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Is 4.4 seconds vs 5.6 seconds alone worth $10k?

Discussion in 'Model S: Driving Dynamics' started by Jrhodesmd, Mar 29, 2012.

  1. strider

    strider Active Member

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    Yep, that's part of the beauty of an EV. You don't a larger or more complex engine (ie less efficient) to get the added performance so if you drive sedately there is no penalty besides cost.
     
  2. strider

    strider Active Member

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    My take is they would be going after the 911 market - less hard-edged than the Roadster or a Z3. Back seat so you can haul a bit of stuff, easier to get in and out of, more comfortable in general. And Porsche sells a ton of them so the market is there.
     
  3. Teslawisher

    Teslawisher Member

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    Being the total (wheel and tire) diameter for the 19" and 21" is going to be pretty close, the contact patch should be the same (front to back). Only difference would be if the 21" wheels/tires are wider (giving more contact area and better acceleration grip). But, then, of course, tire specs are typically geared more towards performace (softer compounds and such) for higher diameter wheels. So, with all that, I'd say you'll technically get better acceleration with the 21" wheels with more performance spec'd tires, but whether you'll really notice it is to be seen. Finally, acceleration specs is also alot about the driver, so that can be a factor too, unless traction control is involved where all you have to do is punch it. :)
     
  4. onlinespending

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    Right. A 2-door coupe makes far more sense. Current Roadster owners can revel in the fact that they have one of a kind. I don't think Tesla will make another pure roadster EV for quite some time, if ever.
     
  5. AnOutsider

    AnOutsider S532 # XS27

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    Plus, it would be a great halo car (like The R8). Personally, if I own another performance (sports) car, I'd rather have a refreshed roadster than anything ICE.
     
  6. richkae

    richkae VIN587

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    I am confident any performance difference between the 19 and 21s will not be noticeable at the tenth second scale if it even exists in the hundredths of a second.
     
  7. richkae

    richkae VIN587

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    There is no measurable difference in acceleration in a Roadster with "sport" tires vs normal ( which are also performance - just less extreme ) tires.
    The standard tires have more than enough grip for straight line acceleration. The standard tires will likely be sufficient in the Model S as well.
    Go to a racetrack and do more than accelerate hard in a straight line and you will feel the improvement of sport tires.
     
  8. Robert.Boston

    Robert.Boston Model S VIN P01536

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    I have a clear recollection, although no proof, that the 21" rims are markedly wider than the 19". FWIW.
     
  9. ckessel

    ckessel Active Member

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    They can't go too much wider or they'll stick out from the wheel wells and cause drag and/or would scrape the wells on tight turns.
     
  10. drbradfo

    drbradfo Member

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    both tires (21 & 19) have the same width '245'.
     
  11. Robert.Boston

    Robert.Boston Model S VIN P01536

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    I stand corrected.
     
  12. jerry33

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

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    Larger wheels usually mean a heavier assembly--unless the materials are very different. Are the 19" wheels more than 2.8 lbs lighter? They might be if the measuring rim width is chosen. Note that Michelin's TRX tires of a few years ago were designed to solve the problem of getting the largest brake clearance and the lightest assembly. this was done by reducing the rim flange height and reducing the depth of the well. This allowed them to get the brake clearance of a 16" wheel with a 15" rim diameter. Of course, they weren't compatible with anything else and Michelin's marketing was less than stellar so they aren't around any more.

    Here are some numbers from Yokohama:
    19" = 27.6 lbs Tread width 8.7" Measuring rim 8.0"
    21" = 24.8 lbs Tread width 8.9" Measuring rim 8.5"

    I would use the 8.5 inch rim width for the 19" and 9.0" for the 21" tires to get the rim width closer to the tread width.

    The increased acceleration from the 21" will come from the stickier tread compound and perhaps a different belt construction. If both were the same, it looks like a wash as far as acceleration goes. 0.2" will not make a significant difference in contact patch length.
     
  13. William13

    William13 Active Member

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    By the way, I do not see 245/35 R21 at Tire Rack in anything other than summer performance...
     
  14. drbradfo

    drbradfo Member

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    but the 19" have plenty of options, summer performance, summer touring, all-season, winter, etc... many price points, many brands.
     
  15. goyogi

    goyogi Member

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    No, you were right. At the Tesla store using my fingers the 21" rims were about 8" wide and the 19" rims were about 7.5" wide. The "245" is the section width of the tires. Tread width may or may not be different. Rim width can affect the width of the tire.

    If I remember I'll take my tape measure tomorrow since I'm going to hang out with a friend at Santana Row.
     
  16. drbradfo

    drbradfo Member

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    try to get the bolt pattern, rim width, offset, etc of the wheels...
     
  17. William13

    William13 Active Member

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    I believe the bolt pattern isn't enough. Size of bolts and flat or curved also. Previously I had read 5 bolts 112 mm. Don't know accuracy of that.
     
  18. goyogi

    goyogi Member

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    Here's the 19" wheel. 9" wide.
    wheel19.jpg

    Here's the 21" wheel. 9.5" wide
    wheel21.jpg
     
  19. jerry33

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

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    Rim width is measured from inside to inside, not from the outside edges, so the actual rim widths are 8.5 and 9.0.
     
  20. dadaleus

    dadaleus 4GETOIL P85#S70,FdrX,S85D

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    Goyogi, thank you so much for doing that. Now I know I'm going with the 21s.
     

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