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Rear tires for the P85+ with 21x9 rears -- Michelin, Dunlop or Continental?

Discussion in 'Model S: Driving Dynamics' started by bradhs, Feb 10, 2014.

  1. bradhs

    bradhs Member

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    TESLA MODEL S P85+ with the P85+ rims: Front 8.5J x 21 Rear 9.0J x 21 Offset 40mm


    We all know that the best tire out there is the Michelin SuperSport. Problem is they do not make the rear tire for the P85+ yet. The rear tire is a 265/35R21.

    While the PS2 is a great tire it is terrible in the rain and doesn't use some of the newer materials for longevity. It also costs unjustifiably (in the year 2014) more than the SuperSport.

    Until the SuperSport is available I'm going to try and find something else.


    Do you think I can get away with 275 35R21 on the rear of a P85+? If so, I may try the Dunlop SP Sport Maxx GT.


    Dunlop makes a SP Sport Maxx GT with 10/32nd tread depth and almost identical revs per mile, slightly taller 275 x 35% = 3.5mm which is about 1/8" taller of a tire. Load range is XL, fits on a 9-11" rim, section width is almost less than half an inch wider. Revs per mile difference is only 3!! Perfect as to not mess with speedometer.


    Unknown: weight difference and rolling resistance comparison.


    EDIT: Weight: PS2 = 25.4LBS, Dunlop 275 according to TireRack: 31LBS... Not sure how credible the weight is but assuming this tire is slightly wider I could see it weighing an extra few pounds.


    No data on rolling resistance, has anyone researched that?


    See chart.




    2014-01-31_17-48-49.jpg
     
  2. zwede

    zwede 2013 P85+

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  3. bradhs

    bradhs Member

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  4. Lloyd

    Lloyd Active Member

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    I've had sport contacts on my wife's mercedes. They're ok for that car, but IMO the sidewalls are a little soft for the Model S. Good wear though, I have averaged 37K miles per set.
     
  5. zwede

    zwede 2013 P85+

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    The Conti 5P looks interesting. Weighs 26 lbs. Load rating is 101 (same as the Michelin PSII). $416/ea. The Conti is also available in a 245/35/21 so you can do a matching front/rear.

    - - - Updated - - -

    Ok, but what size was it? It's hard to imagine a too soft sidewall in a 35 series tire...
     
  6. Lloyd

    Lloyd Active Member

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    That tire size is 275-55-19
     
  7. simplesolar

    simplesolar Member

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    275 might be fine for 9.5" rim. I am running 285 on 10" rim and it works great.
     
  8. bradhs

    bradhs Member

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    A friend just bought a 2014 BMW 650i GT that came with SP Sport MAXX GT 275/30R20 tires. The rim is 9J x 20”. The Telsa P85+ rear is a 9J x 21”, so 275 tires should be just fine on the rear. I also confirmed with a tire shop and they didn’t think there would be a problem.

    I found a cool tire comparison tool and there is barely a difference, here's the link: http://tire-size-conversion.com/tire-size-calculator/



    Now, need to make a decision between the Continental ContiSportContact 5P or the Dunlop SP Sport MAXX GT.

    Which one should I try?



    http://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=ContiSportContact+5P&partnum=735YR1SPC5XL&vehicleSearch=false&fromCompare1=yes


    http://www.tirerack.com/tires/tires.jsp?tireMake=Dunlop&tireModel=SP+Sport+Maxx+GT&partnum=735YR1SMGTXL&vehicleSearch=false&fromCompare1=yes


    Some of you might ask why would you go from a 265 to a 275. I want a wider-looking tire, range is not as important for me as there are Superchargers everywhere.

     
  9. Mayhemm

    Mayhemm Model S P85+ "Lola"

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    The PSS is now available in 245/35R21 at TireRack (special request, not yet listed on website), which will reportedly also fit the wider rear wheels if you don't mind squaring up the config on your P85+.

    I will be going that route if I need new tires before the PSS is out in 265.
     
  10. brianman

    brianman Burrito Founder

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    Updated information: they are currently listed.

    Tesla, 2012, Model S, 21" (non-plus)
    http://www.tirerack.com/tires/TireSearchResults.jsp?tireIndex=1&autoMake=Tesla&autoYear=2012&autoModel=Model+S&autoModClar=&width=245%2F&ratio=35&diameter=21&sortCode=61030&skipOver=true&minSpeedRating=V&minLoadRating=S&tab=All

    Michelin Pilot Super Sport 245/35ZR21 (linked from ^)
    http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Super+Sport&partnum=435YR1PSSXL&vehicleSearch=true&fromCompare1=yes&autoMake=Tesla&autoYear=2012&autoModel=Model S&autoModClar=
     
  11. bradhs

    bradhs Member

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    I thought about doing that but that would mean 40mm x 2 = 80mm (3 1/8") less width in the rear.

    Also, you're going to get 14mm less diameter.

     
  12. bradhs

    bradhs Member

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    FYI I ordered the Continental ContiSportContact 5P in 275 35R21. My final decision came down to weight. The ContiSportContact 5P weighed less than the SP Sport MAXX GT by 4.7 LB each tire which would have added almost 10 LB of unsprung weight.

    In contrast, the current PS2 (265 35R21) weigh 26 LB. The slight bump in weight is understandable due to the increase in width and height.

    265 35R21
    PS2 = 26 LB

    275 35R21
    ContiSportContact 5P = 27 LB
    SP Sport MAXX GT = 31.7 LB


     
  13. zwede

    zwede 2013 P85+

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    How come you decided on the 275/35-21 (as the Conti is available in 265/35-21)?
     
  14. bradhs

    bradhs Member

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    #14 bradhs, Feb 11, 2014
    Last edited: Feb 11, 2014
    I wanted to go a little wider in the rear.

    The difference between 265 and 275 is:

    10mm (.3937") width x 2 tires = 20 mm (.7874") more rubber on the ground.

    3.5mm (.1378") taller ... Air suspension should automatically adjust for this.


     
  15. zwede

    zwede 2013 P85+

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    Fair enough. You can never have tires that are too wide. :)

    Keep us updated on how you like them. I'm sure I'll be in the market for new tires before too long.
     
  16. simplesolar

    simplesolar Member

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    I think the 275 is also nicer for rim protection as the tires spill over the rim slightly. The additional height will also fill in the wheel gap quite nicely. The unsprung weight does not really have any effects on the way this car handles or accelerates. I switched to 20" which are 10-15lbs lighter on each wheel and haven't notice any big difference. In fact my kWh usage went up a little bit. I think others have documented this as well.
     
  17. bradhs

    bradhs Member

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    Interesting, let's see how these Continential's do. If by the time I need new tires again the SuperSport's are not yet available I'll try the Dunlop's next.

     
  18. mnx

    mnx 2013 P85

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    You won't have any more rubber on the ground, you'll just have a wider/shorter contact patch. :)
     
  19. jerry33

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

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    ^^^ This. Contact patch area is determined almost entirely by the air pressure and load.
     
  20. bradhs

    bradhs Member

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    #20 bradhs, Feb 12, 2014
    Last edited: Feb 13, 2014
    I will get the 275 35R21 Continental ContiSportContact 5P next week and should be able to provide some initial feedback soon.
     
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