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Hubcaps, do they have a role in aerodynamics

Discussion in 'Gen 3 Prius Main Forum' started by Greg C, Jul 23, 2014.

  1. Greg C

    Greg C Junior Member

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    The other day is was out late. When I returned to the car to drive home, it had been vandalised. All wipers pulled up, a hubcap stolen and a sanitary pad (clean) stuck to the windscreen. It took me ages to remove the glue on the windscreen and have taken the other 3 hubcaps off while I wait to get a replacement. Underneath the hubcap of course there is a gloss black coloured mag wheel, that are very in at present. I guess the hubcap must play some role as otherwise why would Toyota waste money on them. The wheel by itself looks OK, just needs a Toyota badge in the middle.

    I am getting a bit tired of the 'bad boy' image I generate and have ordered a new hubcap $A89.20 to quieten the look down though.
     
  2. jdcollins5

    jdcollins5 Senior Member

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    Sorry about your vandalism.

    I am sure there were enough aerodynamic reasons for Toyota to have supplied the hubcaps. Many on here have removed the hubcaps, including me, and have seen only negligible impact to mpg. The improved looks outweighed any loss of mpg.
     
  3. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    +1.

    The hubcaps probably clean up the car aerodynamically for about 1-MPG (at most) worth of difference.
    Without looking.....what are your tire pressures right now and where do you keep them normally???

    If your answer doesn't begin with a "4", then I would buy the missing cap from eBay and take the other three caps off and keep them in a box for when you sell the car or get tired of the unmarked police car look. You won't notice or miss the 1-MPG.

    Me?
    I'm not all that wild about the "somebody jacked your rims!" blackened wheel look, but I'm old fart now and I've never been much of a follower.
    You may want to consider going to Lowe's or HD and going into the electrical department and getting 4 electrical box 'knockout plugs" in 1-1/2" size (IIRC!)
    They'll come in a little bag and look something like this:
    upload_2014-7-23_9-11-9.jpeg [​IMG]

    They will be less than a buck apiece and you can leave them shiny or paint them black to cover the center of the rim.
    You may have to bend the little tabs out a little for a proper fit.

    Or?
    You can go to eBay and pay $20 for center caps that have the "Toyota" crossed butt-hole emblem.



    GOOD LUCK!
     
    elementnomore likes this.
  4. DoubleDAZ

    DoubleDAZ Senior Member

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    I'm still on the fence about air pressure and removing the covers to expose the black wheels.

    I liked the "old school" 5-spoke black mag wheels we had on our Red 1970 GTO and Green & Gold 1999 Montana, but I'm not sure how I'll like them on our Blizzard Pearl Prius. I've looked at other smaller vehicles with black tires/wheels and I'm not sure I like the look. Our 1988 Grand Prix has white allow wheels, so I'm actually thinking about the white dip. So far though no one who has dipped them white has commented about how easy/hard they are to keep clean even though the question has been asked. I don't know anything about dip either, so I don't know how hard it is to clean regardless of color. I did see the photo with the white-dipped wheels where it definitely made the black tires stick out more, so that's also a concern. I may just wait until I need to replace the tires and then decide on some after market wheels or even trade up for the latest Prius Five (or whatever they offer then) with the 17" wheels.

    When it comes to tire pressure, I'm not sure it's the right thing to do considering 70-75% of our driving is during cross-country road trips at 70+ mph. We're retired, so we have no daily commute. We are taking a trip the end of next month and I'm thinking the terrain between Kalispell MT and Green Bay Wi will be similar to that between Green Bay and Phoenix. So, I'm think of leaving everything stock between here and Green Bay and then changing the tire pressure and removing the covers for the return trip. That should at least give me an idea of how the ride and mpg are affected.
     
  5. Jon Hagen

    Jon Hagen Active Member

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    Good posts on this subject. I also removed my wheel ornaments as Toyota calls them. Mine is an early 2010 with the aluminum color wheels. I actually have a practical reason for removing the hubcaps, besides liking the appearance of the wheels better than the hubcaps.
    I live where I must drive 2 miles of gravel road, and had problems with mud / sand buildup between the wheel ornaments and wheels. The imbalance this caused, flat spotted and ruined one rear tire. The actual wheels with the split "tuning fork" spokes also allow access for washing mud from the back side of the wheel rims with a garden hose, while the wide wheel ornament spokes block access to remove the balance destroying mud. My "wheel ornaments" are hanging on the garage wall and will remain there until I sell the car. I will have to try the electrical box plugs to "cap" the hole in the wheels.


    A comment on the tire pressure issue. I run my tires right at the recommended 44psi max cold setting printed on the tire sidewall. The tire maker(Goodyear Assurance fuel max) has already considered hot weather high speed driving pressure rise into the recommended max pressure, so the pressure is within safe limits and will not cause tire safety problems. MPG's are good and tire tread depth remain even across the tire face with 25,000 miles on them, so I am good to go at 44psi.
     
    #5 Jon Hagen, Jul 23, 2014
    Last edited: Jul 23, 2014
  6. Grren4ever

    Grren4ever Active Member

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    Hi Greg C.

    Really sorry to hear about that vandalism. In my college years, I have a old civic that I totally "riced" out. It had the all the front corner lens and rear brake lens tinted dark, green fog lights, a 4 inch muffler tip and some dumb stickers. One day when I got back to my parked car, I found that my emblems got stolen, wipers lifted and fog lights messed up.

