Model Y Performance Rear Motor

[Knightshade]

Although, in this case, they did make some improvement, even though this might not translate to the Tesla. The video shows they got a 5' shorter stopping distance compared to stock brakes, which means that the improved ones (whether they're $450 or $4,500) do make a difference.

Their results presentation is... kinda disjointed there...

They show the "stock" distance at 88 feet in one car (which is actually 11 feet shorter than the $450 upgrade distance)... but then show the stock brakes at 106 feet in the second comparison?

And yet they only get a 5 foot difference from stock with BOTH the 88 and 106 "stock" distance?


Likely you're just seeing differences in the drivers reaction time in that 5 feet.


Here's how you professionally measure braking distance:

Brake Testing Measurement and Accuracy

This insures the "start" of the braking event is always known to the calibrated measuring device regardless of human reaction times and it's measuring in multiple ways and cross checked for validity.


it's the kind of testing the car mags use, like in the example I posted earlier of testing a 911s stock brakes against the $10,000 PCCB brake upgrade Porsche offers where distances were basically identical for both in even 100-0 tests...


That said- sure it's also possible the stock brakes were in terrible shape or something- and ANY upgrade (even likely new OEM parts) would've got you that 5 feet.... the fact the difference was exactly the same with two vastly different replacement brake kits kinda hints that's the actual case.... if the BIGGER ALWAYS STOPS BETTER idea was true the $4500 kit and $450 kit wouldn't show the same 5 feet after all.

 

[Electric Steve]

Their results presentation is... kinda disjointed there...

They show the "stock" distance at 88 feet in one car (which is actually 11 feet shorter than the $450 upgrade distance)... but then show the stock brakes at 106 feet in the second comparison?

And yet they only get a 5 foot difference from stock with BOTH the 88 and 106 "stock" distance?


Likely you're just seeing differences in the drivers reaction time in that 5 feet.


Here's how you professionally measure braking distance:

Brake Testing Measurement and Accuracy

This insures the "start" of the braking event is always known to the calibrated measuring device regardless of human reaction times and it's measuring in multiple ways and cross checked for validity.


it's the kind of testing the car mags use, like in the example I posted earlier of testing a 911s stock brakes against the $10,000 PCCB brake upgrade Porsche offers where distances were basically identical for both in even 100-0 tests...


That said- sure it's also possible the stock brakes were in terrible shape or something- and ANY upgrade (even likely new OEM parts) would've got you that 5 feet.... the fact the difference was exactly the same with two vastly different replacement brake kits kinda hints that's the actual case.... if the BIGGER ALWAYS STOPS BETTER idea was true the $4500 kit and $450 kit wouldn't show the same 5 feet after all.

Yeah, like I said, that 5' difference probably said more about the quality (and condition) of the stock brakes.

I found this video interesting, precisely because it tests the brake pads professionally. This is just pads, not overall braking system, and yet there's a lot of difference.

 

[Knightshade]

That's an excellent video- though it doesn't actually test braking distance at all... it's a test of fade resistance- the very thing upgrading your brakes can have a lot of impact on...

In the videos case they do 15 consecutive stops from 100km (62mph) down to 5 (pretty similar to how you'd initially bed pads in after putting em on- the other video mentions this too)- and then runs the same cycle again (where the results turned out a fair bit better even for the cheapest pad)... also interesting is post-bedding (ie the second test cycle) the OEM pads seems to produce the most consistent results.

(after that they go to wear testing, corrosion testing, noise testing, etc where is pretty far afield from the discussion....)


