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Model Y Performance Rear Motor
- Thread starter Urbancowboy
- Start date
Electric Steve
Member
And how do the PUP's 21" tires compare to the non-PUP ones?Nope- basic physics- on which you clearly need a lesson. Don't worry, I'm here for you.
(seriously- buckle up- because everything you think you know about brakes is wrong... I know that can be hard to accept- but it remains the case)
Completely false.
Again, I'm here to help: This is the formula for stopping distance-
d=distance to stop
v= velocity of car
u= coefficient of friction between tire and road
g=acceleration due to gravity (9.80 m/s2)
Notice how it does not ask about your rotors or calipers. Because those don't matter.
Also in any other conditions- because physics.
100% wrong. Because, again, basic physics.
Better TIRES=not slamming into the back of another car.
Because the tires stop the car- not the brakes.
Once the brakes are locked (or ABS is engaged), which the smallest factory brakes can easily do, then more brake does nothing at all for you.
But don't believe me, how bout Brembo?
Here's Brembo- a company with a pretty huge interest in SELLING YOU BETTER BRAKES right? Their FAQ addresses why they don't publish stopping distance tests.
Here's Stoptech/Centric- another company with huge financial interest in selling you BETTER brakes.
https://www.apcautotech.com/getmedi...epaper_A2-Brake-Bias-Performance_8-2018_1.pdf
So that's two of the largest upgraded brakes manfacturers both telling you you are wrong.
STILL don't believe em?
Here's Road and Track- surely they know something about cars, right?
How Changing Tires Can Improve Your Braking & Stopping Distances - How Tires Upgrade Your Braking System
I mean- the TITLE akready tells you Why braking is all about tires
the article itself starts out like this:
You know- just like I already told you.
STILL not convinced?
Here's a guy who has literally written books on braking system design
https://www.amazon.com/gp/product/1613250541/
He's also designed braking systems for major OEMs and car makers, as well as teaches SAE master classes on the topic.
GRM Pulp Friction
He explains what each individual part of a braking system does... and does not do.
In fact- the bit that Stoptech is quoting in the previous link?
It's from this essay.
Which explains in detail, with math and physics, why your understanding of brakes and stopping distance is factually and entirely incorrect.
For example-
Since every factory-installing braking system can already lock the wheels (or engage ABS in newer cars)- MOAR BRAKE does literally nothing to reduce stopping distance.
There are many things upgraded brakes CAN do for you (the GRM article describes them in fact, part by part) but "stop the car shorter the first time" is absolutely not one of them- and apart from "feel different" none of them are terribly useful outside of a race track where you'll be repeatedly stopping from triple-digit speeds over and over without the brakes cooling down.
Because physics.
The brakes don't stop the car- the tires do.
Anyone who says differently is selling brake upgrades
(and less honestly than Brembo and Stoptech too)
Hope this helps!
johnmodely
Member
@Knightshade lol I wish I have the time you have. Too bad your too full of yourself to realize I’m not even arguing against the basic physics you keep spewing out from google. Im arguing about your incorrect assertion that bigger breaks have NO impact on how a car stops. No need to keep coming up with more articles on what stops a car.
And yes I did quite well on compsci as well, built a company around both these disciplines that definitely involve way more complex physics than this
And yes I did quite well on compsci as well, built a company around both these disciplines that definitely involve way more complex physics than this
Knightshade
Well-Known Member
Again- most of my replies to you are just a cut and paste from previous corrections of folks who like you didn't understand how stopping works. Very little time investment.
I notice you somehow have had time for three replies to me know while providing literally 0 evidence or sources for your continued denial of the facts though. Weird.
So now you're just making up things that never happened to make yourself look less wrong... because that's:
literally not what I said
and
literally not what your original objection was
I mean- they're only a few posts back in scroll- once again I'm here to help!
What I actually said
Notice how I'm NOT saying "brakes have no impact" I'm saying brakes larger than the stock base model ones do not reduce stopping distance.
Because they don't.
Hell, I specifically point out a way they DO have an impact for track use-- fade resistance.
