improved efficiencies & longer range. Apparently torque sleep is now implemented on RWD cars in 7.0, although not sure how that works in concert with regen, maybe only when idling in traffic? Also note that the model with the longest range is the 90D…by a fair margin over the RWD 90…532 km vs 560 km. That’s a 5.2% increase, almost as much as increasing the battery from 85 to 90 kWh.

2. Redundancy - ok not a huge consideration due to the reliability of the drivetrain but it has been mentioned (by Elon from memory), should one of the motors shut down for any reason, the other will take over, negating the need for a flatbed ride to the service centre.

3. Motor sound in the cabin - ok already mentioned but that’s a positive for me and can’t figure why it could even be considered a negative

4. Tire wear - more even wear distribution?

5. There must be more…maybe not.

I have an 85 and an 85D. Both near identical other than the D. I drive them both almost equally.
The D is noticably better handling, even in the city. Indeed it makes it feel like a smaller sportier car. There is an additional motor note up front, which I like. Havnt used the frunk in either yet. Having said that, the non D is also manificent and you couldn't be disappointed, its just that the D is magnificent plus a bit more. Around the city, the 70 is ample range. Never use the range of the 85's. Never use the full acceleration of either....so for me the P would be a waste. With a choice of keys on the hanger, I always go with the D.

When I ordered my 70 my head said I don't need dual but my heart said 4 driving wheels is better .. given the difference between RWD and dual is about $9000 incl. LCTax this is a topic that would assist me (and prospective new owners) to think through all the issues whether to go 'D'.

 

[omniwolf]

I've ordered the 70D (delivery in Feb supposedly!).
The reasons why i decided to get D:
- Range/cost compromise.
- acceleration
- safety

- and the big reason: I'm a nerd at heart. I loved the fact that on a normal car it's a given that a 4WD version of the same car is _always_ slower and less efficient, but on the Tesla, because everything comes down to split second timings, they are actually able to make the car faster and MORE efficient with two motors, even with the extra weight. This fact blew my mind, and i love telling anyone who will listen to me about it.


Currently i'm attempting to plan a trip from Sydney to Adelaide, and the 70 is giving me range anxiety (mainly between Euora and Adelaide). I'll post something about this trip soon and get everyone's opinions, but if i had my time again i would seriously consider the 85 (non-D), just for the range. I wonder if it's too late to change it now...

 

[ICUDoc]

I'm a nerd at heart. I loved the fact that on a normal car it's a given that a 4WD version of the same car is _always_ slower and less efficient, but on the Tesla, because everything comes down to split second timings, they are actually able to make the car faster and MORE efficient with two motors, even with the extra weight.

THIS!!
.....I am among friends, here......

 

[Keiron]

Gudday Ominwolf

I carry a 10 amp single phase portable charger module for motel stays- although you must specify be able to park outside your unit!.
Also I now have a 415 22kw 3 phase module both from Tim. The one thing I find the country runs is local mechanics are more than happy to let you bolt up for 3 phase quick charge as along as you take them for a test spin then answer 2000+ questions. :biggrin:

 

[ColinA]

When I ordered my 70 my head said I don't need dual but my heart said 4 driving wheels is better .. given the difference between RWD and dual is about $9000 incl. LCTax this is a topic that would assist me (and prospective new owners) to think through all the issues whether to go 'D'.

After my test drive, I initially thought a 70 would be quite enough. By a week later when I ordered I had come to the conclusion that the AWD was the way of the future for Tesla, better resale, better performance, better handling, better economy, better... pretty much everything, so I put my order in for a 70D.

During the week I had to make changes to my order before it was "confirmed" I started factoring in the typical 90% charge, and "real world" usage and decided I might regret not getting the 85, particularly for the country drives my wife and I like to do. If all you do is daily city drives then it's no big deal. I'll admit the "nice to have" of even more performance sounded nice too, and in that week I changed my order to an 85D. Personally I couldn't justify the substantial cost leap to a "P" as the 85D is already quick enough to give a real thrill, and impress anyone you take for a test drive (which I gather is mostly about the only time you use all the performance).

