Model 3 AWD on Slick Pavement

[niteman1946]

Hi Group, new poster here.

We have a Long Range AWD that we acquired in November of last year (2018). I do most of the driving with the M3 and had selected the AWD because my previous (ICE) cars had been AWDs. I always felt they were steadier on wet and icy surfaces.

There's been three incidences with the M3 that make me wonder if its AWD function is the same as my previous cars.

1. The M3 was but a few months old when I parked it on wet soil. Upon leaving I backed the car out and while successful, the rear tended to "slop" around. Thought that was curious.

2. Just recently on a rainy day the car's back end broke traction while making a turn, with the rear end swinging wide. This happened twice on the same day on different pavements, but each time in the rain. The first was at about 10mph at a somewhat odd down hill left turn. The second was on level pavement at about 40mph, and I gave the accelerator just a slight bump while going around a right hand turn. Both these incidences surprised me.

I had not experienced this behavior with previous AWDs.

I recently read an article about the possibility of a two-speed tranny in future BEVs. In the article there was an aside about how Tesla had effectively accomplished the same thing with the M3 AWD. That is, front drive with one ratio and rear drive with a different ratio. One drive for acceleration and the other for highway speeds.

Assuming the car is performing as intended, my experiences suggest that the M3 does not actually function as an AWD, but rather as an either/or drive.

I've seen no web comments on this characteristic, so I'd appreciate any thoughts other users might have.

Thanks,
Mark

 

[jmaddr]

Tesla’s AWD has been viewed favorably. Here is a recent stack against Audi’s Quattro:

Tesla's Dual Motor AWD tech takes on Audi's Quattro system in 4x4 roller test

Still, the fact it stepped out in you is concerning. Im not sure how powerful your other AWD were but the torque is certainly “more available” on a M3, especially at lower speed comparatively. That doesn’t mean that should have happened, only that the M3 torque could make the rear slide much easier than another vehicle with less power. Did the M3 recover quickly and the front drive pull you out of your rear end slide ?

 

[niteman1946]

All good questions.
The mud episode, while backing out of parking, struck me as there was no front wheel action . Just the rear.
The first incident on wet pavement surprised me because I was simply driving around the corner. Even so it seems all power was going to the rear. I backed off the accelerator and the car righted itself. All this was at a fast walking pace.
The second wet pavement occurred mainly because I gave the "gas" a small push, just to see if the rear would break free. And it did. I backed off the accelerator and the car righted itself.
I must say in all cases, it seemed the only drive functioning was the rear. And I fully appreciate (and enjoy) that the M3 has a lot of torque, but the slippage really bothers me.

There's been no notifications of operating problems from the car. And I've not spoken to Tesla service but may contact them about this.

Thanks for the article on Audi and Tesla. And that's the type of behavior I would expect.

Mark

 

[jjrandorin]

Hi Group, new poster here.

We have a Long Range AWD that we acquired in November of last year (2018). I do most of the driving with the M3 and had selected the AWD because my previous (ICE) cars had been AWDs. I always felt they were steadier on wet and icy surfaces.

There's been three incidences with the M3 that make me wonder if its AWD function is the same as my previous cars.

1. The M3 was but a few months old when I parked it on wet soil. Upon leaving I backed the car out and while successful, the rear tended to "slop" around. Thought that was curious.

2. Just recently on a rainy day the car's back end broke traction while making a turn, with the rear end swinging wide. This happened twice on the same day on different pavements, but each time in the rain. The first was at about 10mph at a somewhat odd down hill left turn. The second was on level pavement at about 40mph, and I gave the accelerator just a slight bump while going around a right hand turn. Both these incidences surprised me.

I had not experienced this behavior with previous AWDs.

I recently read an article about the possibility of a two-speed tranny in future BEVs. In the article there was an aside about how Tesla had effectively accomplished the same thing with the M3 AWD. That is, front drive with one ratio and rear drive with a different ratio. One drive for acceleration and the other for highway speeds.

Assuming the car is performing as intended, my experiences suggest that the M3 does not actually function as an AWD, but rather as an either/or drive.

I've seen no web comments on this characteristic, so I'd appreciate any thoughts other users might have.

