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Weight of Wheel/Rims vs. MPG

Discussion in 'Prius c Fuel Economy' started by 88Keys444, Aug 31, 2019.

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  1. 88Keys444

    88Keys444 Junior Member

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    Hey guys,

    I still have the stock OEM wheels on my Prius C, which I believe are about 16.5 lbs. I found some wheels weighing at 11.1 lbs, so I'd be getting about 5.5 lbs removed in unsprung weight.

    Has anyone experienced any change in MPG after getting lighter wheels? I'd love to increase MPG and I love the look of them, as well.

    Here's what they look like:

    81EuYRuh0fL._SL1500_.jpg
     
    #1 88Keys444, Aug 31, 2019
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  2. PriusCamper

    PriusCamper Senior Member

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    Yes it will make a big difference, one of the few things you can do to improve MPG... The reason this is not done often is because getting 4-5 pounds of weight out of each wheel means you're going to spend several thousand per wheel for forged alloy racing wheels, which makes for a bad day if you hit a curb, especially if you're a frugal Prius driver. :)

    But maybe you're the lucky winner who got a great deal that makes all the rest of us jealous... :)

    Or maybe your stock wheels were those lame super heavy cheap steel wheels they were putting on early model Prius C and you're just upgrading to normal non-cheap wheels and it will make a difference, but not as much?

    My dream has always been able to win the lottery and blow $10K on some under 10 pound pound racing wheels... The few people who have done this back when Gen2 Prius were first coming said it will made a noticeable difference in both acceleration and MPG. Anyone who's worked on bicycles will tell you... The lighter the wheel, the better you'll be in a race.
     
    #2 PriusCamper, Aug 31, 2019
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  3. PriusCamper

    PriusCamper Senior Member

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    PS: If the lighter wheels don't match up to exact spec for max mpg and you aren't using LRR tires, the MPG won't change much and in some cases could get much worse.
     
    #3 PriusCamper, Aug 31, 2019
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  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Funny thing, steel rims of comparative size are pretty much neck-and-neck for weight.
     
    #4 Mendel Leisk, Aug 31, 2019
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  5. bisco

    bisco cookie crumbler

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    interestingly, the difference in mpg of the hycao le vs the two higher end packages is supposedly in the wheel size and weight.
    affects drive quality too, i suppose
     
    #5 bisco, Aug 31, 2019
  6. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Our 3rd gen's 17" rims are around 24 pounds apiece, oink...
     
    #6 Mendel Leisk, Aug 31, 2019
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  7. 88Keys444

    88Keys444 Junior Member

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    Second one:) I have a 2013. The ones I found are on Amazon for 105 a tire. Nothing crazy at all. I'm thinking a 20lbs reduction in unsprung weight would be HUGE for mpg.

    I have LRRs, Continental TrueContacts. It seems like everything's panning out:D
     
    #7 88Keys444, Sep 1, 2019
  8. 88Keys444

    88Keys444 Junior Member

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    WEW that's heavy
     
    #8 88Keys444, Sep 1, 2019
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  9. 88Keys444

    88Keys444 Junior Member

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    Yeah I think it's worth shot to try it out. I replaced my stock tires with some Continentals, and combined they're 8lbs lighter than the OEM. I can say I have not seen a drop in MPG, which is shocking considering the old ones were bald with no traction. But after breaking in the new tires a bit, I've been noticing 1-2 MPG gains each drive without changing any driving habits. Pretty solid:)
     
    #9 88Keys444, Sep 1, 2019
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  10. PriusCamper

    PriusCamper Senior Member

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    I'd love to see a link to super lightweight wheels that are affordable... I'm sure many others on here would too... Please share when you get a chance.
     
    #10 PriusCamper, Sep 1, 2019
  11. 88Keys444

    88Keys444 Junior Member

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    Sorry! I thought I already did.

    Here it is:

    https://www.discounttire.com/buy-wheels/konig-helium
     
    #11 88Keys444, Sep 1, 2019
  12. 88Keys444

    88Keys444 Junior Member

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    So I have decided to do my own test on this since I'm tired of searching all over the internet:sleep:

    The question will be: Does reducing wheel weight increase fuel efficiency?