 

[Dborn]

After my test drive, I initially thought a 70 would be quite enough. By a week later when I ordered I had come to the conclusion that the AWD was the way of the future for Tesla, better resale, better performance, better handling, better economy, better... pretty much everything, so I put my order in for a 70D.

During the week I had to make changes to my order before it was "confirmed" I started factoring in the typical 90% charge, and "real world" usage and decided I might regret not getting the 85, particularly for the country drives my wife and I like to do. If all you do is daily city drives then it's no big deal. I'll admit the "nice to have" of even more performance sounded nice too, and in that week I changed my order to an 85D. Personally I couldn't justify the substantial cost leap to a "P" as the 85D is already quick enough to give a real thrill, and impress anyone you take for a test drive (which I gather is mostly about the only time you use all the performance).

Except when you want to get yourself out of a tight spot!

 

[omniwolf]

Gudday Ominwolf

I carry a 10 amp single phase portable charger module for motel stays- although you must specify be able to park outside your unit!.
Also I now have a 415 22kw 3 phase module both from Tim. The one thing I find the country runs is local mechanics are more than happy to let you bolt up for 3 phase quick charge as along as you take them for a test spin then answer 2000+ questions. :biggrin:

yeah, i plan on this. I don't want to hijack this thread, so i'll start another soon

 

[Jude]

My last ICE was the Audi Quattro and after the all-wheel drive there I couldn't imagine going back. Same with the glass roof. Both are must-haves for me now.

 

[Nickdp]

...<snip>.. I initially thought a 70 would be quite enough ... later ... come to the conclusion that the AWD was the way of the future for Tesla, better resale, better performance, better handling, better economy, better... pretty much everything, ....

well said - I think the points you raise are at the heart of this debate i.e. the characteristics that make the Model S so special are extended just that little bit further. Such a consideration has to be balanced with the extra cost.... and that is where it comes down to personal choice. So far I'm leaning towards Dual.

In the interests of a balanced discussion I would love to see some more comments against.

 

[paulp]

Except when you want to get yourself out of a tight spot!

the 85D, even the 85, are very quick at getting you out of a tight spot. Much more than any ICE car I've ever been in, other than that hideous hotlap with dick johnson around the adelaide circuit.

- - - Updated - - -



In the interests of a balanced discussion I would love to see some more comments against.[/QUOTE]
Given Colina's somewhat accurate comment about the D doing things better, I think the only comment against going D could be cost, although some complain of additional noise up front. Some complain of the smaller frunk.
I like the noise, it sounds like the future, and I never use the frunk as the boot is huge, and when I ordered the cost difference was 5k, so I don't see any realistic negatives in going D. Can anyone think of any negatives other than these 3?

 

[baillies]

I think Dborn also mentioned a while ago CV joints and related maintenance but I guess we have a while before we know how reliable the D steering system is compared to the non D. Consumer reports recently mentioned overconfidence in snow being an issue with 4WD but not directly related to D and not relevant for 99.99999% of km's travelled in AU.... I also saw a reviewer that mentioned the non D is more fun due to being able to 'play' with the rear end grip and this was not possible in the D.

More even tyre wear is I guess another advantage of D.

 

[BenT]

I have an 85. Have never missed having the D. Living in Adelaide I will likely never drive on snow/ice and on the occasional dirt rd the rear wheel drive has been fine. I have more Frunk room and as we have a big dog I use the Frunk on family trips and the dog goes in the trunk. I have more than enough acceleration. I have the air suspension, premium interior/lighting and autopilot and I would rather spend money on these options than an additional engine. Every day with general commutes and with family trips I enjoy the options and I don't think I could say the same for AWD.

 

[EcoCloudIT]

Couldn't agree more BenT....I'm not interested in straight line acceleration and will never go off-road to to the snow....I also might get accused of driving like a granny (achieving around 180 at the moment)....I don't feel I do but the numbers kinda suggest I do....I'm not sure what the average age of Tesla owners are in AUD but at 44 I guess I fit in the middle? Maybe I got used to driving slow due to the continually nagging of my better half ;-)

Dual does nothing for me, although I can see why others deem it as mandatory.

