Tesla Model 3 Falls Short of a CR Recommendation(consumerreports.org)
consumerreports.org
Tesla Model 3 Falls Short of a CR Recommendation
https://www.consumerreports.org/hybrids-evs/tesla-model-3-review-falls-short-of-consumer-reports-recommendation/
5 comments
This part really intrigued me about the stopping distance:
The Tesla spokeswoman says the company has the ability to update its vehicles over the air. “Unlike other vehicles, Tesla is uniquely positioned to address more corner cases over time through over-the-air software updates, and it continually does so to improve factors such as stopping distance,” she says.
I'm curious the mechanism that makes that possible, or if it's just BS.
The Tesla spokeswoman says the company has the ability to update its vehicles over the air. “Unlike other vehicles, Tesla is uniquely positioned to address more corner cases over time through over-the-air software updates, and it continually does so to improve factors such as stopping distance,” she says.
I'm curious the mechanism that makes that possible, or if it's just BS.
To me, it is disturbing. I get used to the way my vehicle handles, for it to suddenly change because of a software update could potentially be dangerous- but would almost certainly result in a trip to the mechanic for a checkup.
Maybe they have a system for warning owners about these sorts of updates?
Maybe they have a system for warning owners about these sorts of updates?
Well, yes. You get prompted to update your car (you can choose not to). And then after the update is complete, you get a Whats Changed prompt the next time you're in your car. Essentially a patch notes for your vehicle
Good, that makes sense! It would be preferable if they gave you the notes before you installed the update (maybe they do provide a link for it?) Thanks for confirming that, anyway.
For something as major as changing the way a car breaks, do you think "patch notes" (if read at all) are able to properly convey the magnitude of the change?
Yes? My 75D had an entire second shaved off of its 0 - 60 time. I was aware of the change and was able to deal with it just fine...
I'm also not sure what the alternative you're imagining here is. Take it in to a shop just to have them install the update for you? I also don't see how this is any different than changing worn out brakes on an old ICE car. I had the brakes changed in my old '97 Accord, and the difference was noticeable when I pulled it out of the driveway. I think you need to give people a little more credit...
Also, the Whats Changed prompt literally takes up the entire 17in touch screen. It's sort of hard to miss.
I'm also not sure what the alternative you're imagining here is. Take it in to a shop just to have them install the update for you? I also don't see how this is any different than changing worn out brakes on an old ICE car. I had the brakes changed in my old '97 Accord, and the difference was noticeable when I pulled it out of the driveway. I think you need to give people a little more credit...
Also, the Whats Changed prompt literally takes up the entire 17in touch screen. It's sort of hard to miss.
I'm talking about the general populace not only actually reading a prompt but understanding it. Based on how people interact with computers/phones, I do not have a lot of faith in their abilities on this end.
I didn't propose an alternative but there's a huge difference in awareness between a physical in-person "update" vs an OTA update.
For something as serious as changing brake handling, I'm sure they would have some sort of prominent display/cannot continue until you agree prompt but there's always going to be people who do not read things in their entirety. For something that can be destructive as a car, I don't find that acceptable.
I didn't propose an alternative but there's a huge difference in awareness between a physical in-person "update" vs an OTA update.
For something as serious as changing brake handling, I'm sure they would have some sort of prominent display/cannot continue until you agree prompt but there's always going to be people who do not read things in their entirety. For something that can be destructive as a car, I don't find that acceptable.
How do you know that the change is driver-visible? The change might only be for braking hard enough that the anti-lock feature kicks in... which most drivers don't do very often.
Is there an option to revert?
They've already been doing this, back when dual-motor cars first rolled out they had an update that cut the 0-60 from 4.6s to 3.9s.
Def changed the way the car drove, can't say that I minded in that case though.
Def changed the way the car drove, can't say that I minded in that case though.
I can see that for many other areas of handling, but breaking has always seemed the most variable to me. Different road conditions, tire conditions, if the breaks themselves are wet, etc.
I suspect you would get used to it fairly quickly.
I suspect you would get used to it fairly quickly.
Right, but I like to at least pretend to know what the road conditions/ tire conditions/ brake conditions are. Maybe I'm not as clever as I think I am, though :) I try to be a very conscientious and careful driver.