Speaking of pad testing though- here's a fun link:


https://www.justnet.org/pdf/EvaluationBrakePads2000.pdf

National Law Enforcement and Corrections Technology Center did extensive testing of brake pads on police service vehicles... (Ford Interceptor and Chevy Impala as they were the 2 most common police vehicles at the time of testing)


They actually explain why they don't offer any kind of "Here's what 1 panic stop with different pads looks like" testing-

Note: When braking to a targeted deceleration rate, where the speed of the vehicle at brake application is the same, the stopping distance should also theoretically be the same, making any measurement of stopping distances irrelevant

And as we know from previous cited sources- the maximum targetable deceleration rate is always dictated by the friction of the tire against the road. Thus why as long as you can lock the tire (or engage ABS) it's impossible to stop any "shorter" with MOAR BRAKE- since your deceleration rate will be the same- the max the tire is capable of- every time.

Instead they're testing things like fade resistance, wear resistance, pedal feel, etc...all the things that, unlike normal stopping distance, changing brake parts can change.


Interestingly in their fade test they do essentially 20 high speed stops (5 in a row, couple minute pause, 5 in a row, pause, 5 in a row, pause, 5 in a row) then average it all together....

Napa apparently made garbage pads for these cars... because excluding them from say the Ford results you see all 12 of the other pads all within like 1% of the average distance (roughly 2 feet in a ~185 foot stop)...and nothing beat the stock pads by even as much as 1%.... but the Napa pads took 196 feet....WAY above average of the rest.... On the chevy the Napa pads did even worse, taking over 20 feet longer than the OEM pads did.... and once again nobody beats the OEM pads by even as much as 1% (and only 1 brand beats em at all, by a little under -1- foot)

 

[Electric Steve]

That's an excellent video- though it doesn't actually test braking distance at all... it's a test of fade resistance- the very thing upgrading your brakes can have a lot of impact on...

In the videos case they do 15 consecutive stops from 100km (62mph) down to 5 (pretty similar to how you'd initially bed pads in after putting em on- the other video mentions this too)- and then runs the same cycle again (where the results turned out a fair bit better even for the cheapest pad)... also interesting is post-bedding (ie the second test cycle) the OEM pads seems to produce the most consistent results.

(after that they go to wear testing, corrosion testing, noise testing, etc where is pretty far afield from the discussion....)


Speaking of pad testing though- here's a fun link:


https://www.justnet.org/pdf/EvaluationBrakePads2000.pdf

National Law Enforcement and Corrections Technology Center did extensive testing of brake pads on police service vehicles... (Ford Interceptor and Chevy Impala as they were the 2 most common police vehicles at the time of testing)


They actually explain why they don't offer any kind of "Here's what 1 panic stop with different pads looks like" testing-





And as we know from previous cited sources- the maximum targetable deceleration rate is always dictated by the friction of the tire against the road. Thus why as long as you can lock the tire (or engage ABS) it's impossible to stop any "shorter" with MOAR BRAKE- since your deceleration rate will be the same- the max the tire is capable of- every time.

Instead they're testing things like fade resistance, wear resistance, pedal feel, etc...all the things that, unlike normal stopping distance, changing brake parts can change.


Interestingly in their fade test they do essentially 20 high speed stops (5 in a row, couple minute pause, 5 in a row, pause, 5 in a row, pause, 5 in a row) then average it all together....

Napa apparently made garbage pads for these cars... because excluding them from say the Ford results you see all 12 of the other pads all within like 1% of the average distance (roughly 2 feet in a ~185 foot stop)...and nothing beat the stock pads by even as much as 1%.... but the Napa pads took 196 feet....WAY above average of the rest.... On the chevy the Napa pads did even worse, taking over 20 feet longer than the OEM pads did.... and once again nobody beats the OEM pads by even as much as 1% (and only 1 brand beats em at all, by a little under -1- foot)

The maximum deceleration depends on the tires, but as these tests show, it's easy to fall far short of that maximum. And this is what actually matters in the real world.

When I hit the brakes, I want to be able to stop with a consistent, moderate amount of force, unlike those cheap pads shown in the video, where you had to press twice as hard when they're hot.

When I have to brake hard to avoid an accident, I want to have as close to that maximum deceleration as possible, which means resisting fading and corrosion.