(This is coming from someone that had the options of D or non-D when ordering.....so no sour grapes ;-)

-ECIT

 

[paulp]

I have an 85. Have never missed having the D. Living in Adelaide I will likely never drive on snow/ice and on the occasional dirt rd the rear wheel drive has been fine. I have more Frunk room and as we have a big dog I use the Frunk on family trips and the dog goes in the trunk. I have more than enough acceleration. I have the air suspension, premium interior/lighting and autopilot and I would rather spend money on these options than an additional engine. Every day with general commutes and with family trips I enjoy the options and I don't think I could say the same for AWD.

My last car, a small low audi tt, had awd. It certainly wasn't intended for off-roading (4x4). All wheel drive gives noticable handling improvements in normal daily driving, and isn't always about achieving more acceleration. Indeed I agree that the 85 has plenty in that regard, but the D car is just sublime to drive, and I dont use any more acceleration as a consequence.

- - - Updated - - -



(This is coming from someone that had the options of D or non-D when ordering.....so no sour grapes ;-)

-ECIT[/QUOTE]
same bere ECIT, although I ordered one of each as I was unsure which was better. Still a tough decision around which is better, although I think the D is better by a small margin. The wife doesn't agree. She can't tell the difference. For her acceleration has no relevance, nor does spirited cornering.

 

[dogphlap]

Mine is a 70D.
Cons for choosing a D: much reduced frunk space, higher cabin noise (not that it's loud, barely audible really) the inability to throttle steer the car through corners and higher purchase price.
Pros for choosing a D: Accelerating on wet roads is surreal, it's as if the road was bone dry, it just feels so much safer. Less stress on the drive units and tyres since acceleration and regenerative braking loads are shared between front and rear. If your driving ever involves ice or snow get the D, even on wet roads it is much better than my rear wheel drive ICE car.

Whichever you choose you will still love the car.

 

[googie]

After reading through a number of comments suggesting AWD improves handling (and somehow makes a car feel "smaller, sportier"), I thought I would point out that as a general rule, AWD does not improve the cornering ability of a car compared to RWD.

The extra weight of AWD (in the case of the Tesla D, a whopping 132kgs sitting right on the front axle) means that braking, initial turn in speed, mid corning speed and the turning circle is usually always worse than a comparable RWD car.

There is a myth among some people that AWD somehow makes you corner and/or stop faster. This is not true. Also the comment suggesting to get a D if you want to track the car is questionable. Most track/race cars are RWD.

I've owned two off road vehicles with "part time 4WD" which you either run as either RWD or manually select 4WD. I can absolutely assure you their corning ability was not magically improved when it was selected to 4WD. However steering was heavier and torque steer became prevalent.

AWD can get you better launch speeds and initial acceleration out of hard corners in certain situations. But in my test drive of a Tesla P85, which was on dry tarmac and involved several full throttle launches off the lights and out of tight corners, there were no situations where AWD would've given better launch speeds or corner exit speeds.

AWD gives the motor more potential to get extra power down to the road. But if you can use full throttle and do not get excessive wheel spin in a RWD as was my experience in a RWD Model S, AWD will do nothing.

Obviously the D models get better acceleration (though in car talk, acceleration is not considered part of handling) but this comes from the extra motor not from having AWD. If it had the traditional AWD - eg the same single rear motor with power being fed to the front wheels, the AWD Tesla's would be slower than RWD.

 

[raynewman]

After reading through a number of comments suggesting AWD improves handling (and somehow makes a car feel "smaller, sportier"), I thought I would point out that as a general rule, AWD does not improve the cornering ability of a car compared to RWD.

The extra weight of AWD (in the case of the Tesla D, a whopping 132kgs sitting right on the front axle) means that braking, initial turn in speed, mid corning speed and the turning circle is usually always worse than a comparable RWD car.

