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Braking distance concern by Consumer Reports

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Finally, Musk suggested in a tweet last week that the company would make the Model 3’s braking performance the best in its class. Although this update improved the car’s stopping distances, the braking performance is not class-leading.

So, the question is will there be further improvements in software?

Will there be further improvements in hardware?

Will Tesla get Model 3 braking to be best in class?

I personally find it hard to believe they put honkin big rotors/calipers on there keeping us from using 17" wheels on the rear and still don't have awesome braking distances. I'd have to think they can tighten up the numbers some.
 
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I'd suggest all brake test reporting should also include reaction time and distance covered and therefore show

reaction distance + stopping distance = total distance to stop

This might help keep people's perception of stopping distance closer to reality.
(seems to me most never consider reaction time/distance covered)

PS - it would also be nice to see how different tires perform.
(and tire sizes - even just estimated % change would be helpful)
 
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So, the question is will there be further improvements in software?

Will there be further improvements in hardware?

Will Tesla get Model 3 braking to be best in class?

I personally find it hard to believe they put honkin big rotors/calipers on there keeping us from using 17" wheels on the rear and still don't have awesome braking distances. I'd have to think they can tighten up the numbers some.
Tesla Principal - continuous improvement
- expected with software, right?
- hardware is also being improved - [many without notice which causes stress for some]

- lesson? don't buy what you don't want]
- wait for the "best" - may be a never ending wait.

- CR can't complain enough, can they? give us back our model year changes, PLEASE, PLEASE -
-- Lesson? people are not smart enough to use AutoPilot nor smart enough for continuous improvement business model

- Just follow the "Leader GM" can you say IGNITION SWITCH or AIR BAG
-- god, why can't Tesla just be perfect !?!?:eek: please god, I want to know, now!

SIDE NOTE: CR guys must get paid by the word, right?
I'm missing something - not that - I should get paid by the word !:eek: </END>
 
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So, the question is will there be further improvements in software?

Will there be further improvements in hardware?

Will Tesla get Model 3 braking to be best in class?

I personally find it hard to believe they put honkin big rotors/calipers on there keeping us from using 17" wheels on the rear and still don't have awesome braking distances. I'd have to think they can tighten up the numbers some.

This CR thing was a weird case because it was about poor computer code causing issues with repeated stops- it wasn't a physical problem, it was a software one. It wasn't an "improvement" so much as getting incorrect calibration fixed.

Hardware wise-You seem unclear about what actually stops the car- big rotors don't. The brakes don't.

The tires do.

If you want to stop shorter, dump the crap all-seasons the Model 3 comes with and get some Michelin Pilot Sport 4s tires.

I strongly recommend this article to anybody who thinks a big brake kit shortens braking distance-

GRM Pulp Friction

It explains in detail what each part of a vehicles braking system does, and does not, actually do, and what upgrading each element of the system can, and can't do... and why ultimately the only sure way to stop a car shorter is to put stickier tires on it.
 
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PS - it would also be nice to see how different tires perform.

Tesla did share that information: "Tesla’s own testing has found braking distances with an average of 133 feet when conducting the 60-0 mph stops using the 18” Michelin all season tire and as low as 126 feet with all tires currently available."

So better tires made a 7 foot difference, or ~5%. (That was before the software update, the results could be different now.)
 
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Hardware wise-You seem unclear about what actually stops the car- big rotors don't. The brakes don't.

The tires do.
Your article is 25 years old. The physics remain the same but tech marches on and you have to know car details.

Since we know that the stock car can reach 60 mph in 4.5 seconds the tyre grip must be at least 0.9 G, and actually a fair bit more because the 0 - 60 time is power limited. Then remember that the car has to be engineered to stop according to its maximum speed and gross weight, and to accommodate speedster types who might get in trouble if the rotors or pads overheat.

Lastly but not least, I presume that the car is designed to tow.
 
Summer tires stop faster in wet conditions than all season tires. I’m not sure about mud but it seems silly to worry about such a rare use case.
133 feet is close to what every other car gets when equipped with all season tires. The cars getting much better distances are using summer tires.
 
