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Tesla Model 3 Gets CR Recommendation After Braking Update
- colinbartlett 8y ago- const brakingDistance = 152; + const brakingDistance = 133;
- baseethrowaway 8y agobraking
- colinbartlett 8y agooh, right... thank you! (edited)
- mikeash 8y agoconst breakingDistance = warrantyMiles + 1;
- hoffbrau99 8y ago>> const breakingDistance = warrantyMiles + 1; const brakingDistance = warrantyMiles + 1;
- howenterprisey 8y agoRead the chain of comments again
- sirsar 8y agoWoosh
- notjustanymike 8y agoif (autoPilot.active) brakingDistance = null;
- netsharc 8y agoSo, OTA software update improved the brakes (dear commenters, please spell this word correctly). Why not have the brakes with that strength from the beginning? If I were to speculate, could it be because this setting would cause high brake wear on the long run? And, what's stopping them from selectively applying this setting? Heh, Volkswagen would probably have loved this capability a few years ago.
- vvanders 8y ago> If I were to speculate, could it be because this setting would cause high brake wear on the long run? No idea why it wasn't this way in the first place. That said on an EV you'll almost never replace the brakes. On our Model S I only touch the brakes in panic situations or < 2mph to come to a stop. Regen braking cover all other cases sufficiently.
- mikeash 8y agoI doubt it was intentional. It seems that the anti-lock brake system was miscalibrated.
- omarforgotpwd 8y agoSo, Model 3 has regenerative brake (uses magnetic resistance to slow car) and regular brakes that every other car has. I believe the tradeoff / timing about when to switch between the two braking systems was slightly off, favoring more energy efficiency rather than the best stopping distance. When this was pointed out they simply adjusted their algorithm for a better overall tradeoff.
- amluto 8y agoUnless the Model 3 is very different from the other Tesla cars, there is no such tradeoff. In a Model S, regenerative braking is triggered by releasing the accelerator pedal. Mechanical braking is triggered by stepping on the brake pedal. I assume that Tesla just screwed up the antilock breaks. If you push the brake pedal all the way down on a dry road, you’re supposed to get full braking power by a mechanical linkage. No software needed.
- skolos 8y agoDid they do it by reducing use of regenerative braking? Does it mean now that M3's brake pads will wear even more quickly? It looks like they already were wearing off faster than expected [1]. [1] https://www.autoevolution.com/news/tesla-model-3-brake-pads-destroyed-after-nine-miles-of-laguna-seca-124324.html https://www.autoevolution.com/news/tesla-model-3-brake-pads-...
- jimrandomh 8y agoThat link is about brake performance on a race track at speeds greater than 100mph. I'm not sure what "expected" is in that context, and I doubt the results generalize to more normal usage.
- azinman2 8y agoCR article mentions 60mph, not 100.
- jimrandomh 8y agoI was referring to the Autoevolution post, not the Consumer Reports article. It specifically mentions a maneuver at 103.9mph.
- newnewpdro 8y agoPresumably they're comparing their observations to other vehicles they've driven on Laguna Seca. My suspicion is that the model 3 has undersized brakes for a vehicle of its mass. It's an obvious place to cut the costs. edit: To clarify, the autoevolution report noted not only the pads "were cooked" but that the front rotors appeared to need replacing. Typically only the pads will wear out when it's a simple matter of requiring a more track-oriented pad (higher temp range). The rotors do not get worn in the process, though they may need to be machined (AKA turned) to remove non-uniformly deposited pad material. When you've got both front rotors and pads ruined after a few hot laps at the track, your options are basically larger diameter rotors and/or a different rotor material. Putting back the same style rotors with a higher temp pad is only going to eat the rotors even faster than before. These long-range EVs are not light vehicles, they have a very high potential to stress the braking system.
- simion314 8y agoWhat prevents a new update to revert this or cause other safety problem? Pushing updates in a rush is not a good sigh for critical software.
- colinbartlett 8y agoI'd like to think they have some kind of automated CI with a huge warehouse full of cars that automatically drives around and tests everything with each Git push.
- super-serial 8y agoAnd it's a demolition derby where only the cars that survive get to pass on their genes/settings to the next generation on the production line.
- psychometry 8y agoThe cars are full of actual chaos monkeys.
- reaperducer 8y ago>The cars are full of actual chaos monkeys. What a coincidence! Car Full of Chaos Monkeys is the name of my Fountains of Wayne tribute band.
- jonknee 8y agoThey sort of do, it's the general public.
- empath75 8y agoAnd they've only killed a few people so far.
- cjhopman 8y agoIf they did, they wouldn't need the media to find the problems for them. Without CR reviewing every update, how confident can you be that they won't regress the braking?