And corrosion is definitely a big issue for the Tesla because the brakes aren't used all that much under normal circumstances. This has been confirmed by videos of M3 maintenance, where the brakes don't get enough heat and friction to burn off the road crud, so they develop some rust.

For that matter, I'd really, really like to avoid catastrophic failure. I've had brake failures with my old Ford Explorer and Chrysler Town & Country, and it was scary. I'm not happy I lived through these incidents, but I'm glad I lived.

So, in the end, I still don't know whether the PUP brakes will make a big difference in my life, but I don't really regret ordering them, although I may well wind up regretting the skinny tires that are part of the package. I don't think that, on the whole, it's fair to say that only the tires matter. The tires do matter, but they're not necessarily the weakest link.

 

[phantasms]

The fact that owners keep asking for a software upgrade to Performance sounds like a missed opportunity for Tesla.

Yes!

My god Please Tesla PLEASE take my money already! Please!!!!! Arghhhh!!!!!

ok...I'm done. lol

 

[Knightshade]

The maximum deceleration depends on the tires, but as these tests show, it's easy to fall far short of that maximum. And this is what actually matters in the real world.

...they don't though.

Unless you're stopping 10 times in a row from like 100 mph without cooling down the brakes in between.

When I hit the brakes, I want to be able to stop with a consistent, moderate amount of force, unlike those cheap pads shown in the video, where you had to press twice as hard when they're hot.

Yes... when you overheat your brakes they can fade.

This doesn't happen in normal real life driving though.

It happens on race tracks (or maybe if you were towing a heavy trailer down a mountain in a car that doesn't already have regen braking I suppose)

When I have to brake hard to avoid an accident, I want to have as close to that maximum deceleration as possible, which means resisting fading and corrosion.

It really doesn't, unless you've ALREADY just SLAM THE BRAKE HARD braked like 5-10 times right in a row in the last couple minutes already before this braking event.

In which case, if you're not on a race track, you probably shouldn't be driving a car if you find in NORMAL driving you repeatedly slam hard on the brakes at speed over and over and over... (especially in an EV where you rarely need to even USE the brakes at all thanks to TACC and regen)

And corrosion is definitely a big issue for the Tesla because the brakes aren't used all that much under normal circumstances. This has been confirmed by videos of M3 maintenance, where the brakes don't get enough heat and friction to burn off the road crud, so they develop some rust.

That'll be true regardless of your pads though... it's easy enough to avoid by intentionally doing a hard braking event periodically- I mean put a repeating reminder in your phone if need be.

(this is in reference to rusting on the disc surface... if you mean like the old rotor hat rust issue that's fixed with high temp brake paint and would NOT be fixed by using the brakes more, thread on that here)

Dealing With Model S Brake Rotor Hat Rust

For that matter, I'd really, really like to avoid catastrophic failure. I've had brake failures with my old Ford Explorer and Chrysler Town & Country, and it was scary. I'm not happy I lived through these incidents, but I'm glad I lived.

You seem really focused on issues that only came up in an abuse test of really garbage $20 aftermarket brake pads.

Good news for you then- those not only aren't the OEM pads that come on ANY Tesla- they're AFAIK not even available for Teslas.... so you won't be tempted by them to save a few bucks.


If this is a major concern- just buy OEM pads. P vs non-P won't make any difference here (if it did you'd have the majority of Tesla owners with failing brakes- since most Teslas aren't Ps)

So, in the end, I still don't know whether the PUP brakes will make a big difference in my life

Outside of a race track? The only big difference they may make is limiting your choice of aftermarket wheels... (I'm unsure if the Y has the same limitation the 3 does here- on the 3 PUP you have a lot of wheels that won't work because of the extra lip on the PUP brakes)

I don't think that, on the whole, it's fair to say that only the tires matter. The tires do matter, but they're not necessarily the weakest link.

For normal braking distance? They're the only part of the car that matters.

If still unclear go back and read the previous dozen+ sources from professional car mags, brake system designers, brake engineers, and basic physics formulas that all explain that.