Why would you think it's BS? The Model S gets over-the-air updates all the time; if I recall correctly, they increased the ride height a while ago through an update after a car drove over a metal wotsit, causing a puncture in the battery compartiment and a fire.
They can probably update the settings for the brakes as well, as long as the underlying mechanicals support it.
They can probably update the settings for the brakes as well, as long as the underlying mechanicals support it.
I think the implicit question is "can an OTA somehow improve braking performance - why isn't it optimal already?" not "do Tesla OTAs change other aspects of the car?"
Electric motors and generators are essentially the same thing run in different directions. Run electricity through a motor and it generates motion while putting load on the power. Move a generator and it creates resistance as it extracts electricity. This also answers both how they can change it and why it is not already optimal. Actively using the motors to break causes it to use energy instead of recovering it. Hybrid drivers have long known to break gradually when possible to maximize battery recharge. It is possible they had an electric neophyte as a test driver. Fair enough if they were supposed to test from the perspective of someone new to hybrids and electric cars trying a Tesla as their first.
Not sure if you read the article but what they were testing is pretty much emergency braking from 60mph to full stop.
So the goal is not regenerate the battery (and it doesn't matter if the driver was "an electric neophyte"), it's to brake hard and to repeat the process a couple of times to see if you get brake fade.
From the article: Our testers get a car up to 60 mph, then slam on the brakes until the car comes to a stop. They repeat this multiple times to ensure consistent results. Between each test, the vehicle is driven approximately a mile to cool the brakes and make sure they don’t overheat.
So the goal is not regenerate the battery (and it doesn't matter if the driver was "an electric neophyte"), it's to brake hard and to repeat the process a couple of times to see if you get brake fade.
From the article: Our testers get a car up to 60 mph, then slam on the brakes until the car comes to a stop. They repeat this multiple times to ensure consistent results. Between each test, the vehicle is driven approximately a mile to cool the brakes and make sure they don’t overheat.
Whoops. My mistake for giving into the temptation to segue after my explanation of what I did know.
What does "gradually braking to optimize battery recharge" have to do with an emergency stop?
There are plenty of reasons why you would default to a lower ride height. What would be the purpose of intentionally making your brakes worse than an f150?
I don't think anyone's suggesting it was intentional. Parameters for managing the brakes may just have been set badly, or the anti-locking algorithm written poorly. A possible explanation is they may have optimised it to improve handling while braking.
I never said I thought it was BS. I was curious what the physical mechanism to change the braking characteristics was. If there was no physical mechanism that I assume it's BS.
The car most definitely has software controlled anti-lock braking equipment, and likely has software controlled electric brake cylinders. Both of those things could plausibly be updated via an OTA update.
They improved acceleration via a software update[1] so it's plausible at least.
[1] https://www.engadget.com/2016/11/16/tesla-p100d-software-per...
Edit: why downvotes?
[1] https://www.engadget.com/2016/11/16/tesla-p100d-software-per...
Edit: why downvotes?
My understanding is that car brakes can generally exert more braking force than the tire's grip on the road. A long stopping distance may represent a problem with the anti-lock braking system (which is likely software controlled, and can be updated over the air).
Interestingly, Waymo's self-driving car cannot be updated remotely.[1] As a security measure, Waymo deliberately did not install a data connection to allow that. Probably a good decision.
[1] http://www.documentcloud.org/documents/4458000-Waymo-Driverl...
[1] http://www.documentcloud.org/documents/4458000-Waymo-Driverl...
That's probably also to do with Waymo's cars being developed primarily for ride hailing fleets. With a private ownership model, requiring owners of variable technological faculty to manually apply updates would be less practical.
That was more a PR move than a real security measure.
Signing updates and checking signatures is established technology to certify that updates come from the right place and are not tampered with.
That and the updates are likely >10 GB, so you wouldn't want to download them over mobile data anyway.
Signing updates and checking signatures is established technology to certify that updates come from the right place and are not tampered with.
That and the updates are likely >10 GB, so you wouldn't want to download them over mobile data anyway.
But braking is a solved problem. Apply the maximum force to the tires, until right before the tires begin to slip. Then, reduce the force to prevent slipping. Stay within the "static coefficient of friction", which is higher than "dynamic coefficient of friction".
