Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Traction off the line vs at 40mph...

WilliamG

Hinge Fanatic
Apr 20, 2019
6,746
10,652
Seattle, WA
So I’ve noticed in my Model 3 Performance that gunning it off the line to ~60mph results in zero traction loss, even in the wet. I’m sure there’s some power holdback, but I can’t really tell. It’s a bullet. And it’s witchcraft.

However, gunning it at 40-45mph in the wet definitely results in traction loss and some wheel spin straight away.

Does anyone have any insights as to why this is? I’d expect more wheel spin off the line than at 40mph...
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
14,306
18,459
San Diego
So I’ve noticed in my Model 3 Performance that gunning it off the line to ~60mph results in zero traction loss, even in the wet. I’m sure there’s some power holdback, but I can’t really tell. It’s a bullet. And it’s witchcraft.

However, gunning it at 40-45mph in the wet definitely results in traction loss and some wheel spin straight away.

Does anyone have any insights as to why this is? I’d expect more wheel spin off the line than at 40mph...

I’ve never noticed this but it seems possible. I would guess it has to do with one or all of 1) traction control tuning 2) the distribution of torque to front and rear motors vs. time elapsed after accelerator application 3) distribution of torque to front and rear vs. speed and 4) some sort of suspension and drivetrain dynamics due to jerk, which may be ameliorated when doing a launch from 0mph, due to the intentional slow ramp of torque at 0mph.

To first order, max available torque (and acceleration) is constant to about 45mph. However, from 0-3ish mph, the torque and acceleration ramps up “slowly.” So there is inherently less available jerk, for sure, when launching from 0mph. I’ve never instrumented a “launch” from constant 30mph to higher speeds - maybe there is more “available” jerk (though there may be intentional smoothing in that case as well).

Anyway, those are my thoughts for some possibilities. I for sure would not expect this same thing to happen when jamming the accelerator at 60-70mph because there is substantially less torque available there due to having reached the power limit around 45mph.

When the nose of the car dynamically rises on a sudden throttle application, there is a lot of weight transfer going on. Very hand wavy but seems conceivable that it might temporarily break the rear wheels loose if the weight has not fully transferred.
 
Last edited:

WilliamG

Hinge Fanatic
Apr 20, 2019
6,746
10,652
Seattle, WA
Thanks for chiming in, Alan. I wonder if it's because off the line the car has full AWD enabled because it "knows" this is a high-torque scenario, and at higher RPM to save power it's more FWD or RWD biased (it felt RWD-biased in that momentary test). At 70mph up I doubt there'd be any traction loss since it's so much slower from 70mph onward.

In the dry, there's no traction loss at any of these speeds.
 
  • Informative
Reactions: AlanSubie4Life

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
14,306
18,459
San Diego
Maybe the tires have less traction at higher speeds in wet conditions. Probably related to how a car is more susceptible to hydroplaning at higher speeds. Just a guess. Theoretically traction is the same at 0mph as it is 40mph and acceleration/torque is the same on a Model 3 (except for the initial ramp).

This is the simplest explanation and probably the most likely. There have been very heavy rains and flooding in Seattle over the last few days so under those conditions I would expect that you might have some hydroplaning. Maybe @WilliamG can tell us whether it was just wet pavement or pavement with lots of water. Though perhaps a traction difference in wet conditions at speed would still explain it, even if it's not really wet.
 

WilliamG

Hinge Fanatic
Apr 20, 2019
6,746
10,652
Seattle, WA
This is the simplest explanation and probably the most likely. There have been very heavy rains and flooding in Seattle over the last few days so under those conditions I would expect that you might have some hydroplaning. Maybe @WilliamG can tell us whether it was just wet pavement or pavement with lots of water. Though perhaps a traction difference in wet conditions at speed would still explain it, even if it's not really wet.

Thanks, all, for the replies. It was post-rain wet pavement.
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top