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Model 3 LR brakes power

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Hi. Ordered a model 3 a few months back and expecting a delivery in the next month or so.

I had a question regarding how powerful the brakes of M3 LR are in comparison to typical 2020-2021 ICE vehicles. Specifically has anyone tested if M3 can decelerate faster or slower than typical ICE vehicles? I am assuming given the heavy weight of the car, it would take less time to stop at lower speeds, and more time to stop at higher speeds, compared to ICE vehicles. Any input would be super helpful.
 
Hi. Ordered a model 3 a few months back and expecting a delivery in the next month or so.

I had a question regarding how powerful the brakes of M3 LR are in comparison to typical 2020-2021 ICE vehicles. Specifically has anyone tested if M3 can decelerate faster or slower than typical ICE vehicles? I am assuming given the heavy weight of the car, it would take less time to stop at lower speeds, and more time to stop at higher speeds, compared to ICE vehicles. Any input would be super helpful.

Why do you think a heavy car would stop better at low speeds, but worse at high speeds? The physics there is proportional, mass only matters because mass makes tires work less well, so more mass is bad, and needs to be compensated for with bigger tires, at any speed.

For a single emergency stop from any reasonable speed (highway or lower) the two main things that affect stopping distance are:

  • The grip of the tires which is a function of:
    • the tire compound and it's friction
  • the relative loading of the tread which is a function of:
    • tire width/size
    • center of gravity of the car
    • vehicle mass
The quality of the calipers/rotors generally doesn't matter for a single emergency stop, if you are stopping repeatedly or from very high speeds then fancier brakes that can deal with extreme heat become important. Anyway all of this is a long way of saying that the Model 3 will stop about as well as any other car on similar tires. The mass to tire size ratio tends to be worse than most ICE vehicles, but the center of gravity is less. The LR models come with especially un-grippy tires when you get the 18" wheel package though.
 
Why do you think a heavy car would stop better at low speeds, but worse at high speeds? The physics there is proportional, mass only matters because mass makes tires work less well, so more mass is bad, and needs to be compensated for with bigger tires, at any speed.
At lower speed friction is dominant due to extra mass. At larger speed inertia is dominant due to extra mass. So less time to stop at slower speed. More time to stop at higher speed.
 
At lower speed friction is dominant due to extra mass. At larger speed inertia is dominant due to extra mass. So less time to stop at slower speed. More time to stop at higher speed.
Nobody cares about time to stop- it's distance. And yes, it's possible to build a vehicle that stops shorter but takes longer, if it can slow down faster at higher speeds (like cars with aero braking do).

Your description is not accurate in any case. "Friction" is not a measure of energy in the way that inertia is. Brakes are all about turning inertia (kinetic energy) into heat via friction, but they are limited in the RATE that they can do so by the coefficient of friction between the tire and the road surface, and the rate impacts distance.

If you can decelerate at a constant 1G, then the only thing that matters is starting speed. Braking is limited by tires more than anything, and a reasonable street tire can do 1G of braking. It can do it at 100 MPH or 10 MPH.

But even if you don't understand all of that, just review the braking distances for a Model 3. 133 feet from 60 MPH. Super similar for other cars in the same category, even across different weights. But review tire reviews on the same car, and you'll see dramatic difference in stopping distances.

Do you think a Semi truck that weighs 80,000 lbs takes 20X as long to stop as a Model 3?
 
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Nobody cares about time to stop- it's distance. And yes, it's possible to build a vehicle that stops shorter but takes longer, if it can slow down faster at higher speeds (like cars with aero braking do).

Your description is not accurate in any case. "Friction" is not a measure of energy in the way that inertia is. Brakes are all about turning inertia (kinetic energy) into heat via friction, but they are limited in the RATE that they can do so by the coefficient of friction between the tire and the road surface, and the rate impacts distance.

If you can decelerate at a constant 1G, then the only thing that matters is starting speed. Braking is limited by tires more than anything, and a reasonable street tire can do 1G of braking. It can do it at 100 MPH or 10 MPH.

But even if you don't understand all of that, just review the braking distances for a Model 3. 133 feet from 60 MPH. Super similar for other cars in the same category, even across different weights. But review tire reviews on the same car, and you'll see dramatic difference in stopping distances.

Do you think a Semi truck that weighs 80,000 lbs takes 20X as long to stop as a Model 3?
Remember the early braking issue where cars were taking 152ft and then OTA update brought it down to 122ft? The interesting thing is with EVs and regen braking there is a some fine tuning that can impact the performance beyond just the tires, pads and rotors.

