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Upgraded to 22's and ate 20% efficiency

Discussion in 'Model S: Driving Dynamics' started by G.Hawkinz, Dec 31, 2013.

  1. G.Hawkinz

    G.Hawkinz New Member

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    For those that have upgraded to a 22" wheel set, have you noticed a difference in efficiency? After my additions, it looks like I've gone from an average energy usage of 320Wh/mi to about 380Wh/mi. If it's not the wheels, then it's the 5.8.4 update that just pushed... Thoughts? (Side note: I'm waiting for wheel and tire weight from the manufacturer as I type this)
     
  2. richkae

    richkae VIN587

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    You haven't provided enough data to compare.
    What did you upgrade to ( wheels and tires ) - and what did you upgrade from ( wheels and tires ).
    How many miles do you have on each? Are you through the break in period of the new tires?
     
  3. G.Hawkinz

    G.Hawkinz New Member

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    I went from the stock 19s to CEC C881s in 22". I had 400 miles on the 19s and about 200 on the 22s now. I would assume I'm still in the "break in" period.
     
  4. jcaspar

    jcaspar Member

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    What size tires on your 22" wheels?
     
  5. Gizmotoy

    Gizmotoy Active Member

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    And just as importantly, what kind of tires (brand/model/style)?
     
  6. joer00

    joer00 Member

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    Can you please post a pic ? I would like to see if the looks are worth the range loss. I need to replace my Hankooks soon and as they are terrible with no grip I am looking what to put on next. Is yours a P ?
     
  7. ghawkinz

    ghawkinz New Member

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    They're Lexani Nine 255/30ZR22
     
  8. G.Hawkinz

    G.Hawkinz New Member

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    2013-12-31 10.56.24.jpg

    - - - Updated - - -

    Side note: I think the issue is simply the big change in weather...
     
  9. richkae

    richkae VIN587

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    When you say stock 19s do you mean the Michelin Primacy tires or the Goodyears? Because the Goodyears are "good" for rolling resistance, but the Michelins are great.

    When I switched from the Continental Sports that came on the signature 21" inch wheels to the Michelin Primacy tires on 19" wheels my wh/mile went down a lot.
    Unfortunately it is not a valid comparison, because I was driving on the 21s in cold fall weather and was on the Michelins in the spring/summer early fall, but the 19" Michelins were about 15% less wh/mile than the 21" Continental Sports. However the wh/mile of the Michelins got significantly worse from september to november when it got colder.

    Losing 20% going from 19" Michelin Primacy tires ( made to be very efficient ) to 22" performance tires that are most likely manufactured with no consideration given to efficiency does not suprise me in the least.
     
  10. tdiggity

    tdiggity Member

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    Try turning your climate control off and doing a test run along a known wh/mi route.
     
  11. ImperialG

    ImperialG Member

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    Oh my GOODNESS that looks amazing.
     
  12. horst98

    horst98 Member

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    Sorry to say this. But moving to broader wheels and not expecting less efficiency is somewhat unrealistic. Tesla tried to reduce wind resistance by optimizing the Cd factor and you are increasing the surface area of the car Cda. Look at a BMW i3 - they come with very thin tires like 155mm. This is more than three inches thinner than the 'normal' 19" 245mm tires of our car.
     
  13. yobigd20

    yobigd20 Well-Known Member

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    thats why I fully expect Gen III to have 15" wheels. smaller car = smaller space for battery pack = smaller battery = need to increase efficiency to maintain 200+ mile ranges.
     
  14. tdiggity

    tdiggity Member

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    I don't think anyone's quantified how much less efficient going bigger is. OP probably didn't expect that much of a difference. IMO, the difference he is seeing seems large, too.
     
  15. jerry33

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

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    That much of a difference is no surprise There are several things that happen:

    1. The wheel is heavier.

    2. The mass of the wheel and tire are further from the centre of rotation.

    3. Tread width is wider (making for more material to bend during each transition from free radius to loaded radius).

    4. The lower profile tire typically has a stickier tread compound.

    5. Up and down movement from road irregularities moves more mass.

    6. The OE tires were chosen partly for good rolling resistance values.

    I've experienced this kind of drop when going to plus one or plus two sizing many times in other cars.
     
  16. G.Hawkinz

    G.Hawkinz New Member

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    Yep, It was the cold weather mixed in with the change in wheel size. I expected to lose around 3-7% tops but the 30-40 degree weather here in Houston compared to mid 70s made up the other difference in efficiency. I'm back to 330s-340s on the same route in the 60-70 Degree weather. Plus I was panicking as a newbie lol :p. Thanks to all for your replies!
     
  17. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    From another thread dealing with a similar topic:

    So we are looking at roughly a 6% penalty in going from standard 19" (Goodyears) to 21" performance tires. Assuming that the 22" are wider we can expect even more than 6% or more than about 9% when compared with the 19" Michelin Primacy tires.

    Larry
     

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