Alternatively, there's also "let the human do it". (Aka: threshold braking), but most people prefer to have the computer do this task during an emergency.
This algorithm has been used in anti-lock brakes for decades at this point. I'm not sure why it would need an OTA update to improve. Once this algorithm is properly implemented, then the only thing left is to buy better tires and use better rubber to get better grip.
This CR report suggests that Tesla's braking behavior is suboptimal. There's no reason for a smaller, lighter Model 3 to have a worse braking distance than the freaking F-150 truck.
Alternatively, there's also "let the human do it". (Aka: threshold braking), but most people prefer to have the computer do this task during an emergency.
This algorithm has been used in anti-lock brakes for decades at this point. I'm not sure why it would need an OTA update to improve. Once this algorithm is properly implemented, then the only thing left is to buy better tires and use better rubber to get better grip.
This CR report suggests that Tesla's braking behavior is suboptimal. There's no reason for a smaller, lighter Model 3 to have a worse braking distance than the freaking F-150 truck.
> But braking is a solved problem.
That's not to say Tesla haven't decided to re-solve it / implement it themselves anew. The rest of the auto industry has been doing ABS much longer than Tesla has existed.
It's also not a prescriptive algorithm. ABS systems don't stay within the static coefficient of friction; they repeatedly retest the boundary between static and dynamic friction (hence the judder). It's a bit like optimising TCP window size for those familiar with it. There are a bunch of parameters you can tune.
That's not to say Tesla haven't decided to re-solve it / implement it themselves anew. The rest of the auto industry has been doing ABS much longer than Tesla has existed.
It's also not a prescriptive algorithm. ABS systems don't stay within the static coefficient of friction; they repeatedly retest the boundary between static and dynamic friction (hence the judder). It's a bit like optimising TCP window size for those familiar with it. There are a bunch of parameters you can tune.
It also depends what your goal is.
Typical ABS systems typically perform far worse on gravel or sand than non-abs systems for example. It turns out on gravel locking the wheels is usually a better solution because then you start to plough deep into the gravel.
No ABS system could determine that beforehand, since it isn't to know if the gravel is deep (allowing ploughing deep into it) or shallow (where staying on the boundary of static/dynamic friction works better).
Typical ABS systems typically perform far worse on gravel or sand than non-abs systems for example. It turns out on gravel locking the wheels is usually a better solution because then you start to plough deep into the gravel.
No ABS system could determine that beforehand, since it isn't to know if the gravel is deep (allowing ploughing deep into it) or shallow (where staying on the boundary of static/dynamic friction works better).
It could, but it could also be a function of the car's weight (batteries are heavy) and the tires it comes equipped with from the factory. Poor tires will yield poor braking performance due to lack of grip.
But it can't be poor tires, because the Model 3's brakes were proper in the first test (~130 feet stopping distance). The same car with the same tires then had different braking behavior in every test after the first test.
That's just odd.
That's just odd.
I can almost guarantee the problem is caused by the brake pads glazing over. The working surface of a brake pad will become work hardened, which drastically lowers their friction coefficient, once pushed past their designed temperature limit.
The Model 3 (3,800lbs for the long range model) is a fat pig of a car compared to other, conventionally powered cars in its class (3,300lbs for a BMW 3 Series) but this is countered by Tesla fitting them with relatively enormous brakes (14" rotors up front, 13.5" in the rear, larger rotors have more heat absorbing capacity for the pads).
If I had to guess the root cause for this problem, I'd say it is likely down to Tesla's focus on minimizing aerodynamic drag causing a lack of airflow within the wheelwell and across the brakes out the wheel itself. Either that or they chose an absolutely terrible brake pad compound but that just doesn't seem likely in this modern era. Either way, the brakes are getting so hot after a single stop that CR's cooling procedure (a reasonable one I might add) is inadequate to keep the brake pads from drastically overheating. This also explains why braking performance was still compromosed after letting the car cool overnight. The work hardened surface will perform poorly until it is literally ground off from further heavy use of the brakes.