Thanks,
Mark

Have you checked your tires (tread depth, wear, and brand / type for your desired conditions)?

 

[jyalpert]

Have you checked your tires (tread depth, wear, and brand / type for your desired conditions)?

I also agree this sounds like it could be tire related.

 

[KenC]

Hi Group, new poster here.

We have a Long Range AWD that we acquired in November of last year (2018). I do most of the driving with the M3 and had selected the AWD because my previous (ICE) cars had been AWDs. I always felt they were steadier on wet and icy surfaces.

There's been three incidences with the M3 that make me wonder if its AWD function is the same as my previous cars.

1. The M3 was but a few months old when I parked it on wet soil. Upon leaving I backed the car out and while successful, the rear tended to "slop" around. Thought that was curious.

2. Just recently on a rainy day the car's back end broke traction while making a turn, with the rear end swinging wide. This happened twice on the same day on different pavements, but each time in the rain. The first was at about 10mph at a somewhat odd down hill left turn. The second was on level pavement at about 40mph, and I gave the accelerator just a slight bump while going around a right hand turn. Both these incidences surprised me.

I had not experienced this behavior with previous AWDs.

I recently read an article about the possibility of a two-speed tranny in future BEVs. In the article there was an aside about how Tesla had effectively accomplished the same thing with the M3 AWD. That is, front drive with one ratio and rear drive with a different ratio. One drive for acceleration and the other for highway speeds.

Assuming the car is performing as intended, my experiences suggest that the M3 does not actually function as an AWD, but rather as an either/or drive.

I've seen no web comments on this characteristic, so I'd appreciate any thoughts other users might have.

Thanks,
Mark

If you can, try to recreate #2 in a parking lot with someone recording how your car's tail kicks out. Sounds almost like "track" mode with less traction control intervention than normal, everyday driving. Once you get it recorded, I'd take it to a SC, because that's not the normal behavior. The car shouldn't be tail happy.

 

[Trips]

Yes with all the extra instant power the back can slide out a little but will quickly correct itself. The first couple times it was a little concerning but I got use to it. This safety feature is one reason that I wish I had track mode. Even taking it out in the snow I had troubles intentionally getting the rear end to slide out when keeping the accelerator down.

 

[AlanSubie4Life]

Hi Group, new poster here.

We have a Long Range AWD that we acquired in November of last year (2018). I do most of the driving with the M3 and had selected the AWD because my previous (ICE) cars had been AWDs. I always felt they were steadier on wet and icy surfaces.

There's been three incidences with the M3 that make me wonder if its AWD function is the same as my previous cars.

1. The M3 was but a few months old when I parked it on wet soil. Upon leaving I backed the car out and while successful, the rear tended to "slop" around. Thought that was curious.

2. Just recently on a rainy day the car's back end broke traction while making a turn, with the rear end swinging wide. This happened twice on the same day on different pavements, but each time in the rain. The first was at about 10mph at a somewhat odd down hill left turn. The second was on level pavement at about 40mph, and I gave the accelerator just a slight bump while going around a right hand turn. Both these incidences surprised me.

I had not experienced this behavior with previous AWDs.

I recently read an article about the possibility of a two-speed tranny in future BEVs. In the article there was an aside about how Tesla had effectively accomplished the same thing with the M3 AWD. That is, front drive with one ratio and rear drive with a different ratio. One drive for acceleration and the other for highway speeds.

Assuming the car is performing as intended, my experiences suggest that the M3 does not actually function as an AWD, but rather as an either/or drive.

I've seen no web comments on this characteristic, so I'd appreciate any thoughts other users might have.

Thanks,
Mark

There are a lot of threads on this actually. You are correct; as you can clearly see in the roller test linked above, the AWD Model 3 is essentially a "RWD-first" vehicle. (The reason is probably efficiency since the rear motor is more efficient in Model 3.) You can see in every single test that the rear wheels try first without any effort from the front (even the ones with the front wheels off the ground). Quite different from the behavior of the Quattro...

Hopefully at some point they will introduce a Snow Mode which will make the drive a little bit more reassuring in the snow. Some people find it disconcerting as currently implemented, as the rear end tends to step out before catching itself. It's a controversial subject, but hopefully they will do a new mode.