 
The issue with the breaking when the Model 3 was released was ABS tuning. Nothing to do with regen or anything else EV. Tesla uses complely normal brakes and ABS and tires. Other ICE cars have been recalled for the same reason. Only unique thing was the OTA.
 
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The brakes don't stop the car. The tires do.

For anyone unclear on this, I highly suggest this essay by a guy who has taught SAE master classes on braking systems, designed braking systems for stoptech, ford, and others, and has literally written books on the subject.




Or tl;dr- take two identical LR AWD Model 3 Teslas from the factory.

Test both for braking distance in a stop from highway speed.

Now-
On one- swap the biggest, best, most expensive brake kit you can find.
On the other- swap the tires for Michelin PS4s tires.

Test them again for a stop from highway speed.

Now-
Car 1 will stop in exactly the same distance it stock from highway speeds.
Car 2 will stop dozens of feet shorter than stock from highway speeds.

The brakes don't stop the car. The tires do.
 
Thanks alot for all the useful information that has been shared in this thread. This is very useful information. So it makes sense that most of it comes down the having tires not worn out and with good grip. Do you guys have any suggestion on if the all weather tyres that come with M3 LR are good for daily highway driving in Upstate NY type cold and wet roads? Any particular things I need to look into.

PS: I have never owned (and barely driven) a car with automatic transmission, ABS, power steering and breaks. So tesla will be the first one and I will be doing daily highway drive on it. So far I have only owned a beatup old manual transmission with regular breaks car which I have solely used for city driving.
 
Do you guys have any suggestion on if the all weather tyres that come with M3 LR are good for daily highway driving in Upstate NY type cold and wet roads? Any particular things I need to look into.
If you have been surviving in a 10+ year old car with no ABS, then there is nothing to worry about in a M3 LR. The tires will be fine unless you were running specific snow tires on your previous car.
 
As a general rule-

Dedicated snow/winter tires when it's below 35-40 degrees (and especially with snow on the ground) will be significantly better/safer than any all-season.

Dedicated summer performance tires when it's above 40 (regardless of moisture) will be significantly better/safer than any all season.

They call em all seasons because they suck in all seasons :p

(Note some newer ones are better than they used to be.... Michelins PS-AS4s for example are shockingly good in all conditions except significant snow- and their cross-climate 2s are slightly less good in summer but somewhat better in snow in comparison... but they still won't beat 2 sets of tires for the 2 conditions-- and neither comes stock on a Tesla.)

Last I knew if you're getting 18" wheels you get MXM4 tires which are not great at all... and if you get 19" wheels you get continentals that are somewhat less bad.

For context in non-winter conditions, stopping distances 60-0 are about 133 and 120ish feet on the MXM4s and Contis.

With "real" summer performance tires it's more like 99 feet. Otherwise identical cars, just different tires.


All THAT said- gearcruncher has a point- if you've been driving something without modern safety features you'll probably be "fine" on whatever comes stock on the Tesla... just be aware you've got upgrade options, especially if willing to run 2 sets of tires.
 
Thanks. Yes I have been driving the old regular brake manual transmission car for many years, but only in the city.

A few months back I took a rental for a trip. It was super rainy and cold and super late in night in NY, and I ended up totaling the rental on a highway, as despite applying the brakes very very early, I just couldnt get the car to stop and ended up rear ending another vehicle which was stopping in front of me. I am not sure if it was the road conditions, or the worn out tires of a rental, or water in the brakes, or maybe just me being not experienced with highway driving, but the car just wouldnt stop despite all my efforts.

Since then I have PTSD about highway driving, and keep unnecessarily large following distances when driving on a highway during any trip. The decision to get a Tesla was largely driven by this incident. Hence I was trying to make sure that I have all the information at hand for the time when I take delivery.
 
In my (not comprehensive) experience, rentals have some of the most crappy tires there are.
On average, rental cars are pretty new, and have the factory tires on them. While these cars are not sports cars, they perform mid pack for the average car on the road. Generically saying every single rental has crappy, dangerous tires is not true.

I would highly suggest the OP takes some additional driver training to give them the skills they need and confidence in their car. In just a day you can go from "but the car just wouldn't stop despite all my efforts." to a much more advanced observation on what actually happened, which means you can actually work on solving it when driving. A remarkable percentage of drivers have no idea how effective the brakes are or how to use ABS and never apply the brakes anywhere near fully.
 
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It's just that I almost never keep the original equipment tires on the new cars I buy as I consider them too bad :) I replace them with a high performance all season tire, and I have separate good winter tires since I live where it snows. The MXM4 on my Model 3 drove a total of 3km before being removed.

But I agree with your point, they are not necessarily crappy, they're just not very good. They often favor comfort and low noise instead of traction.
 
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