The Model 3 (3,800lbs for the long range model) is a fat pig of a car compared to other, conventionally powered cars in its class (3,300lbs for a BMW 3 Series) but this is countered by Tesla fitting them with relatively enormous brakes (14" rotors up front, 13.5" in the rear, larger rotors have more heat absorbing capacity for the pads).
If I had to guess the root cause for this problem, I'd say it is likely down to Tesla's focus on minimizing aerodynamic drag causing a lack of airflow within the wheelwell and across the brakes out the wheel itself. Either that or they chose an absolutely terrible brake pad compound but that just doesn't seem likely in this modern era. Either way, the brakes are getting so hot after a single stop that CR's cooling procedure (a reasonable one I might add) is inadequate to keep the brake pads from drastically overheating. This also explains why braking performance was still compromosed after letting the car cool overnight. The work hardened surface will perform poorly until it is literally ground off from further heavy use of the brakes.
Can't brake pad material also adhere to the surface of the rotor as well, requiring that they be turned to remove the material? I think that's what people mean when they talk about the rotor being "glazed," a related problem to what you're talking about. This is all a potentially expensive repair.
Usually, when pad material adheres to the rotor, people call that "warped rotors" because it feels like the rotor is warped when braking. It's not usually uniform, I think.
As for expense, brakes are simple and the parts generally cheap, at least for mass-market cars. You can get a full set of pads and rotors for less than $100 from Autozone.
As for expense, brakes are simple and the parts generally cheap, at least for mass-market cars. You can get a full set of pads and rotors for less than $100 from Autozone.
"Warped" rotors, yes, I've heard that term. Not something that comes up in conversation as much as it used to.
They are a lot cheaper today but the cost of rotors varies tremendously depending on the manufacturer and their volume. I gather they turn rotors a lot less than they used to because they're so darn inexpensive to replace, but I'm pretty sure it's still economical for some of the higher-end stuff.
They are a lot cheaper today but the cost of rotors varies tremendously depending on the manufacturer and their volume. I gather they turn rotors a lot less than they used to because they're so darn inexpensive to replace, but I'm pretty sure it's still economical for some of the higher-end stuff.
> I can almost guarantee the problem is caused by the brake pads glazing over.
That's actually a very reasonable explanation. I can't say I'm a car expert, but your logic at least sounds correct.
That's actually a very reasonable explanation. I can't say I'm a car expert, but your logic at least sounds correct.
Most vehicles detect a sharp press to the brakes, and add extra assistive braking force. Thats from the observation that most humans do not apply enough braking force in an accident (potentially because they have never applied that much force before, and don't know how much is 'enough').
It's possible that the tesla software either isn't applying the extra assistive force, either due to incorrect tuning or a bug.
It's possible that the tesla software either isn't applying the extra assistive force, either due to incorrect tuning or a bug.
I'm not sure how true this is. As the car's weight increases so too does the grip, as it's a function of down-force multiplied by the roughly constant coefficient of friction of the tires.
Conceivably, the car's weight may mean that aerodynamic down-force produces a relatively smaller impact on grip, and air resistance a relatively smaller deceleration. But I'm not sure that's enough to account for the difference.
Conceivably, the car's weight may mean that aerodynamic down-force produces a relatively smaller impact on grip, and air resistance a relatively smaller deceleration. But I'm not sure that's enough to account for the difference.
Excellent racing tires have coefficient of friction > 1. That is, a 2-ton car can have more than 2-tons of force applied from the tires.
But most consumer tires have coefficient of friction of less than 1. ~.9 for higher end stuff, but it could be as low as ~.5 or so. Which mean 2-tons of car will lead to LESS than 2-tons of acceleration / deceleration / turning force.
In effect, "more weight is more advantage" is only true if you have a coefficient of friction greater than 1.
But most consumer tires have coefficient of friction of less than 1. ~.9 for higher end stuff, but it could be as low as ~.5 or so. Which mean 2-tons of car will lead to LESS than 2-tons of acceleration / deceleration / turning force.
In effect, "more weight is more advantage" is only true if you have a coefficient of friction greater than 1.
The last line of your post isn't clear.
Since F=MA, A=F/M. Assuming the braking force (F) is μ (coefficient of friction) * Mass * Gravity, thats F=μMG.
