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Aero wheels

Discussion in 'Model S: Driving Dynamics' started by richkae, Oct 3, 2011.

  1. jcstp

    jcstp Active Member

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  2. Lyon

    Lyon 2016 S P100DL, 2016 X P90D

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    Have you noticed any issues with the wheels being out of balance with them on? Otherwise I like the idea of being able to remove/add them as needed.
     
  3. jerry33

    jerry33 (S85-3/2/13 traded in) X LR: F2611##-3/27/20

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    I wouldn't think there would be. Pizza plates are fairly uniform being stamped from a piece of metal that has reasonable thickness tolerances. Also there isn't much weight around the circumference of the pizza plate. The fasteners aren't close to the rim either. I wouldn't expect balance problems at any legal speed.
     
  4. Chgd Up

    Chgd Up Sig 1004

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    No balance issues but as I noted I was very careful to center the covers. If they were off center then they would definitely be an imbalance wobble. This is a real down side to not having the rim lip to mount to like a conventional wheel cover.

    I have more concerns with the cooling as noted the front heat exchangers vent into the wheel wells so in addition to brake cooling the battery/powertrain cooling is vented here.

    I did run a series of three hard 60-0 stops and measure the disk temperature w/o the cover 163F and with the cover 201F so it is definitely affecting the rotor cooling.
     
  5. JRP3

    JRP3 Hyperactive Member

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    How about in normal driving? Three hard stops like that is unusual.
     
  6. jerry33

    jerry33 (S85-3/2/13 traded in) X LR: F2611##-3/27/20

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    That might actually help given that the brakes in the Model S don't get used that much. (Not on track day though.) There are a number of about brakes not getting used enough on the Roadster.
     
  7. Grendal

    Grendal SpaceX Moderator

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    Aero wheels were dropped. Has anyone tried to find alternatives?

    Someone found 19" turbine wheels, anyone trying to get or have found alternative aero wheels?

    Just curious.
     
  8. rick325

    rick325 Member

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    You want to check this thread: 320 mile wheels
     
  9. Grendal

    Grendal SpaceX Moderator

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    Since drag increases due to speed, I'd be curious how much energy you're saving at highway speeds of 75 MPH and 80 MPH. Even with your 6.5% increase you're getting 280 miles out of your pack using the EPA numbers.

    There has to be a sweet spot for cooling your rotors versus increase in aerodynamics. How large of holes can you get away with while maintaining most of the aero gains?
     
  10. jerry33

    jerry33 (S85-3/2/13 traded in) X LR: F2611##-3/27/20

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    With most of the braking being done by the motor, you're more likely to want the higher rotor temperatures so that the brakes work when you really need them. Probably no holes is the optimum for normal driving.
     
  11. Chgd Up

    Chgd Up Sig 1004

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    #411 Chgd Up, Jan 8, 2013
    Last edited: Jan 8, 2013
    I'm not certain that the percentage would change but the energy savings would definitely be higher. Unfortunately I haven't had a chance to run any higher speed trials but what I saw at 60 mph with runs two directions on dry roads and the heat off was 305 wh/mi with the covers 325 without, running Michelin MXM4s at 47psi on the 19" rims.
     
  12. doug

    doug Administrator / Head Moderator

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    Where are you parked that there are what look like 100 liter cryogenic dewars in the background?
     
  13. Chgd Up

    Chgd Up Sig 1004

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    I was parked at the lab and I wasn't looking at what was on the slab, or seeing if the powertrain could be cryogenically cooled to allow for speeds over 135 mph.

    We use the liquid nitrogen dewars to generate extreme temperature environments to test aerospace components.
     
  14. GSP

    GSP Member

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    #414 GSP, Jan 19, 2013
    Last edited: Jan 19, 2013
    Active Aero Wheels on Ford Atlas Concept Truck

    http://media.ford.com/images/10031/AtlasConcept.pdf

    "Active Wheel Shutters Automatic shutters in the wheels are hidden to improve style at rest and low speeds, but automatically close at highway speeds to help improve aerodynamics. Self-charging batteries from wheel motion provide shutter power"

    This would be great for the Model S. Show off the fabulous brake calipers and provoke cooling at low speed or stopped, and also get more highway miles.

    GSP

    image.jpg

    image.jpg
     
  15. JRP3

    JRP3 Hyperactive Member

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    Makes me think there could be a system using centrifugal force instead of electric power. Weighted sections with light springs that are forced closed above say 45 mph.
     
  16. dailydriver

    dailydriver Member

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    That would seem to be a very elegant, simple, and efficient solution.
     
  17. Alpha

    Alpha Member

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    @Chgd Up This is awesome! 6.5% energy reduction with such a simple, cheap solution! Have you done any more extensive testing to see what the actual definitive range increase is? Do you drive around with the pie plates all the time? I wonder why Tesla doesn't make a snap on hubcap similar to something like this themselves (maybe with the addition of a few appropriately placed cooling vents) since they have all that fantastic aluminum stamping equipment...
     
  18. Cattledog

    Cattledog Active Member

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    Especially if you can voice activate by saying "Shields!"
     
  19. Chgd Up

    Chgd Up Sig 1004

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    I've done a few 200+ mile runs and they do give me about 30 miles more range. However I find there's a great temptation to just drive 5% faster.

    I don't love the aesthetic of the pans I tried painting them black but that doesn't work for me either, you need the whole blacked out car then.
    I'm toying with the idea of having some friends make up carbon fiber disks, but I'm loving the shutters.
     
  20. Alpha

    Alpha Member

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    30 miles extra range! Very nice for basically a $60 investment - I assume you find yourself trying to rely on regen. as much as possible and only braking when absolutely necessary. Carbon fiber disks would probably costs a few hundred at least but would obviously be lighter and possibly a lot better looking if designed well... But I don't think the weight difference would be very substantial at all. Completely carbon fiber wheels with an aerodynamic design would probably make a real difference as it would probably shave a good 40-50 pounds off the car as well as reduce drag - but that would be really big bucks...

    I am thinking about getting the 60kWh battery (haven't finalized yet) and there is one particular trip that I make off the beaten path that is close to 200 miles that I am slightly nervous about - having an extra 30 miles of range available would give a bit of extra confidence for trips like that.
     

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