    Hopefully I am a lot smarter 15 years later (now). I try to keep the mods low key and clean looking. Absolutely no stickers or big spoilers. And I will get a two way alarm probably at the end of this year. So far no one has tampered with my Prius since one year of ownership (knock on wood).

    Good luck. I actually think the wheels on your car look better without any hubcaps or wheel covers. At least that paint wasn't damaged I presume? One of my highschool friends had his car vandalized back in the 1990's They vandals broke off his antenna and used the metal end to scratch up his entire car!
     
  7. DoubleDAZ

    DoubleDAZ Senior Member

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    Good point, I hadn't thought of that. I'm not anal about mpg, more curious how it does completely stock before I change anything. I don't like wheel covers, so maybe I'm being too anal about staying stock and I should actually consider removing the covers for the trip to help keep the wheels cleaner in case of weather, etc. I just thought the covers would help maximize mpg on the 6,500 mile trip.
     
  8. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I think Toyota's rubbing salt in the wound: first putting plastic wheel covers on the 15" alloys, then switching from silver to black paint.

    Maybe it'll take dealership feedback: new vehicle customers swapping to aftermarket rims right off the bat.
     
  9. Dave14Prius

    Dave14Prius Member

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    Air them up for entire trip, then try your wheel covers off and report back. I think almost everyone knows air up to Max on sidewall is very safe these days with modern tires and gives the best MPG.
     
  10. The Electric Me

    The Electric Me Go Speed Go!

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    You know, Vandalism is cowardly.
    And it sucks.

    But what is interesting here, is you not only have direct vandalism, but the perpetrators had the forethought to bring glue and a sanitary pad to the scene.

    As far as recovery? Well I really dislike the Prius Hubcaps. I think they are ugly. But I have a light colored Prius...Seaglass Pearl, and the black uncovered wheels just don't look good with it.

    So I live with the OEM hubcaps. Someday, I might invest into new wheels or just new better looking hubcaps. I've tried to let the OEM hub caps grow on me, but I'm never going to really like them.

    Hopefully? This was a random and senseless act. And not likely to be repeated.

    But I might be more focused on a alarm upgrade than a hubcap replacement.
     
  11. DoubleDAZ

    DoubleDAZ Senior Member

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    Thanks for commenting Dave. From what I've read here, you seem to offer advice without going into fan-boy mode if someone asks questions or simply doesn't heed the advice. I checked and found them all at 32 when they should be 35/33, max is 44. Since I have a trusted friend who runs 38/36 and got 36,000 on his Goodyear Assurances, I'm going to try upping them to 40/38 to start and run with the covers off for awhile. It seems more prudent to try things before the trip and then I can still run the mpg tests on the trip if I decide it might be worth it. I'd really like to find some center caps with spinners I could dip white. Not sure how they'd look, but they'd be different. :)
     
  12. hybridbear

    hybridbear Member

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    Sorry to hear about vandalism
     
  13. Tideland Prius

    Tideland Prius Moderator of the North
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    I don't know about the newer design but at least with the 2010-2011 design, the wheelcover was meant to smooth the airflow around the side of the car as it passes the wheels. (At least based on the translation from Chief Engineer Akihiko Otsuka).

    In addition, they help a little bit with weight reduction. Toyota can use less metal alloy for the wheels and use the plastic covers to finish the design.
     
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  14. elementnomore

    elementnomore Member

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    Sorry to hear about your car. I'm happy to part with my hub caps. Feel free to pm me.
     
  15. Kennyboy

    Kennyboy New Member

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    Hello Elementnomore,
    Do you still have your hubcaps? I'm looking for two of them p/n 42603-47060. If you still have them how much do you want for two of them?
    Thanks
    Kennyboy
     
  16. CR94

    CR94 Senior Member

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    Did Chief Engineer Otsuka say specifically how much effect they have on the drag coefficient, EPA mileage number, or any other objective quantity? The silly things add 3½ pounds of (unsprung) weight. We who live in hilly areas might like to have enough data to estimate whether that weight is costing more in fuel (and other drawbacks of unneeded weight) than they save through slightly reduced aero drag.

    So far, I compromise by putting the covers on for long Interstate trips, but leaving them off for local driving, in which speeds are generally lower and stops, starts, and hills are more numerous.
     
  17. xliderider

    xliderider Senior Member

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    Our fuelly mpg is without hubcaps, they came off within the first week. Take them off, the mpg effect is negligible.
     
  18. DoubleDAZ

    DoubleDAZ Senior Member

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    Neither my 18-yr old grandson nor my wife likes the black alloy wheels under the covers on our 2014 BP and I wasn't partial to them, so I put the covers back on. :)
     
  19. kenichols29

    kenichols29 Active Member

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    The only time Ive ever noticed getting better MPG with the hubcaps is when I drive with a cross wind. Other than that they dont seem to affect my mpg much.
     
  20. Tideland Prius

    Tideland Prius Moderator of the North
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    No, but he did mention a 1-2mpg loss going to the 17" alloys (presumably because of unsprung weight as the main factor). The 15" alloys are really light.

    All he did was to explain that the covers were meant to the smooth the air flow between the front bumper and the front doors. (I presume the same for the rear but we were at the front of the car when he explained it. He also took the opportunity to explain the slats at the back of the front wheel well meant to reduce back pressure of the air that's swirling within the wheel well. A number of cars have this feature anyway so it's nothing new or special).