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Model S Wheel and Tire Load Ratings

Discussion in 'Model S: Driving Dynamics' started by AoneOne, Nov 16, 2014.

  1. AoneOne

    AoneOne Member

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    Location:
    Fox Chapel (Pittsburgh), PA
    Not being an expert on suspension design, I'd like some help understanding wheel and tire load ratings for the Model S.

    First, a bit of background:

    In some other posts, I've seen the rear GAWR listed at 3131 lbs (see any experts on tyre load index ?). Tire Rack uses this as their reference value, according to my correspondence with them. For example, the OZ Ultraleggera HLT they recommend for the Model S has a load rating of 1573 pounds, a bit more than half of that GAWR (1566 lbs).

    On my S 85, manufactured in late August, 2013, the door sticker shows 1500 kg (3307 lbs), so half of that is 1654 lbs, 81 more than the Ultraleggera rating.

    I do note that the load rating on the Michelin MXM4 245/45R19 is 98 meaning 750 kg, matching the GAWR.


    Now for my questions:

    In general, I'd like to know: are the required wheel and tire ratings equal to GAWR divided by 2? Is that sufficient to handle the non-gravitational forces (acceleration, braking, and cornering)?

    If the Ultraleggera are only rated at 95% of the half GAWR, does that pose a risk of unexpected failure, especially in an everyday car that is subject to the occasional pothole?

    Finally, are the load ratings for Tesla's own wheels available? Are they stamped into the inside of the wheels?

    Thanks.
     
  2. AoneOne

    AoneOne Member

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    Location:
    Fox Chapel (Pittsburgh), PA
    Bump. Does anyone have any advice regarding wheel load ratings?
     
  3. jerry33

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

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    Gross axle capacity is based on the lowest rated component in the axle assembly as delivered from the factory. The 98 LI of the tires matching the GAWR likely translates to "The tires are the lowest rated component". If you put on wheels with a lower capacity, strictly speaking you should lower the load you carry.

    Pothole damage frequency is reduced by keeping your tires inflated. This is especially true if you go larger than the 19" tires.

    There are some posts where it's said that Tesla won't fix warped rotors under warranty with aftermarket wheels because Tesla believed the wheels weren't heavy enough and caused the rotors to warp. I don't have any first hand experience in this and not all posters received the same statement from Tesla, so I'll leave it at that.

    Most wheels have the load rating stamped on them--but I haven't actually looked at mine.

    As far as the wheels you want to put on, if TireRack has recommended them presumably they will stand behind any problems that the wheels cause.
     

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