Which isn't "reducing stopping distance"
it's "maintaining the original stopping distance for repeated illegally-high speed stops over and over without time to cool down"
And YOUR reply was not, as you just claimed, arguing they have "some impact" here it is again-
Not "I'm overstating" or "some impact"
You go on to continue being wrong in writiing:
Which is 100 percent untrue
Because since the stock brakes can engage ABS (you know- that fundamental physics you NOW realize I'm right about?) it's impossible for stronger brakes to stop the car any shorter.
Because physics.
Which you appear to finally admit you misunderstood and I got right....but still desperately flail around for SOME way you weren't totally wrong... and fail there too.
And yes I did quite well on compsci as well, built a company around both these disciplines that definitely involve way more complex physics than this
Given how wrong you've gotten the basic physics in this talk so far... yikes.
Great question! (though these are easily changed later of course)
The Tesla Model Y Wheel and Tire Guide
This reports the 19s come with Conti ProContact RX all seasons... (a good, but not awesome, all season tire)
the optional 20s with Goodyear Eagle F1 tires which are max performance summer tires...and very good ones
The P 21s come wrapped in Pirelli P Zero max performance summers, which are also very good ones.
From head to head testing the P tires are overall better in dry conditions, the Goodyears are better in wet driving....
Specifically in reference to stopping distance though the Pirellis are very slightly better (difference of about 1.6 feet in wet, 3.5 feet in dry)
Full results here:
https://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=218
Regarding future tires (or for someone getting the 19s and wanting the best right away)
The Michelin Pilot Sport 4S is generally considered the best in class tire for street use in non-freezing conditions...(it's what comes on the Performance Model 3) and you can see that against the Pirelli P zero here:
https://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=223
Where the Michelin beats the Pirelli in dry braking by 2.7 feet, and beats it in wet braking by almost 6 feet.
Electric Steve
Member
Ok, so what I got out of this is that the 21" Pirelli P Zero Max "Überturbine" summer performance tires are rather good for what they're made for, better than the 20" Goodyear Eagle F1's "Induction" tires, although perhaps not quite as good as the Michelin Pilot Super Sport. And, so long as we're talking about good weather, they're clearly better than the 19" Continental ProContact RX "Gemini" all-season tires.
Based on this, my plans are pretty much unchanged. I'll go with the tires that came with the car until the weather drops to consistently below 40, at which point I'll swap in some proper snow tires. Then, when it warms up, I'll have to decide between taking my original tires out of storage or perhaps replacing them.
It might be nice to upgrade to those Michelins, but I think my main goal would be to move away from the skinny 21" tires to something with a bit of sidewall so that I don't worry about damaging my wheels.
What do you think?
Knightshade
Well-Known Member
Well.... the 2 sets of wheels/tires sounds solid to me... (I learned to drive in NY, don't let the NC in my profile fool you)
Personally I'd want smaller/lighter wheels on both sets to avoid (or at least reduce chance of catastrophic) pothole damage- especially up north where the freezing cycles cause more of em... (I'd also want a square setup- that wheel/tire link says the PY comes with staggered wheels)... so if it were me I'd see what the market is for selling the 21s and wrap some nice flow-forged 18s or 19s in the PS4s as a summer replacement.
One thing to be aware of, at least on the 3, due to the different brakes on the P, not all 18s for example fit properly as there's kind of an extra lip there... unsure if that's true of the Y but worth keeping in mind at least.
Electric Steve
Member
You've probably seen this video about switching from 20" to 18" Michelin PS4S on the M3 to avoid broken wheels from potholes; it's what's motivating me.
So maybe the Michelins would work in 18" or 19", with appropriate lightweight, flow-forged wheels. This would provide good performance with more resistance to crappy roads and be lighter for better mileage. Also, as you mentioned, getting the same size on front and back means being able to rotate the tires to even out the wear, which would be nice.
It sounds like I need to price out two full sets of tires/wheels. The higher priority is figuring out the snow tires, since by the time I eventually get the car, we'll be at the point where winter is coming.
spsheridan
Member
Sandy Munro shows Model Y front (induction) and rear (permanent magnet) motors and a teardown of several EV motors (including Model 3 at 10:45). Sandy states the Model Y motors look "very very similar to Model 3 motors".
I didn't know there is oil and an oil filter for the gearboxes of the front and back Model 3 & Y motors. How often do those need to be changed?
