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Recommended Tire Pressure

Discussion in 'Model S: Driving Dynamics' started by dsm363, Oct 7, 2012.

  1. dsm363

    dsm363 Roadster + Sig Model S

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    #1 dsm363, Oct 7, 2012
    Last edited: Oct 7, 2012
    I e-mailed Tesla asking about recommend cold tire pressure since it doesn't seem to be in the manual other than to say 'check label on car'. On my car, it says 42psi but the car came at 47psi for all tires. There doesn't appear to be two recommended tires pressures (one comfort and one for efficiency) like on the Roadster.
     
  2. jerry33

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

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    The 42 psi will be the cold tire pressure. You then have to adjust it based on conditions. Sports cars often have two or three pressures because most folks don't know how to calculate the adjustments (or that they even need to) and sports cars are expected to have a variety of driving styles. Sedans generally have one pressure recommendation. A few have two.
     
  3. dsm363

    dsm363 Roadster + Sig Model S

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    #3 dsm363, Oct 7, 2012
    Last edited: Oct 7, 2012
    My car has been sitting for over 24 hours now and it's pretty cold outside. Since all my tires were at 47psi, I lowered them to the recommend 42psi. For more spirited driving, should I bump it back up to 47psi? Looks like the max psi on the tire is 51. Thanks.
     
  4. Jason S

    Jason S Model S Sig Perf (P85)

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    iirc, you have the 21" tires. I think the recommended setting would be the 'spirited driving' setting, since that's what the tires were designed for.

    So go with 42psi
     
  5. pdwitt

    pdwitt Member

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    The tires are overinflated for the van trip to reduce flat spots.
     
  6. jerry33

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

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    1. Steel belted radial tires don't flat-spot (unless perhaps the car is left to sit for months on end, but the week in a transporter isn't going to do it). Flat-spotting is a quality of tires built with nylon casings. The nylon cap ply that some tires have doesn't cause the tire to flat-spot. However, the tires can be damaged by the flanges on the trailer. Higher inflation pressure helps prevent this damage.

    2. Tires that are at or below the maximum pressure listed on the sidewall of the tire (when the tires are cold) are not overinflated. (This is kind of a sore spot with me. I've seen way too many tires ruined by low inflation pressures because the drivers appear to be scared of over-inflating the tires. It's not pressure that ruins tires--it's heat).
     
  7. colinb

    colinb Member

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    Does anyone know if the 42psi cold pressure recommendation applies to the 19" Pirelli Sottozero Winter 240s they put on as part of the winter tire package? I've been having a variety of TPMS warnings pop up since the start.
     
  8. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Tesla has a service bulletin out to reprogram the TPMS "low-pressure threshold" to 36 PSI instead of 38.5 which reduces the low tire pressure warnings on cold days.

    On the transporters they are inflating to 46-50 PSI cold instead of 42. When my car was delivered, we brought them down to 42 PSI. These are 21" wheels.
     
  9. dsm363

    dsm363 Roadster + Sig Model S

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    Is there a chart that shows ambient temperature and what tire pressure should be since recommended cold tire pressure is at a certain temperature?
     
  10. Doug_G

    Doug_G Lead Moderator

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    The cold tire pressure should always be the same, regardless of what that "cold" ambient is. If the tires rise, say, 20 degrees during highway driving, it will rise by approximately the same amount regardless of the ambient temperature. So the "hot" pressure will also go up by roughly the same amount, regardless of the ambient temperature you started at. You should adjust your cold tire pressures seasonally as required to maintain the same "cold" pressure.
     
  11. NJS1207

    NJS1207 Member

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    I was advised by the service center that all 19" tires, including the Pirellis, should be inflated to 45psi. The 21" tires should be inflated to 42psi.
     
  12. jerry33

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

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    +1. In addition, if you are inflating inside with 65F (18C) air, you need to add some more to compensate for shrinkage when the car goes outside.
     
  13. Brian H

    Brian H Banned

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    Yes, clearly they're not going to warm up to proper running pressure on the transport and need to be raised 'artificially'.
     
  14. jerry33

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

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    The main reason for high pressure in shipping is that transports tend to have lots of sidewall-destroying things on them and raising the pressure reduces the chance the tires will be damaged. it also makes the tie-downs more effective because there is less tire deformation.

    There is nothing like getting 100 calls about "defective new tires" when some transport company has damaged the tires on every car they shipped.
     

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