I especially suggest this one, which explains in detail what each individual part of a braking system does, and does not do for you if you upgrade it- and why none of them will, or even can reduce your normal stopping distance:

GRM Pulp Friction

 

[Electric Steve]

...they don't though.

Unless you're stopping 10 times in a row from like 100 mph without cooling down the brakes in between.




Yes... when you overheat your brakes they can fade.

This doesn't happen in normal real life driving though.

It happens on race tracks (or maybe if you were towing a heavy trailer down a mountain in a car that doesn't already have regen braking I suppose)




It really doesn't, unless you've ALREADY just SLAM THE BRAKE HARD braked like 5-10 times right in a row in the last couple minutes already before this braking event.

In which case, if you're not on a race track, you probably shouldn't be driving a car if you find in NORMAL driving you repeatedly slam hard on the brakes at speed over and over and over... (especially in an EV where you rarely need to even USE the brakes at all thanks to TACC and regen)






That'll be true regardless of your pads though... it's easy enough to avoid by intentionally doing a hard braking event periodically- I mean put a repeating reminder in your phone if need be.

(this is in reference to rusting on the disc surface... if you mean like the old rotor hat rust issue that's fixed with high temp brake paint and would NOT be fixed by using the brakes more, thread on that here)

Dealing With Model S Brake Rotor Hat Rust





You seem really focused on issues that only came up in an abuse test of really garbage $20 aftermarket brake pads.

Good news for you then- those not only aren't the OEM pads that come on ANY Tesla- they're AFAIK not even available for Teslas.... so you won't be tempted by them to save a few bucks.


If this is a major concern- just buy OEM pads. P vs non-P won't make any difference here (if it did you'd have the majority of Tesla owners with failing brakes- since most Teslas aren't Ps)




Outside of a race track? The only big difference they may make is limiting your choice of aftermarket wheels... (I'm unsure if the Y has the same limitation the 3 does here- on the 3 PUP you have a lot of wheels that won't work because of the extra lip on the PUP brakes)




For normal braking distance? They're the only part of the car that matters.

If still unclear go back and read the previous dozen+ sources from professional car mags, brake system designers, brake engineers, and basic physics formulas that all explain that.

I especially suggest this one, which explains in detail what each individual part of a braking system does, and does not do for you if you upgrade it- and why none of them will, or even can reduce your normal stopping distance:

GRM Pulp Friction

That last page of that Pulp Friction article says it all: GRM Pulp Friction Page 5

 

[Knightshade]

That last page of that Pulp Friction article says it all: GRM Pulp Friction Page 5

Indeed it does....

Regardless of your huge rotor diameter, brake pedal ratio, magic brake pad material, or number of pistons in your calipers, your maximum deceleration is limited every time by the tire to road interface.

That is the point of this whole article. Your brakes do not stop your car. Your tires stop the car.

So while changes to different parts of the brake system may affect certain characteristics or traits of the system's behavior, using stickier tires is ultimately the only sure-fire method of decreasing stopping distances.

it's just after that it describes reasons one might still wish to make changes to their brakes- Specifically- "feel" which he covers in items 1 and 4 (driver tuning and compliance) and fade resistance (generally a track only concern) that he addresses in 2 and 3.


Depending on the driver even those who do track their cars might find the P brakes needing more work in one or more of those areas... (MPP developed their own larger brake kit for example to handle drivers who fade even the P brakes at the track... and some folks have moved to stainless brake lines for better compliance feel... none of these can reduce street stopping distance of course but can make significant changes to feel/behavior under heavy track use)


For street only, there are some downsides to the P brakes... mostly minor but worth noting- at least these are all true for the 3P brakes I'd be mildly surprised if most/all aren't true on the YP as well-

More limited choice of aftermarket wheels due to extra raised hub lip
More expensive to replace parts if you ever need to (again prob. a long time before you'd care anyway)

I also wanna say I saw a note a while back pad replacement was a little more work on a P, but can't find the reference right now- and honestly unless you drive like a maniac you won't need to replace pads on any Tesla until you're well past the # of miles the average american keeps a new car for anyway

 

[Electric Steve]

Indeed it does....




it's just after that it describes reasons one might still wish to make changes to their brakes- Specifically- "feel" which he covers in items 1 and 4 (driver tuning and compliance) and fade resistance (generally a track only concern) that he addresses in 2 and 3.