I didn't know there is oil and an oil filter for the gearboxes of the front and back Model 3 & Y motors. How often do those need to be changed?
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PDACPA
Member
I'm a little reluctant to comment on an emotionally charged discussion, but thought a couple of points may help.
1. Saying the wheels stop the car and not the brakes isn't correct. The braking system is just that, a system. All of the components are involved. This includes the tires, brakes, springs, shocks, etc. For example, on a bumpy road with bad shocks, the car may take much longer to stop. I agree that the tire friction is the primary limiting factor until your brakes get very hot.
2. Larger or more aggressive brakes help very little if at all on the first 0-60 stop. Sronger brakes benefit most when the weaker brakes get hot enough that they become the friction limit (vs the tires).
1. Saying the wheels stop the car and not the brakes isn't correct. The braking system is just that, a system. All of the components are involved. This includes the tires, brakes, springs, shocks, etc. For example, on a bumpy road with bad shocks, the car may take much longer to stop. I agree that the tire friction is the primary limiting factor until your brakes get very hot.
2. Larger or more aggressive brakes help very little if at all on the first 0-60 stop. Sronger brakes benefit most when the weaker brakes get hot enough that they become the friction limit (vs the tires).
Knightshade
Well-Known Member
Except, it literally is.
The tire is the only thing exerting a physical force against the road- and thus the only thing (apart from air friction obviously) slowing the vehicle.
That's the entire point- your deceleration is, 100 percent of the time limited by the friction between tire and road.
As long as your tire is applying the maximum amount of friction it is capable of- which it is if ABS is engaged- then MOAR BRAKES does nothing for you.
Thus, since the even the stock non-P braking system can engage ABS (as can the lowest-end stock braking system of basically any car made in the last couple decades)- upgrading your brakes can not stop you any shorter.
Period. Full stop.
If you're still fuzzy on why, check the last 10 links provided from folks who:
Test cars for a living
Design and build and sell braking systems for a living
Literally teach SAE master classes on braking system design and function.
Who all explain the same in considerably more detail.
The road isn't part of the car of course.
As to shocks- you're moving the goalposts now.
You're moving them from "Can upgraded parts stop the car shorter than stock parts" (which apart from better tires is a definitive no)
to
"Can defective/failing parts lengthen stopping distance" which of course is a yes... if there's a tear in your brake line you might not be able to get to the point of engaging ABS for example and might take longer to stop.
But you won't ever be able to make the car stop shorter than it did originally by putting in a "better" brake line than the factory did.
Because the minimum stopping distance is always limited by the tires. Plenty of things you can do to make stopping distance WORSE than that minimum by changing (or damaging) parts- but nothing you can to make stopping distance BETTER other than better tires.
Because the tires are what stop the car.
Then it's really weird you're getting into the argument at all since that was the core original point under discussion.
Not at all is the correct answer... again on any modern vehicle.
I imagine you can find generations-old cars with ancient factory brakes that can't even lock the wheels in stock form- upgrades on those could certainly help.
But not on anything made at least this century- and I suspect you'd have to go back at least a decade or two more than that to find many substantive examples.
Man....if only I'd mentioned exactly that as the reason they're only useful on the track or in the chase scene of a Jason Bourne movie in my original post...
Oh...wait... I did.
But even then the better brakes can't ever stop you shorter than the smaller brakes did the first time.
They simply maintain that same distance over a greater number of back to back stops without time to cool down.
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Knightshade
Well-Known Member
Very similar != identical of course... .but AFAIK the PNs of the rear DUs are identical to the 3.... (dunno if anyone has compared the front yet?)
If there genuinely is a difference (ie the theory the Y puts out more power) I'd look outside the DU for reasons for it (better wiring between it and the HV system, better cooling from the octovalve system, etc...)
Never, per the official maintenance schedule.
johnmodely
Member
Why do you keep taking black and white logic to a complex system that does not equate to just basic physics you keep repeating? I know this must be the limit of your understanding, but that does not mean there is no additional knowledge of physics going on beyond the basic controlled case you keep saying tires are the only thing limiting the system. You keep thinking im arguing against basics physics, im agreeing with you, just merely stating the system is more complex than your basic case.