    After researching the true weight of my OEM 2013 Prius C wheel, I am SHOCKED at how much it weighs: 19LBS!!!!! Here is the link to it:

    2012-2019 15x5 Toyota Prius C Steel Wheel Rim- Road Ready - Road Ready Wheels - OEM Replica Wheel Supplier

    No wonder my acceleration is god awful. A buddy of mine has a 2013 Prius C as well, but I have the One and he has the Three, so he got lighter tires. Everytime I drive it, I notice his acceleration is EXTREMELY better. However, that is not what we're testing.

    I could ask him what his MPG is, but that doesn't prove anything since there is no control. His driving style is going to be different than mine, as well as distance, routes taken, amount of miles, etc. Way too many factors to consider.

    Current Tire/Wheel Setup

    Continental TrueContact Tour -     175/65/15R (OEM Size)

    The current psi is:

    Front - 36 psi
    Rear - 34 psi

    Weight - 15lbs


    Stock OEM Wheels - 15x5

    Weight - 19lbs
    Weight each Tire/Wheel: 34lbs

    Total Weight: 136lbs :(

    Stock hubcaps are also on.



    "Upgraded" Setup

    The tires will be the same

    Weight per tire: 15lbs
    Total: 60lbs
    The psi will also be the same

    Aftermarket Wheels - Konig Helium

    Dimension - 15x6.5
    Weight - 11.1lbs
    Weight Each Tire/Wheel - 26.1lbs
    Total: 104.4lbs

    Difference in weight with Current vs. Upgraded - 31.6lbs


    Hypthesis: With such a huge difference in weight, the aftermarket wheels will improve MPG by a large amount.
    Less unsprung weight = less resistance = better fuel economy?

    Data will be collected for three weeks on each setup. Each drive will be logged.


    Variables to consider:
    The width of the Konig Heliums may affect MPG
    The aerodynamics will change with the Konigs. They do not block as much surface area as the stocks with the hubcaps on.




    I'd love to read what you guys think will happen. Will a reduction of 31.6lbs affect the MPG? Will wind resistance cancel it all out? Let me know!:D
     
    #12 88Keys444, Sep 1, 2019
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  13. PriusCamper

    PriusCamper Senior Member

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    Also experiment with slowly adding 2-3psi in each tire and then back it off once you start to lose traction. ON my Gen2 Prius, which is a heavier vehicle, I get faster handling and way higher mpg with 47psi in front and 45psi in the rears... And my last set of tires I got 70K miles and near perfectly even wear even though the tires were only rated for 60K miles at 35psi.
     
    #13 PriusCamper, Sep 1, 2019
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  14. 88Keys444

    88Keys444 Junior Member

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    Very nice! Any difference in the ride smoothness? I don't mind giving up a little bit of MPG for coziness, but I don't think I've experimented enough with psi
     
    #14 88Keys444, Sep 2, 2019
  15. roadrunner

    roadrunner His (blue) and hers (black).

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    I have weighed the 15" steel wheels (15 lb), and the 15" alloy wheels (15 lbs). Both are w/o the tire.
     
    #15 roadrunner, Sep 2, 2019
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  16. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I did somewhat similar with a 15" steel Corolla rim, except it had a mounted Michelin X-Ice tire. I weighed the whole thing, then deducted the tire weight, as listed on TireRack. Again, worked out to around 15 pounds for the rim.

    (I ignored the balancing weights, which would lower the rim weight more if considered. But peanuts? Also, how much more does compressed air weigh? More peanuts? And valve stem and tpms sensor.)
     
    #16 Mendel Leisk, Sep 2, 2019
  17. 88Keys444

    88Keys444 Junior Member

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    #17 88Keys444, Sep 2, 2019
  18. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yeah I saw that link. Just for giggles: weigh them?
     
    #18 Mendel Leisk, Sep 2, 2019
  19. 88Keys444

    88Keys444 Junior Member

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    Sorry, I forgot I already posted the link. I have weighed them in the past and they are indeed 19lbs
     
    #19 88Keys444, Sep 2, 2019
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  20. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Hang on, you’re replacing 5” wheels with 6.5” wheels. That’s going to make a change too.
     
    #20 Leadfoot J. McCoalroller, Sep 2, 2019
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