- ISL 8y agoA question for those in the know: To what extent do other auto manufacturers make this level of in-line changes? As someone who has only ever bought used cars, the prospect of substantial in-line changes for a specific model year is quite daunting. With Tesla, it would appear that they are making substantial changes in build technique/quality/parameters weekly...
- dsfyu404ed 8y agoPerforming code changes/updates whenever a car comes into the dealership is pretty standard practice. OTA updates are a technical capability many manufactures have but I'm not sure the extent to which they're used.
- exhilaration 8y agoMy understanding is that almost no one else does OTA updates because their dealer networks demand that any repairs or updates be performed by dealers. The legacy car manufacturers are (sadly) at the mercy of their dealers.
- benjohnson 8y agoNewer FCA products can update OTA - Our 2015 Dodge Durango updated a month ago.
- avs733 8y agoSo to clarify a bit...maximum/emergency braking like this is not limited by regen or by the hydraulic brakes. It is limited by tires, grip, and weight transfer.
- dpark 8y agoClearly in this case it was limited by a software bug/limitation. Tesla did not push an over the air update that changed the tires, grip, or weight transfer. (Actually, I guess they did change the weight transfer, by increasing deceleration.)
- avs733 8y agooh totally agreed. What I find confounding is that up until now the limit on braking performance appears to not have been tire grip but software.
- minhazm 8y agoIt was an ABS issue for anyone wondering. https://twitter.com/elonmusk/status/998778751767871488?lang=en https://twitter.com/elonmusk/status/998778751767871488?lang=...
- vlozka 8y agoControlling the ABS hydraulic modulator and ABS diagnostic bleed are one of the most dangerous cyber-attacks that can be performed on a car. The fact that these systems are (indirectly) connected to the Internet is irresponsible.
- vlozko 8y agoI'm bothered by the fact that it took Consumer Reports testing to discover this issue and to have it fixed. Where was Tesla's QC on this before all this? The CR break tests don't appear to be anything unusual.
- hoffbrau99 8y ago>> break tests brake tests
- deleted 8y ago[deleted]
- adventured 8y agoThe big automakers collectively ship defective vehicles by the millions as a matter of routine business and have been doing so for as long as there has been an automobile business. They're going to continue doing so. You'll regularly get pieces of mail from companies like Nissan, Ford or Hyundai, telling you to bring your vehicle in, years after they sold it, to fix mistakes. Most of the other automakers will just leave you rolling around in a defective 3400 lbs pile of metal for years until they get to a fix or finally figure out there's a problem. Tesla was able to quickly improve its product with a software update and without inconveniencing its customers. It's a superior solution.
- jonknee 8y agoTesla has recalls as well, like this recent one for a faulty power steering component: https://www.cnbc.com/2018/03/29/tesla-recalls-123000-model-s-cars-over-potential-power-steering-failure-reports.html https://www.cnbc.com/2018/03/29/tesla-recalls-123000-model-s... Rarely are recalls for serious defects (those are usually caught before a model is sold), but they are overall a good thing for safety and long term reliability.
- sunstone 8y agoIt's not quite as bad as it seems. The first high speed stop CR did produced the expected and acceptable result. But when they repeated the test they started to get poor results. Under normal driving conditions you don't often repeatedly slam on the brakes from 60mph. Now this isn't a complete absolution of Tesla under the circumstances but it does go some way to explaining how this software bug got into the wild when it shouldn't have.
- SubiculumCode 8y agoCars are not a Flappy Bird app: Crashing matters. This clearly points to a culture inside Tesla of a lackadaisical concern for product safety testing. I say that as a big fan of Tesla and the overall vision Musk and his companies are pursuing.
- mherrmann 8y ago"We fixed it so it brakes."
- stephengillie 8y ago>In retesting after the software update was downloaded, the sedan stopped in 133 feet from 60 mph, an improvement of 19 feet. Combining from a previous thread[0]: Car distance (feet) Model 3(orig) 152 Model 3 (new) 133 F-150 129 Model X 127 Camry Hybrid 125 F-150 Lariat 119 Chrysler 300S 109 It's noteworthy that the stopping distance is still longer than the heavier Model X. [0]https://news.ycombinator.com/item?id=17124967 https://news.ycombinator.com/item?id=17124967
- woodandsteel 8y agoThe practical question is how good the Model 3 will be when they get production up to the point where the large number of people who want to buy one are actually able to do so.
- mchahn 8y agoI know there is a 99.9% chance that my paranoia is just paranoia, but when I first read this I thought tesla just changed the car's behavior to work better on CR's specific tests. The diesel fiasco has scarred me.