Combining those equations you get:
A = μMG / M
And the M's cancel, giving:
A = μG
Therefore the braking distance due to road friction alone (and ignoring aerodynamic downforce effects) is independent of the mass of the vehicle.
Since F=MA, A=F/M. Assuming the braking force (F) is μ (coefficient of friction) * Mass * Gravity, thats F=μMG.
Combining those equations you get:
A = μMG / M
And the M's cancel, giving:
A = μG
Therefore the braking distance due to road friction alone (and ignoring aerodynamic downforce effects) is independent of the mass of the vehicle.
Isn't this neglecting the forward velocity and momentum?
According to theory, the width of a tire has zero effect on tire grip. Race cars and high-performance cars prove this is incorrect: there's a reason they have wide tires (which also cause poorer fuel economy through extra friction). Tires and their interaction with the road are a lot more complex than some simple physics equations.
According to theory, the width of a tire has zero effect on tire grip. Race cars and high-performance cars prove this is incorrect: there's a reason they have wide tires (which also cause poorer fuel economy through extra friction). Tires and their interaction with the road are a lot more complex than some simple physics equations.
Hmm, that makes sense.
Its like the whole "area" doesn't matter as well. I can't help but think that maybe the Newtonian friction model is overly simple sometimes. Surely weight and surface area would have an effect?
But perhaps not really. Or at least, not in a way that's very measurable.
Its like the whole "area" doesn't matter as well. I can't help but think that maybe the Newtonian friction model is overly simple sometimes. Surely weight and surface area would have an effect?
But perhaps not really. Or at least, not in a way that's very measurable.
I think it's definitely overly simple. If it were correct, high-performance cars wouldn't have wide tires. According to Newtonian friction, the contact patch is the same size regardless of the size of the tire. Obviously that's silly; a Lamborghini is not going to get sufficient grip out of economy-car tires, nor would an 18-wheeler. That model completely neglects the complexities of the construction of the tires; they're not like balloons, they're actually semi-rigid.
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I understand Teslas are fairly heavy cars. That explains most of the problem I think.
The Model S is in fact about as heavy as a Ford F150.
However, if this braking result is consistent across all Model 3 vehicles, that's a bit worrisome. I'm also a little concerned with the other issues they had (ergonomics, wind noise, etc). From everyone I know that drives or has driven a Model 3, they've had amazing experiences as far as actual driving
However, if this braking result is consistent across all Model 3 vehicles, that's a bit worrisome. I'm also a little concerned with the other issues they had (ergonomics, wind noise, etc). From everyone I know that drives or has driven a Model 3, they've had amazing experiences as far as actual driving
"this is Consumer Reports, and they have a very good reputation to protect"
CR doesn't have a very good reputation though? I mean... they used to. But their reputation is middling at best now.
CR doesn't have a very good reputation though? I mean... they used to. But their reputation is middling at best now.
Who has better reviews for consumer goods?
Seems like a terrible design choice to make lots of basic adjustments use the touch screen. Adjusting the mirror and AC vents with a touch screen is almost guaranteed to be a terrible experience, especially since people do those often while they're driving.
You frequently adjust your mirror when driving? That's something I do once in a few months (if that), twice if someone drives my car and adjusts the mirrors to fit them.. Perhaps you should adjust your seat instead?
Mirrors? No.
Air conditioning? Yes. On longer drives, the positioning of the sun greatly determines whether or not my AC is running. Radio stations also are frequently changed, as is volume. If someone is talking to me in the passenger's seat, I instinctively turn down the volume of the radio for example.
I personally prefer physical buttons for these various tasks. Physical buttons are always there. I don't have to look at the screen to ensure that I'm on the "correct app" or whatever before trying to fiddle with the AC or volume.
Air conditioning? Yes. On longer drives, the positioning of the sun greatly determines whether or not my AC is running. Radio stations also are frequently changed, as is volume. If someone is talking to me in the passenger's seat, I instinctively turn down the volume of the radio for example.
I personally prefer physical buttons for these various tasks. Physical buttons are always there. I don't have to look at the screen to ensure that I'm on the "correct app" or whatever before trying to fiddle with the AC or volume.
Living in a city, I must manually retract side mirrors when parking on small streets and extend them before driving. Often need to readjust the mirrors each time after extending them.