This thread is insane. I can only imagine adult led OEMs are adding “release before completing safety system development” to their product plans so they can meet Tesla’s new innovative standard of ‘improving the vehicle’ after delivery.

Surreal.
 
Your article is 25 years old. The physics remain the same but tech marches on and you have to know car details.

As you say- the physics don't change- so not sure the age of the article has anything to do with anything.

Which part of it is no longer factually/scientifically accurate do you think?


Y
Since we know that the stock car can reach 60 mph in 4.5 seconds the tyre grip must be at least 0.9 G, and actually a fair bit more because the 0 - 60 time is power limited. Then remember that the car has to be engineered to stop according to its maximum speed and gross weight, and to accommodate speedster types who might get in trouble if the rotors or pads overheat.

As evidenced from folks who've taken model Ses on the track, stock tesla brakes are absolutely not designed for speedster types who overheat rotors and pads.

That simply doesn't happen in normal street driving where you're likely to make more than ONE hard panic stop at time.

Likewise- weight isn't an issue.

As long as the brakes can lock up the wheels (or engage ABS might be a better way to put it)- which basically all factory brakes have been able to do on all western production cars for decades now- bigger brakes do literally nothing to improve braking distance.


If you'd like I can quote you Brembo, Stoptech, Motor Trend, Car and Driver, and tons of other industry sources telling you the same thing.

Hell- I did. The guy whose article I linked literally writes books and teaches SAE master classes on brake system design (as well as doing brake design engineering for Stoptech, Ford, and others).

The brakes don't stop the car- the tires do.
 
This thread is insane. I can only imagine adult led OEMs are adding “release before completing safety system development” to their product plans so they can meet Tesla’s new innovative standard of ‘improving the vehicle’ after delivery.

Surreal.

That point seems to get lost in the shuffle. Sure, OTA updates can be a great feature. When they are used to push out software that the car should have had before it even left the factory? Not quite as great.
 
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So, the question is will there be further improvements in software?

Will there be further improvements in hardware?

Will Tesla get Model 3 braking to be best in class?

I personally find it hard to believe they put honkin big rotors/calipers on there keeping us from using 17" wheels on the rear and still don't have awesome braking distances. I'd have to think they can tighten up the numbers some.
Better tires? CR tested with the stock 18's, which are not as good as the 19s for stopping. I believe Edmunds recorded a ~5ft improvement in stopping distance when using the OEM 19s.
 
They let the car sit overnight and when they tested it again the next day it still failed. This was done with multiple cars.

The car didn’t ‘fail’, it simply took longer to come to a stop when heavy braking was applied in close succession than is expected or normal for a car in its category, but it always stopped.

TWO cars. While technically two can be categorized as multiple, the term is usually reserved for larger numbers like at least 4 or 5.
 
This thread is insane. I can only imagine adult led OEMs are adding “release before completing safety system development” to their product plans so they can meet Tesla’s new innovative standard of ‘improving the vehicle’ after delivery.

Surreal.
I think you're missing the point. Every car manufacturer finds bugs after the car is released, which until now generally required a trip to the dealer. Given you'd require multiple panic stops in a row to figure out this braking problem, I'm not surprised Tesla didn't see it during development. 1)you'd have to test sequential panic stops, which is not a normal driving experience, 2) you'd have to notice that the subsequent stops were 20 feet longer (we aren't talking brake failure here). The story here is really how fast the problem was fixed at the end user. I find it an exciting development and worthy of praise.
 
It appears the Model 3's ABS braking would work as designed the first time an emergency braking scenario occurred, but then that event caused it to behave differently in subsequent emergency braking scenarios. Something to do with the ABS calibration algorithm. Its sort of surprising that Tesla didn't catch this fact in their braking tests, perhaps they only ran one or two braking tests per test car. Made a video explaining what happened with the ABS calibration algorithm and the edge case that caused the inconsistent braking problem.
 
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