Your experiences are not unusual.

AFAIK the drive ratios in Model 3 are the same front and rear (it's about 9:1). But I don't know that for sure. However, the motor in the rear probably can produce a bit more than 50% more torque or so (I am not sure whether anyone has measured them individually...this is just based on the max power specs from each motor).


I wonder whether those guys have done the roller test on the Raven version of the Model S? I assume that will behave like a "FWD-first" vehicle. Since the efficient motor is in the front of that one... Might be a little better balanced than Model 3 because the rear motor is still more powerful (like in Model 3). I guess we'll see. Would not surprise me if it behaved like "FWD-first."

 

[ewoodrick]

Yes with all the extra instant power the back can slide out a little but will quickly correct itself. The first couple times it was a little concerning but I got use to it. This safety feature is one reason that I wish I had track mode. Even taking it out in the snow I had troubles intentionally getting the rear end to slide out when keeping the accelerator down.

I'll agree here. Traction control doesn't mean that the car won't ever break, it just means that it doesn't tend to get stupid or dangerous. In a turn, it doesn't protect against lateral forces, just rotational slippage. In a turn, I'd expect that the back would slide out, but shouldn't get far. This, I believe would be exemplified the the inability to do donuts.

The traction control isn't proactive, it's reactive.

 

[22522]

Hi Group, new poster here.

We have a Long Range AWD that we acquired in November of last year (2018). I do most of the driving with the M3 and had selected the AWD because my previous (ICE) cars had been AWDs. I always felt they were steadier on wet and icy surfaces.

There's been three incidences with the M3 that make me wonder if its AWD function is the same as my previous cars.

1. The M3 was but a few months old when I parked it on wet soil. Upon leaving I backed the car out and while successful, the rear tended to "slop" around. Thought that was curious.

2. Just recently on a rainy day the car's back end broke traction while making a turn, with the rear end swinging wide. This happened twice on the same day on different pavements, but each time in the rain. The first was at about 10mph at a somewhat odd down hill left turn. The second was on level pavement at about 40mph, and I gave the accelerator just a slight bump while going around a right hand turn. Both these incidences surprised me.

I had not experienced this behavior with previous AWDs.

I recently read an article about the possibility of a two-speed tranny in future BEVs. In the article there was an aside about how Tesla had effectively accomplished the same thing with the M3 AWD. That is, front drive with one ratio and rear drive with a different ratio. One drive for acceleration and the other for highway speeds.

Assuming the car is performing as intended, my experiences suggest that the M3 does not actually function as an AWD, but rather as an either/or drive.

I've seen no web comments on this characteristic, so I'd appreciate any thoughts other users might have.

Thanks,
Mark

Regenerative braking makes assumptions about available traction that are sometimes wrong.

 

[AlanSubie4Life]

Regenerative braking makes assumptions about available traction that are sometimes wrong.

Both the described cases were apparently with accelerator application.

This is just a feature of Model 3 in low-traction situations. As compared to a hypothetical car with equal torque distribution to the wheels (with equivalent tires of course), Model 3 AWD will break traction first in this low-traction situation, since all the torque is being sent to the rear wheels initially. No surprises.

 

[raptor5244]

Lucky duck, I wish I could get the rear to hang out on my M3P.

Maybe they forgot to enable the stability control on your car. Can you spin the wheels as well? Traction Control?

Is is not as crazy as it sounds, my SR+ has the no AP no nag feature. Autosteer never asks me to check in and touch the steering wheel. No errors, no nothing. Just doesn't ask... My M3P+ annoys me every couple minute or so.

 

[niteman1946]

jjrandorin and jyalpert,
Three tires are stock Michelin 235/45 R18 with about 11k miles. Pressure is around 43psi. The right rear is even newer with about 6k miles because of a "non-repairable" nail puncture. Don't think the tires present the problem.

KenC,
I like your suggestion and will give a try (i.e. parking lot). As you see later posters indicate the car is prone to do this but (I think) quick to recover. A few spins in the parking lot should allow the car to square up, if it's capable. And I won't be so quick to get off the power.