I take it that you don't drive a car that folds its mirrors when you put it in Park, which is now a common feature.
I share a car with my wife, who is much shorter than I am, so yes
I can only think that their intention is that everything can be updated over the air, this includes all the buttons and controls.
It's certainly a bad thing from a UX perspective. The number of controls in a car / aircraft is a very typical example of why modes are bad. One button for one action is the easiest to learn over the long run, there is a clear mapping in the drivers head of what each of the controls does. They all have different affordances, which is much harder on a touch screen.
However saying that, there's clearly problems with BMW's car UX [0]. Tesla have put a lot of thought into the UX [1] but it seems to be more on a grand scale with specific user cases in mind (your garage magically opening as you approach), rather than the mundane of reducing the number of clicks for the average task.
[0]: https://www.nngroup.com/articles/why-consumer-products-have-...
[1]: https://uxmag.com/articles/tesla%E2%80%99s-groundbreaking-ux...
It's certainly a bad thing from a UX perspective. The number of controls in a car / aircraft is a very typical example of why modes are bad. One button for one action is the easiest to learn over the long run, there is a clear mapping in the drivers head of what each of the controls does. They all have different affordances, which is much harder on a touch screen.
However saying that, there's clearly problems with BMW's car UX [0]. Tesla have put a lot of thought into the UX [1] but it seems to be more on a grand scale with specific user cases in mind (your garage magically opening as you approach), rather than the mundane of reducing the number of clicks for the average task.
[0]: https://www.nngroup.com/articles/why-consumer-products-have-...
[1]: https://uxmag.com/articles/tesla%E2%80%99s-groundbreaking-ux...
It's a terrible design in terms of ergonomics and user experience but it's frankly genius in terms of development timeline efficiency and cost control. Tesla was able to condense hundreds of indididual parts that come from a supply chain involving a dozen plus companies into a single component.
Radios, HVAC controls, gauges, and the fancy dashboards which contain them are among the most expensive parts to develop in terms of both time and money. The amount of time Tesla saved in PPAPs (Production Part Approval Process) alone might be as much as a year and when working with a timeline as aggressive as those demanded by Musk, anything that reduces development time is more valuable than gold.
It's a genius way to reduce the time needed to bring a car to market, the final bill of materials, and the complexity of assembly and installation of such a key component as a dashboard. It's a terrible idea in terms of driver experience but those are the kinds of compromised that must be made to bring something like a Model 3 to market at the promised $35,000 price point.
Radios, HVAC controls, gauges, and the fancy dashboards which contain them are among the most expensive parts to develop in terms of both time and money. The amount of time Tesla saved in PPAPs (Production Part Approval Process) alone might be as much as a year and when working with a timeline as aggressive as those demanded by Musk, anything that reduces development time is more valuable than gold.
It's a genius way to reduce the time needed to bring a car to market, the final bill of materials, and the complexity of assembly and installation of such a key component as a dashboard. It's a terrible idea in terms of driver experience but those are the kinds of compromised that must be made to bring something like a Model 3 to market at the promised $35,000 price point.
I can't decide if this is snark or not. The decisions you make to optimize your processes are irrelevant to me as a consumer. Yes, you have to make calls on compromises but if you don't make the right ones, that's on you.
It's actually not snark. I work in the industry and I legitametely believe Tesla's call to forgo traditional controls is defensible when viewed through this lense. Tesla's current business model is, and has been, 100% dependent on getting the Model 3 to market at the famously touted price of $35,000.
Bringing a car like the Model 3, with all the features promised over the years, into mass production (100k+ per year production rate) within a timeframe required to secure a position in the market where 100k example can be sold necessitates such wild thinking. Yes, it's a terrible design for the driver, but Tesla beat every other manufacturer to the punch by at least 4 years. The "everything is contained in one, basocally off the shelf touchscreen" idea makes part of the ownership experience worse bit it got the Model 3 in consumer's hands at least 1 year earlier than it would have been otherwise and likely shaved a grand or two off the final base price.
I'd never buy a Model 3 because the touchscreen is so offensivley terrible. However, when a quarter million people are willing to put their money down to buy one simply due to the range, pricw point, and expected launch date, then any compromise that helps get the car into their hands as promised, without a revolt among depositors, is "smart" in its own right.