Here is an example since you wanted one so bad, and why I made the point that bigger BREAKS ;p do have a material impact on stopping distance, especially when it comes to oh *sugar* moments im about to hit a dear or rear end someone.
1) Bigger brakes / calipars / pads means less foot pressure needed to exert the same stopping force on the rotor, and since we are slow analog beings in a non controlled circumstance this WILL have an effect on how much sooner the car stops.
2) As you mash on the brakes what is actually happening is your converting kinetic energy into thermal energy...THAT is what is stopping the car, and that occurs due to the friction in the caliper and rotor. If you take the whole physical system into context (and im separating many variables and sub systems in this complex transfer of energy going on as the car is actually stoping) the tires have very small fraction of that energy pie. Your point is only relevant at one extreme case when ABS is engaged due to the tires no longer having enough friction to stop the car, which is the ONLY time tires are the limiting variable ( and yes thats nearly 100% of the time in a controlled 0-60 test). Due to the majority of the energy being transferred into the rotor assembly this means the rotor heats up at extremely high speeds, this also means the friction coefficient changes at the same rate (goes down as it heats up). If you plot this coefficient over time on honda breaks vs PORCHAAA BREAKS your will find out a material difference
What this means in laymen terms when you combine 1+2 that from the point you realize something dangerous on the roads you will 1) start stopping the car sooner with higher thermal energy transfer if you have bigger brakes, and 2) that thermal energy transfer will effect the stopping force less over time to the point which the ABS system engages and then the physics of tires takes over. Even if this time scale is milliseconds that still translates to inches/feet over the course of 60-0 and would be the difference between a rear end or not.
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Knightshade
Well-Known Member
Because this literally is black and white logic
The tires are the only thing that physically act against the road
Your minimum stopping distance, every single time is limited by the friction between tire and road.
Just like I explained to you already.
And so did Road and Track...Car and Driver... Brembo...Stoptech....James Walker Jr... and a bunch of others.
Yes, but you keep being wrong about that.
Ah! excellent! this should be terrific!
Unless your leg is somehow crippled- no, it will not.
That isn't "an example" it's "an idea you made up with no sources and no basis in reality"
In fact- the GRM Pulp Friction link I provided earlier debunks this exact idea.
Thanks for confirming you didn't read any of the sources explaining in detail why you're wrong though!
Man that was a messy word salad saying basically nothing at all. Wow.
It's also again fundamentally wrong of course... the force of the tire against the road is what stops the car.
The fact the first law of thermodynamics requires that energy has to GO somewhere is what creates heat- but isn't inherently stopping the vehicle.
Or to quote Pulp Friction again (see the article for details on the math)
James Walker Jr said:Crunching the numbers based on a 275/35R17 tire with a rolling radius of 12.2 inches shows that a force of 942 pounds is generated between the tire and road, opposing the motion of the vehicle
Ladies and gentlemen, this is what stops the car--not the brake pads, not the rotors, not the cool stainless steel brake lines. It's the road reacting against the tire
So... my point on the minimum stopping distance is... only relevant.... in the extreme case of...100% of the time we're discussing....
uh, thanks... I guess?
I already cited an actual test of porsche stock brakes vs the $10,000 upgraded carbon ceramic SUPER HIGH HEAT ones.
Stopping distance, from 100 mph, was the same
Because of course it was- since they had the same tires on both.
FACTS! TRY THEM SOMETIME!
In any event- when brakes do overheat (which they don't in the circusmtances we're talking about) that means your braking distance eventually gets LONGER.
But it won't, and can't, ever get any shorter than it did the first time with stock not-overheated brakes.
On a race track if you're repeating braking from 100 mph+ this matters- as I mentioned in the very first post you incorrectly disagreed with.
In normal non-track life though- it doesn't.
Which, again, was the entire point
Brake upgrades don't stop you any shorter- and don't help you at all outside a race track.
Literally none of that is true- or even makes any sense.