Depending on the driver even those who do track their cars might find the P brakes needing more work in one or more of those areas... (MPP developed their own larger brake kit for example to handle drivers who fade even the P brakes at the track... and some folks have moved to stainless brake lines for better compliance feel... none of these can reduce street stopping distance of course but can make significant changes to feel/behavior under heavy track use)


For street only, there are some downsides to the P brakes... mostly minor but worth noting- at least these are all true for the 3P brakes I'd be mildly surprised if most/all aren't true on the YP as well-

More limited choice of aftermarket wheels due to extra raised hub lip
More expensive to replace parts if you ever need to (again prob. a long time before you'd care anyway)

I also wanna say I saw a note a while back pad replacement was a little more work on a P, but can't find the reference right now- and honestly unless you drive like a maniac you won't need to replace pads on any Tesla until you're well past the # of miles the average american keeps a new car for anyway

I'd think that the biggest argument against taking the PUP with the P is the lowered suspension and skinny tires. If you drive over terrible roads, which I definitely do (albeit at low speeds), then there's a risk of damaging them, and that gets expensive fast.

The one thing I want to repeat here is that, while no brakes are going to stop your car faster than the tires can, some brakes will better retain that stopping ability and the amount of pressure necessary on the pedal.

The irony is that, in my test drive on the M3, I barely even touched the brakes, and then only to test them out. With a Tesla, you may not use the brakes much at all, but when you do, it's because you really need them.

 

[Knightshade]

I'd think that the biggest argument against taking the PUP with the P is the lowered suspension and skinny tires. If you drive over terrible roads, which I definitely do (albeit at low speeds), then there's a risk of damaging them, and that gets expensive fast.

The one thing I want to repeat here is that, while no brakes are going to stop your car faster than the tires can, some brakes will better retain that stopping ability and the amount of pressure necessary on the pedal.

Sure... but that's only going to be relevant on a race track, since in normal/legal public-road driving you're not going to fade the brakes.

The irony is that, in my test drive on the M3, I barely even touched the brakes, and then only to test them out. With a Tesla, you may not use the brakes much at all, but when you do, it's because you really need them.

Exactly.

In a normal car there's a few (pretty rare for most) situations where you MIGHT be able to fade brakes on public roads... I mentioned earlier if you're say, driving down from a very high mountain elevation as an example where you have to very frequently brake and either can't, or don't know how to, engine brake.... In a Tesla though regen takes care of this quite easily so even then you're not gonna have heat concerns at all, even for an emergency stop.


This is also why you've got Tesla owners out there (on heavier cars like the Model S even) going 200,000+ miles on the original brake pads.

 

[MrTemple]

My MY Long Range has the 990 rear motor. VIN 36000, 8th char E, built August 15, 2020.

 

[Knightshade]

Looks like they switched the non-P to the 990 a lot quicker on the Y than they did on the 3... (and reports are the SR 3 is being switched to the 990 too based on some government paperwork in the EU)

 

[MrTemple]

Looks like they switched the non-P to the 990 a lot quicker on the Y than they did on the 3... (and reports are the SR 3 is being switched to the 990 too based on some government paperwork in the EU)

I'm glad! Means my VIN is the non-performance, which makes my insurance a lot cheaper!

And from what I've read, after speed-boost (which I'm not sure I'd pay even $1k for on my LR, as it's still a rocket ship!), it's only a couple/few tenths of a second difference over 0-60, which is effectively imperceptible.