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Why anyone needs a car that does 155 mph or a roof rack good for 140 mph

Discussion in 'Model S: Driving Dynamics' started by Ross1, Feb 6, 2016.

  1. Ross1

    Ross1 Member

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    Actually the car is limited to 155mph
    They Who Know figured this was the sensible speed to limit it at.
    But who actually wants to drive at 155? Maybe those who want to drive fast would drive faster if it wasn't limited to 155. And those who want to drive slower...nearly 100 % of the population..want to drive slower. Maybe a top speed of half that would suit 99%. Or 2 std deviations.

    I rarely go over 125 mph. And only when I am being an idiot.
    I understand Elon said the roof rack on MX is good for, no, guaranteed for 140 mph.
    Why would you drive with a roof rack at 140? I suppose I might have done when I was a bigger idiot than I am now.
    Would you carry kayaks up there? 2x4s? 4x8 ft. plywood? Mother-in-law?


    Perhaps it is just to compete with others in the market, but the same question applies. Why?

    Perhaps it is because they can. (build a car that does 155).
    But since they can possibly get much greater speed from S and X, why limit it so it looks like you can 'only' do 155?

    I think there is one basic area you can legally do those speeds in Australia. (Northern Territory). And Germany. Where else? Antarctica?
    Perhaps the cars are designed to be sold to idiots.

    BTW, in 6 months on the 'other' forum, I never copped a McLary bashing. Idiot, lol. What he missed.
     
  2. kort677

    kort677 Active Member

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    how many people ever drive the car at the highest possible speeds? and if they where going to try doing such speeds I would think that they would remove their racks
     
  3. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    At car shows I do get questions about what the top speed it. It's apparently important to those folks who equate top speed with being better. I don't really get this myself, but I fully get that if the top speed isn't very high, sales will suffer if the car is a high end car.
     
  4. Saghost

    Saghost Active Member

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    Tesla needs a car that can go 155 because they are trying to draw buyers from Mercedes AMG and BMW M cars who will look at that specification carefully, even if they never actually drive that fast. 155 is the limit for most sports cars because of tires - only a very few highly specialized tires can handle the heating above this speed for any length of time.
    Walter
     
  5. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    It's a fair set of questions to ask, but I would suggest the answer lies in the same field where you'll find the answer to "Why would anyone want a car that is strong enough to stack five of them atop one another?".

    If I have a roof rack that's good to 140mph, that means that I needn't worry about it....consider it...even think about it at 80.

    And so on.
     
  6. spottyq

    spottyq Member

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    So you don't have a problem driving 90mph in a 40mph headwind. :)

    (I made the assumption here that the roof rack does not care about ground speed, but rather speed relative to the air rushing around it.)
     
  7. tstafford

    tstafford Member

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    I wonder what my projected range would be under those circumstances - maybe 80 miles, maybe!
     
  8. P85DEE

    P85DEE Active Member

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    Why do we "need" underwear?

    The only reason why you wear socks and underwear is because "you can".
     
  9. McRat

    McRat Active Member

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    #9 McRat, Feb 7, 2016
    Last edited: Feb 7, 2016
    While that used to true, things have changed. Cars that go over 150mph became common starting in the 1990's, even downright cheap.
    It used to be that a ZR designation was the catchall for high speed tires (up to 150), but now there wide selection of tires for today's faster cars.
    W - rated are <168mph, Y - <186, and (Y) past 186. Now that dozens of affordable cars can exceed 186, you should always replace your OEM tires with the same OEM tire if you intend on going over 186, and especially if you are going past 200mph.

    If there are cars that go over 200, then why did they stop the scale at Y? They had already used Z a long time ago. The parentheses thing for Y rating is a catchall. It is what you see on Bugatti Veyron.

    Why so many crazy fast cars today? Since CAFE standards made cars more aerodynamic, and ICE engines get good MPG at low RPM, unless they put an electronic limiter on a car, they go pretty fast up top. You can't go 0-60mph quickly, have tall mileage gearing, and good aero, without the ability to go really fast up top.

    The 155mph is a "magic number" and is where a lot of cars are capped at due to european influence (250 kmh), and so is 186mph (300kmh). Tire numbers are 149, 168, 186mph.
     
  10. Johann Koeber

    Johann Koeber Member

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    Not many people need a car going so fast.

    I would be fine with a user adjustable limit (some mercedes cars have it). It would help me in the rare occasions I get carried away and go much too fast (German Autobahn).
     
  11. Larry93428

    Larry93428 Member

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    Doing yard work and this guy walks by, asked how I like the car. "Love it" I said. He told me he is also an owner. "Yeah, I know. I see it go by."
    "No, the car is in Wales." He winters here with his daughter.
    But to the point, he said there is no speed limit in Wales, outside of town. He can do 150 there.
    ~Larry
     
  12. jpet

    jpet Jan P.

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    Because it is better to have additional protection when you drive 155 mph. :cool:
     
  13. Ross1

    Ross1 Member

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    (Original OP)
    Lots of good answers, but no answer yet?
    Is there anyone here who has driven MS or MX at 155 (250 kph) or the MX with a roof rack at 140?
     
  14. jpet

    jpet Jan P.

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    I have. I am located in Europe. I have taken my P85D to the track and I have been at the German Autobahn several times where it is legally possible to max the car out at certain locations. The max speed of my P85D is 249 kph. Above 235 kph the rear motor is put in torque sleep because it can not go beyond 16000 rpm. The front motor can run up to 18000 rpm but at 249 kph / 250 kph it is over. I would even say that above 200 kph the car is accelerating so slow that one has to be aware that other cars with more than 350 to 400 hp can overtake you quite easily.

    Having 21" wheels and the sport suspension my car is quite stable at high speeds. I don't have a problem pushing it to the max providing traffic permits.
     
  15. McRat

    McRat Active Member

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    #15 McRat, Feb 7, 2016
    Last edited: Feb 7, 2016
    I can tell you a production GMC truck will actually peel off the trim at speeds over 175mph. We had to tear them all off to hit 200 mph. About 936rwhp was necessary.

    If you could alter the gearing on a Model S, it would exceed 200mph, but very briefly. The power required would empty the battery in just a few minutes. Depending on the cooling system, it could be very brief.
     
  16. Ross1

    Ross1 Member

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    200 mph production truck?
    Even in Aus, well ,
    I should rephrase the OP, Why would any sane person etc
     
  17. purplewalt

    purplewalt Active Member

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    Advertisement during the Super Bowl for Audi A8, claims top speed of 205 mph.
    I have no idea where you could even used such performance on the street (legally), or why you would need to.

    oh well...
     
  18. GoTslaGo

    GoTslaGo Learning Member

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    I apologize in advance for my ignorance, but I thought the MX couldn't have a roof rack. Do you mean the MS with a roof rack at 140?
     
  19. Ross1

    Ross1 Member

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    I am pretty sure it was MX Elon was talking about. I think you leave one wing door out of action, does that sound right?
     
  20. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    He was indeed talking about the Model X; with these vacuum mounts (not suction cups....) a rack (Whisper, I'm sure) are supposed to be good to 140mph. Me, I'd not go a whisker over 135 with 'em.

    Picture here:

    1002-1-4-80x80.jpg
     

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