There is a myth among some people that AWD somehow makes you corner and/or stop faster. This is not true. Also the comment suggesting to get a D if you want to track the car is questionable. Most track/race cars are RWD.

I've owned two off road vehicles with "part time 4WD" which you either run as either RWD or manually select 4WD. I can absolutely assure you their corning ability was not magically improved when it was selected to 4WD. However steering was heavier and torque steer became prevalent.

AWD can get you better launch speeds and initial acceleration out of hard corners in certain situations. But in my test drive of a Tesla P85, which was on dry tarmac and involved several full throttle launches off the lights and out of tight corners, there were no situations where AWD would've given better launch speeds or corner exit speeds.

AWD gives the motor more potential to get extra power down to the road. But if you can use full throttle and do not get excessive wheel spin in a RWD as was my experience in a RWD Model S, AWD will do nothing.

Obviously the D models get better acceleration (though in car talk, acceleration is not considered part of handling) but this comes from the extra motor not from having AWD. If it had the traditional AWD - eg the same single rear motor with power being fed to the front wheels, the AWD Tesla's would be slower than RWD.

What you say is probably correct for an ICE 4WD but is not valid for a Tesla. There is no comparison (other than the number of wheels) between the systems.

 

[googie]

What you say is probably correct for an ICE 4WD but is not valid for a Tesla. There is no comparison (other than the number of wheels) between the systems.

Then explain to me how a Tesla D can brake quicker and enter corners quicker when it has a extra 132kgs sitting right on the steering axle?

 

[raynewman]

Then explain to me how a Tesla D can brake quicker and enter corners quicker when it has a extra 132kgs sitting right on the steering axle?

Firstly, the weight (mostly) does not sit on the steering axle; it sits under it largely eliminating body roll. Having said that, It brakes better due to better brakes. The main feature of the 'D' is the 'stick to the road' ability.
The RWD Model S 85 will let go in the wet or on a rough road or severe cornering under hard acceleration whereas the 'D' just doesn't.
The Tesla 4WD system does not use brakes to balance power as ICE systems do and hence is inherently more stable.

 

[googie]

Firstly, the weight (mostly) does not sit on the steering axle; it sits under it largely eliminating body roll. Having said that, It brakes better due to better brakes. The main feature of the 'D' is the 'stick to the road' ability.
The RWD Model S 85 will let go in the wet or on a rough road or severe cornering under hard acceleration whereas the 'D' just doesn't.
The Tesla 4WD system does not use brakes to balance power as ICE systems do and hence is inherently more stable.

Looks above the axle to me. Not sure how it could possibly fit underneath.

Can you reference the better brakes? Tesla's specifications show the same brake set up for both. Regardless, upgraded brakes do not mean better stopping distances (assuming no fade). Better braking comes from increased traction from the wheels/suspension. Extra weight no matter where it's placed, decreases braking ability. It is simple physics.

As I already said AWD can improve exit speeds under slippery conditions out of hard launches or tight corners. But they cannot improve braking distances. They cannot improve corner turn in or mid corner speeds. The extra weight will reduced cornering speeds.

ICE 4WD systems do not use brakes to balance power. I'm not sure if you've ever looked under a 4WD and seen how the driving rear wheels are connected to the front driving wheels but it is not through brakes. It is through differentials/axles. The 4WDs I owned had the drive balanced in a fixed 50% split front to rear axle. Most 4WDs have a fixed balance which is done mechanically. The differentials in some 4WDs can mechanically change the balance power during slippage. A very small number have mechanical and electronic setups that can vector power to individual wheels as desired (and the Model S does not do this).
Perhaps you were thinking of traction/stability control systems which can apply braking to individual wheels. That has nothing to do with 4WD. You will find that on any car with traction control whether FWD, RWD or 4WD.

In any case, no matter what AWD system is fitted, you are not using it under braking or turning into a corner! You are using the tyres, steering brakes and suspension - and when carrying a AWD system as opposed to RWD, they are having to support more weight which make it harder to stop or turn.