Bringing a car like the Model 3, with all the features promised over the years, into mass production (100k+ per year production rate) within a timeframe required to secure a position in the market where 100k example can be sold necessitates such wild thinking. Yes, it's a terrible design for the driver, but Tesla beat every other manufacturer to the punch by at least 4 years. The "everything is contained in one, basocally off the shelf touchscreen" idea makes part of the ownership experience worse bit it got the Model 3 in consumer's hands at least 1 year earlier than it would have been otherwise and likely shaved a grand or two off the final base price.
I'd never buy a Model 3 because the touchscreen is so offensivley terrible. However, when a quarter million people are willing to put their money down to buy one simply due to the range, pricw point, and expected launch date, then any compromise that helps get the car into their hands as promised, without a revolt among depositors, is "smart" in its own right.
This is an area where Land Rover got things shockingly right.
They put knobs with LCD screens within the larger LCD center panel, and they put tiny OLED screens on the steering wheel buttons.
Tesla's UI design is an obtuse dead end.
https://youtu.be/S6YYun90S8g?t=6m22s
They put knobs with LCD screens within the larger LCD center panel, and they put tiny OLED screens on the steering wheel buttons.
Tesla's UI design is an obtuse dead end.
https://youtu.be/S6YYun90S8g?t=6m22s
I think that is UX done right. Very impressed that they have tactile context aware buttons and knobs. I would pay for something like that in a phone as a skin or a case.
I would say it is clear safety hazard and should prevent such a car from being given the ok by the DOT.
But then again Tesla assumes their cars will be driving themselves anyway so getting distracted trying to adjust the AC should not be a problem...
But then again Tesla assumes their cars will be driving themselves anyway so getting distracted trying to adjust the AC should not be a problem...
> past driving behavior that may have affected the brake system
Could this mean that such a vehicle under test would brake differently than the average driver. Since the brake is constantly being slammed during repeated tests, the software adjusts breaking parameters? Still find it odd to implement such a system, but could explain the inconsistent results.
Could this mean that such a vehicle under test would brake differently than the average driver. Since the brake is constantly being slammed during repeated tests, the software adjusts breaking parameters? Still find it odd to implement such a system, but could explain the inconsistent results.
Since they did more tests the following day and didn't see improved performance, it doesn't seem likely related to thermal limiting in software.
If I were to guess, it would be that in a sudden stop, something inside the brake mechanism heats up so much it bends or deforms, and then doesn't work so well after that.
If my guess is correct, it could be an expensive recall...
If I were to guess, it would be that in a sudden stop, something inside the brake mechanism heats up so much it bends or deforms, and then doesn't work so well after that.
If my guess is correct, it could be an expensive recall...
I can almost guarantee the brake pads glazed over due to overheating. The pad's surface will begin to work harden once a certain temperature threshold is exceeded and that hardened surface has a much lower coefficient of friction than the original unhardened pad. This work hardened material will never return to normal so full braking performance will not be restored until it is ground away by further use of the brakes (light use, you don't overheat them again and make the problem worse).
That explains why the poor braking performance was unaffected by an overnight cooldown. All that said, if the Model 3 is glazing brake pads with a single emergency stop then they need to issue a recall and figure out a fix.
That explains why the poor braking performance was unaffected by an overnight cooldown. All that said, if the Model 3 is glazing brake pads with a single emergency stop then they need to issue a recall and figure out a fix.
The whole brake from 60-0 10 times quickly seems like a stupid metric. Would you rather have shorter stop times, but a design that fails at 15 times? Or a brake that adapts to that load and progressively stops more gently. Any sane driver would adjust.
Seems pretty stupid to evaluate cars on such a weird metric. Sure 60 to 0 or 80 to zero, but what sane person is going to accelerate up to speed as quickly as possible and try again.
Maybe Tesla's doing so poorly because it gets back to 60 quicker than it's competition.
Seems pretty stupid to evaluate cars on such a weird metric. Sure 60 to 0 or 80 to zero, but what sane person is going to accelerate up to speed as quickly as possible and try again.
