> Electric cars certainly reduce particulate emissions a lot further, but tire and break wear has become a significant part of particulate emissions.
Doesn't regenerative braking reduce both tire and brake wear?
Doesn't regenerative braking reduce both tire and brake wear?
> Tires on a modern electric car will wear down much slower than in a car with a traditional internal combustion engine. This is due to good traction control. The driver assist systems reduce slipping by utilizing the electric motor's rapid power adjustment. This system is much quicker than in ICE vehicles, where it is based on braking and limiting engine RPM, Liukkula says.
I dunno if anyone's done a good scientific study on this.
How much time do you spend spinning your tyres and braking so hard you skid?
From the skid marks I've seen on the highway, rare skids seem to pull off a significant amount of rubber in one incident.
The heavier car + much better acceleration created more tire wear than any improvements to traction control from faster power response (though I'm not sure intrinsically why that would reduce wear - ICE cars can apply brakes to a slipping tire just as well as an EV, and instant torque doesn't feel like it would do anything positive for tire wear).
Fitting lower rolling resistance tires on ICE cars would provide any of the same benefits that EVs receive.
I suspect "ludicrous mode" will be less likely in semis. Truckers have a pretty good incentive to maximize cost savings; they don't need crazy acceleration like a high-end consumer sedan might want.
That Tesla is pushing run-flats may be why they wear out so ridiculously fast.
As a result, while not skidding, it's easy to accelerate, brake, or decelerate enough to scrub the tires hard enough to wear quickly.
It's pretty well known that Teslas are hard on tires. One benefit is I rarely use brakes instead of regenerative braking. Having AWD does seem to help on that front.
What you're saying, that when you do press the brakes that a computer decides how much to apply regen vs friction, is true, but again, my point is that I don't touch the brakes.
So it sounds like regenerative breaking would covert ~75%-85% of kinetic energy into stored chemical energy. I'd expect to see similar reduction in tire and brake wear as well, maybe even more it probably depends on how break dust is generated, if it has a curve where more is generated with greater breaking force applied, by dropping the force on a break pad to 15% of it's previous value we might see an even greater reduction.
This is all speculation though, I am not a physicist.
Tire wear should be unaffected provided the e-car has a "freewheeling" feature whereby braking is not applied unless the driver hits a brake pedal. If the e-car is set to always run in a regenerative braking mode (brake goes on if driver eases off the "gas" pedal) then the braking will actually increase tire wear.
After all, energy can't be created or destroyed. So if you're storing it in batteries, it's coming out of your forward momentum.
However it would not stop a vehicle on a zero friction surface, as a simple example, so no it doesn’t take away from the friction heat losses on the road.
100%. Brakes do not stop a car, tires do. Brakes just manage the energy. Putting it back into a battery so it can be used to accelerate again is great, but it's still the tires stopping the car.
Now in the case of regenerative braking, the losses from the charging do also dissipate the energy, but most of it goes back into the battery to be used for driving which, over time, is transferred into the tires and the air.
It's important to remember that ideal wheels are not actually moving with respect to the surface they roll over. From the tire's perspective the road is not moving in any direction other than up and down, repeatedly touching the tire and then not touching it again at different points. As long as you maintain static friction when braking and don't start skidding, for ideal wheels, you're not transferring any energy to the tire or to the road.
Now, real tires are not ideal wheels so there's some differences, but those are minor components compared to the majority of energy being dissipated in charging the battery or into heating up/wearing down brakes. And indeed when driving, the majority of loss of energy is from air resistance, not the tires.
Sure, from a lay perspective. Though I stop my car routinely without ever touching the brakes. Even my gas car does a non-trivial amount of braking without using friction pads. But the point stands. Brakes don't touch the road, the tire does, so it matters not at all how you apply force to the wheel, from the perspective of the tire-to-road interface it's all the same.
If we want to have some fun with the physics, brake pads don't use dynamic friction to stop the car, either. Not most of the time, at least. Which is why they last as long as they do.
> Brakes don't touch the road, the tire does, so it matters not at all how you apply force to the wheel, from the perspective of the tire-to-road interface it's all the same.
This is not the case. Brakes (or regenerative braking) absorb the energy of motion into heat or stored chemical energy. The tires are not doing the stopping.
> brake pads don't use dynamic friction to stop the car
This is also incorrect. Brake pads are using almost completely dynamic friction to stop the car. From the perspective of the brake bads the tire is moving and from the perspective of the tire the brake pads are moving. There's no static friction involved there.
The LEAF curb weight is 3,516 to 3,919 lbs, while the Versa is 2,599 to 2,729 lbs
At the midpoint, the LEAF is over 1000lbs or about 40% heavier.
Nissan Rogue (similar sized ICE): 3457# (2WD S) - 3713# (Platinum AWD)
1328 lbs, 37% more.
2020 Tesla Model 3 = 1584 kg curb weight [1]
2019 BMW 320i = 1470 kg curb weight [2]
[1] https://www.cars-data.com/en/tesla-model-3-standard-range-pl...
But that's not really true, either with an EV with regen braking or standard brakes. With standard brakes, it's the friction and heat at the brake pads that causes deceleration. With regen braking, the energy of deceleration is going to charge the batteries.