You can tell because the car doesn't actually stop any shorter if you upgrade the brakes but don't change the tires.
johnmodely
Member
@Knightshade thanks for proving to me that you have a complex so many people are riddled with that they have to be right, even in context where they have no professional knowledge. Clearly there is no reason to continue explaining to you how the real world works, you can hide behind your screen and bask in the glory of "proving" me wrong lol
Ill continue to enjoy my Performance Model Y, and know my better brakes have a better chance at not hitting something than your non performance brakes, just like they do in every other performance car and is the reason real engineers put as much work into braking systems as tires.
Oh on a side note want to help me with this, working on my next product and need to choose the right phase margin for this regulator design...clearly you are more versed in physics than me
Ill continue to enjoy my Performance Model Y, and know my better brakes have a better chance at not hitting something than your non performance brakes, just like they do in every other performance car and is the reason real engineers put as much work into braking systems as tires.
Oh on a side note want to help me with this, working on my next product and need to choose the right phase margin for this regulator design...clearly you are more versed in physics than me
Knightshade
Well-Known Member
Well, I'm glad you learned something about yourself- even if you apparently continue refusing to learn about what actually stops a car... unfortunate typo there saying "you have" instead of "I have" though which would've made it fit what actually happened
Even funnier when I cited, among the dozen or so sources all proving you wrong, a brake engineer who not only teaches SAE Master classes on brake design, he has literally written books on the topic
Which is, roughly, infinitely more professional experience as you have with brake systems of course.
here's a link- maybe give it a read if you ever want to correct your gross ignorance on how brakes work and why cars stop-
https://www.amazon.com/gp/product/1613250541/
Especially since you never actually started and the few claims you did make, with no sources or actual facts, were so easily debunked with...ya know... a dozen now sources and actual facts?
I mean, you honestly did a pretty good job proving yourself wrong- credit where it's due....
Ignorance is, of course, bliss.
Except where I cited both Car and Driver and Road and Track having objectively proven you wrong- including testing the stock, and $10,000 factory upgraded, braking systems on the same Porsche 911 and found no improvement in braking distance
Man those fact things are pesky, eh?
Oh on a side note want to help me with this, working on my next product and need to choose the right phase margin for this regulator design...clearly you are more versed in physics than me
View attachment 531226
I'm sure we can guess what your answer would be to apparently any physics problem... the biggest one available is the best, even if it objectively offers no measurable benefit for the use case!
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@Knightshade thanks for proving to me that you have a complex so many people are riddled with that they have to be right, even in context where they have no professional knowledge. Clearly there is no reason to continue explaining to you how the real world works, you can hide behind your screen and bask in the glory of "proving" me wrong lol
Ill continue to enjoy my Performance Model Y, and know my better brakes have a better chance at not hitting something than your non performance brakes, just like they do in every other performance car and is the reason real engineers put as much work into braking systems as tires.
Oh on a side note want to help me with this, working on my next product and need to choose the right phase margin for this regulator design...clearly you are more versed in physics than me
View attachment 531226
I think you should watch this video
Cliffs: "Upgrading your brakes doesn't really make you stop sooner"
Electric Steve
Member
Once the brakes have fully stopped the wheels, it has to come down to the tires. That's physics and there's no avoiding it.
The video is pretty clear about this: "The main advantage of upgrading your brakes is not a shorter stopping distance. The main advantage is resisting brake fade."
This was made obvious when their $450 upgrade brakes not only faded but literally caught on fire, while the $4,500 ones just kept on working. So, no, better brakes won't improve your best-case stopping distance much, if at all, especially if they were fine to begin with, but they sure make a difference in the worst.
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. Having said that, this probably says more about how much the stock brakes suck than how great the replacements are. If your stock brakes are fine, you won't see any change, at least not until fading becomes an issue.
I suspect that the stock brakes on a MY Stealth-P are more like the $450 brakes, in that they're pretty damned good, so the red PUP brakes probably won't improve initial stopping distance at all. Having said that, they might retain their stopping distance better after heavy braking, certainly the sort that you might expect on the track or during an entirely artificial test with repeated braking.
Does this translate to anything under more realistic driving conditions? Would stop and go traffic heat up non-PUP brakes to the point where they fade more than PUP brakes? I don't know.
But this does show that the issue is more nuanced than either side makes it out to be. Brakes do matter, tires do matter. Best case and worst case matter.
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