AlanSubie-4Life,
Thanks for the comments. Here's the link to the Clean Technica article regarding the different front and rear ratios. Hopefully they have their facts right.
EV Transmissions Are Coming, And It's A Good Thing | CleanTechnica

ewoodrick,
As I mentioned above, I'll try this in a parking lot to see whether the car recovers.

raptor,
I've always considered myself a lucky duck. However, I may have to reconsider.


I'm going to revisit the video on the slip tests to get a better feel for what they are doing. I do feel a bit better about the car and really appreciate all of your responses.

Mark

 

[ewoodrick]

Lucky duck, I wish I could get the rear to hang out on my M3P.

Maybe they forgot to enable the stability control on your car. Can you spin the wheels as well? Traction Control?

Is is not as crazy as it sounds, my SR+ has the no AP no nag feature. Autosteer never asks me to check in and touch the steering wheel. No errors, no nothing. Just doesn't ask... My M3P+ annoys me every couple minute or so.

I remember a YouTube video in the winter from Canada. A gentleman is in a mall parking lot with at least 6 inches of snow. And it seemed to be pretty slick.
Couldn't do a donut.
Floored it from a complete stop. It was hilarious, the car ever so slowly started moving, maybe micro wheel slippage, but watching the video, you would have sworn it was a little old lady trying to drive in that amount of snow.

I found the video and linked to it above. The parking lot stuff is around 3:00 minutes.

 

[raptor5244]

I remember a YouTube video in the winter from Canada. A gentleman is in a mall parking lot with at least 6 inches of snow. And it seemed to be pretty slick.
Couldn't do a donut.
Floored it from a complete stop. It was hilarious, the car ever so slowly started moving, maybe micro wheel slippage, but watching the video, you would have sworn it was a little old lady trying to drive in that amount of snow.

I found the video and linked to it above. The parking lot stuff is around 3:00 minutes.

Thanks, it was funny listening to him try to spin out. I realize the nannies are a good thing but I still feel they should give us the option to turn them off if we want just like in many other cars. Even better would be a sport mode where you can get some yaw before it cuts power. This way you can power out of a drift.

 

[ewoodrick]

Thanks, it was funny listening to him try to spin out. I realize the nannies are a good thing but I still feel they should give us the option to turn them off if we want just like in many other cars. Even better would be a sport mode where you can get some yaw before it cuts power. This way you can power out of a drift.

It's called Track Mode. Available on the 3P.

 

[raptor5244]

It's called Track Mode. Available on the 3P.

Yeah, I know, I own a M3P+ but it does not disable traction control. It puts all the systems into track mode, fans blasting for extra cooling, overclocked AC compressor, increased regen, etc.

It would be nice to have a set of custom drive modes. An intermediate Sport Mode that sits below track mode with "nanny reduction" for when you want to just goose it around a corner real quick. They could also modify the throttle response, steering weight, etc. within a drive mode.

 

[ewoodrick]

I thought that track mode significantly reduced traction control, but yes, doesn't completely disable it.

 

[joelliot]

My experience last winter in the snow and ice is that the stability control of my AWD 3 lets the tail kick out slightly before reining things in. I'm not sure if this is because of rear bias, instant torque, or a permissive stability system, though I suspect it is a combination of all three. I will say that even with the stock all season 18" tires, the system can slog its way up some pretty steep and icy hills. While a little more "slop" than my previous VW or Audi AWD systems, it actually works quite well once you get used to how it behaves. Like many things about my new car, for me, it was just another difference I had to get used to.

 

[AlanSubie4Life]

it was just another difference I had to get used to.

It's definitely different than many AWD systems, as initially it will apply sufficient torque to move the vehicle only to the rear wheels. Then, only if those rear wheels slip will it apply torque using the front motor. See the video linked to above which is a great demonstration of exactly where the torque is applied first, showing this behavior, and how it compares to the Audi system.

This can be disconcerting in snow, since typically you would like to have torque equally distributed to all wheels to reduce the chance of slipping at all. Obviously it depends on your objectives and preferences, but for a driver who wants the car to not slip, it can be disconcerting. After getting used to the way it behaves, it's possible it will feel fine. However, there are quite a few people out there who hope that Tesla could implement an optional Snow Mode which may be less "fun" but more planted.