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Braking distance concern by Consumer Reports

Discussion in 'Model 3' started by SoCalDude, May 21, 2018.

  1. SoCalDude

    SoCalDude Member

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    Does any current M3 owners feel that the cars braking capabilities are any less capable vs. any other car that you drive?

    Tesla shares hit by Consumer Reports criticism

    From Consumer Reports...
    Tesla's stopping distance of 152 feet when braking at 60 mph was far worse than any contemporary car tested by the magazine and about seven feet longer than the stopping distance of a Ford F-150 full-sized pickup.

    Responding, a Tesla spokesperson said: "Tesla's own testing has found braking distances with an average of 133 feet when conducting the 60-0 mph stops using the 18" Michelin all season tire and as low as 126 feet with all tires currently available.
     
    • Informative x 3
  2. bdy0627

    bdy0627 Active Member

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    I don't have one but can't imagine Tesla would have known about this and still released the car with such poor braking performance. This will get fixed very quickly I'm sure.
     
  3. xav-

    xav- Active Member

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    I have raised this a dozen times here.. Often dismissed...

    I am thinking of doing a live test and compare my model 3 / sport wheels against my Chevy volt.

    Bad braking is the main issue with the car IMO. I think this needs a fix.
     
    • Informative x 1
  4. Matias

    Matias Active Member

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    It is strange, that there’s so much variation with Model 3 results
    Tesla Model 3 Falls Short of a CR Recommendation

    ”In our testing of the Model 3, the first stop we recorded was significantly shorter (around 130 feet, similar to Tesla’s findings), but that distance was not repeated, even after we let the brakes cool overnight.”
     
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  5. N5329K

    N5329K Active Member

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    Comparing stopping distances recorded by any one tester with those from another tester will always show differences. Kind of like running a compression check. Two testers on the same engine will show different results.
    What counts is consistency of method. If CR always does it the same way and found an issue, chances are pretty good there's a real live issue someplace. But putting their numbers against Tesla's proves almost nothing, except that the tests were probably different.
    Robin
     
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  6. SoCalDude

    SoCalDude Member

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    Interesting that the car can stop adequately the first time, but future attempts even on a second test car still had the much longer stopping distance requirements. I am curious if the Anti-lock/traction control capabilities are too relaxed preventing the car from stopping in shorter distances or if it is related to poor brake pad quality (brakes glazing over), smaller than required rotor size or weak braking system and calipers??? I am also curious if the Performance M3 will have larger rotors and braking system???
     
  7. Lloyd

    Lloyd Well-Known Member

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    #7 Lloyd, May 21, 2018
    Last edited: May 21, 2018
    • Informative x 3
  8. gene

    gene Supporting Member

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    We have two Model 3's. Braking has been fine. There has been a few times I had to break hard on the fwy in traffic. It still felt fine. The regen is very strong, much more so than my S was. CR does not say if they tested with regen on high r low.
     
    • Informative x 2
    • Helpful x 1
  9. danbucks

    danbucks Member

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    I refuse to buy this car because its stopping distance is too close to a standard pickup!... said no car buyer EVER.
     
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  10. mongo

    mongo Well-Known Member

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    CR says their standard cool down is about one mile.
    The 3 has aero covers based on the site pic...
     
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  11. Sharkbait

    Sharkbait Member

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    I for one have never considered Consumer Reports an authority on anything except baby diapers and their contents.
     
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  12. Peter Thomas

    Peter Thomas Member

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    With such a fast car, it seems braking should be the most important since the electric drive can accelerate so fast. I would say that braking is more important then acceleration to me since again this is a safety issue and many people give this the highest priority. My suggestion is to check what brake pad your using and see if a different brake pad could improve the situation. Many brake pads are designed for long wear, and, just like tires designed for long wear, they lack in adhesion because the materials are harder and less gripping.

    This may be why your production has not scaled quickly. Scaling production up slowly is allowing Tesla to address some important issues before production is scaled up exponentially.

    Just my 2 cents.
     
  13. KidDoc

    KidDoc Supporting Member

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    This needs to be looked into. There is no reason a car that small should have that poor a breaking distance. From CR's own reporting here is the quote on a Model S P85 which is a MUCH larger and heavier vehicle.

    Braking
    No track testing is done before the vehicle hits 2,000 miles, and we perform a brake seating procedure the day before we take measurements. The test procedure is done on special areas of our test track that are monitored for consistent friction and involves over a dozen stops, with cool-down laps in between to ensure accurate results. We begin measurement as soon as the driver hits the pedal, and the distances are adjusted for temperature. The P85D stopping distances were very short, like a high-performance sports car at 118 feet in the dry and 129 feet in the wet with the optional 21-inch wheel and tire package.
     
    • Informative x 4
  14. Peter Thomas

    Peter Thomas Member

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    I agree that this may be an issue. I strongly suggest that Tesla carefully look into this and initially try looking at the brake pads which could be an easy fix. People usually don't notice bad breaking until it is too late. And now that consumer reports has identified this as a potential issue, take it as a blessing that this was identified early and if it is clearly a problem and addressed now it will definitely save lives.
    Evan
     
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  15. Yedsla

    Yedsla Member

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    Maybe they tried the worst case scenario, with a fully charged battery and no regen.
     
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  16. Daniel in SD

    Daniel in SD Well-Known Member

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    Regen doesn't help braking distance. Every modern car has brakes powerful enough to lock the wheels at speeds way more than 60mph. Regen is limited to .15G acceleration right? Stopping from 60mph in ~130 feet is ~1G of acceleration.
     
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  17. mongo

    mongo Well-Known Member

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    Regen would help with brake fade by offloading some (albeit a small amount, 1/7 in your example) of the braking force.
     
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  18. chao

    chao Member

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    the braking distance is not the main reason i will not recommend, that face that the car itself have many issue that people need to take it into servers for fix or replacement is a daily issue i will not recommend M3.
     
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  19. vinnie97

    vinnie97 #WalkAway

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    Can we start over with this thread without disparaging CR and other organizations so as to avoid a politics argument to nowhere?

    EDIT: I see I'm too late (baby diapers), carry on. I'll see my way out of here, too.
     
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  20. Daniel in SD

    Daniel in SD Well-Known Member

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    I hope Tesla isn't designing cars with that little margin on the brake system! haha
    What if I need to panic brake from a speed higher than 60mph?
     
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