Maybe Tesla's doing so poorly because it gets back to 60 quicker than it's competition.
> The whole brake from 60-0 10 times quickly seems like a stupid metric
> Sure 60 to 0 or 80 to zero, but what sane person is going to accelerate up to speed as quickly as possible and try again.
Isn't that an argument for CR's test? They explicitly drive 1hr between each braking test so that it's not just "accelerate up to speed as quickly as possible and try again".
Isn't that an argument for CR's test? They explicitly drive 1hr between each braking test so that it's not just "accelerate up to speed as quickly as possible and try again".
I dug for information like that. I only found "Our automotive engineers conduct a series of brake tests from 60 mph to a standstill on wet and dry pavement to measure stopping distances." Do you have a reference for the 1 hour between brake tests?
My reference is: https://www.consumerreports.org/cars-how-consumer-reports-te...
My reference is: https://www.consumerreports.org/cars-how-consumer-reports-te...
Ah, it's not 1 hour, it's 1 mile. It's in the article. Still clearly not "accelerate up to speed as quickly as possible and try again".
"As its name implies, CR’s braking test is meant to determine how a vehicle performs in an emergency situation. The test is based on an industry-standard procedure designed by SAE International, a global engineering association. Our testers get a car up to 60 mph, then slam on the brakes until the car comes to a stop. They repeat this multiple times to ensure consistent results. Between each test, the vehicle is driven approximately a mile to cool the brakes and make sure they don’t overheat."
"As its name implies, CR’s braking test is meant to determine how a vehicle performs in an emergency situation. The test is based on an industry-standard procedure designed by SAE International, a global engineering association. Our testers get a car up to 60 mph, then slam on the brakes until the car comes to a stop. They repeat this multiple times to ensure consistent results. Between each test, the vehicle is driven approximately a mile to cool the brakes and make sure they don’t overheat."
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Tesla's newest car doing badly at a test does not invalidate the test, which has been standard for many years.
The ability to stop quickly at highway speeds is, in fact, something worth testing, and 60-0 stopping time is a great thing to test.
The ability to stop quickly at highway speeds is, in fact, something worth testing, and 60-0 stopping time is a great thing to test.
The folks who test cars at CR are Expert drivers, I was impressed by some YT footage I have seen; if they are saying the brakes are inconsistent then that has nothing to do with the brakes being cooked by hot lapping. Rather it means that lifting off the throttle at the same speed and applying the brakes with the same force, and at the same place on back to back runs will yeild different results. As a racer I can tell you that makes the car Dangerous and no fun at all to drive; if can't trust the car to do the same thing time after time--it's worthless from a pure driving perspective.
I love cars, all kinds of cars. I bought my son a Prius, I even enjoy driving that (just for the unusual driving experience.) I like to see how long I can go on just electric power.
But I'm starting to have real doubts about Tesla. Elon talks a great game, but they've had setback after setback after setback. I have to wonder what the long-term ownership experience will be like.
Good luck to Tesla. I'd love to see them turn out well.
But I'm starting to have real doubts about Tesla. Elon talks a great game, but they've had setback after setback after setback. I have to wonder what the long-term ownership experience will be like.
Good luck to Tesla. I'd love to see them turn out well.
Unlike other vehicles, Tesla is uniquely positioned to address more corner cases over time through over-the-air software updates, and it continually does so to improve factors such as stopping distance,
I'm sorry, but that is complete bullshit. Emergency braking isn't "a corner case", it is one of the primary use-cases of a braking system. Such a statement shows a blatant disregard for the intelligence of their customers, it is shocking.
I'm sorry, but that is complete bullshit. Emergency braking isn't "a corner case", it is one of the primary use-cases of a braking system. Such a statement shows a blatant disregard for the intelligence of their customers, it is shocking.
That’s worrying, and almost as worrying is that Tesla says their braking is much faster. I’m sure plenty of fans will make comments about shorting stock, but this is Consumer Reports, and they have a very good reputation to protect.
I’m not thrilled by this tidbit either.
The Model 3’s stiff ride, unsupportive rear seat and excessive wind noise at highway speeds also hurt its road-test score. In the compact luxury sedan class, most competitors deliver a more comfortable ride and rear seat.