1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Allowable tire sizes

Discussion in 'Gen 2 Prius Main Forum' started by derohanes, May 22, 2011.

  1. derohanes

    derohanes New Member

    Joined:
    Mar 3, 2007
    4
    0
    0
    I have a 2006 Prius with the standard rims. A few years ago I read an article about changing tire sizes. I can seem to find that article, which cautions against going over a certain size due to excessive speedometer error and tire rubbing. I wasn't in the market for tires then, but I am now and can't seem to locate that thread. I found others, but they don't address the rubbing issue.

    Can anyone lend some guidance here?
     
  2. jdenenberg

    jdenenberg EE Professor

    Joined:
    Nov 21, 2005
    3,831
    1,825
    1
    Location:
    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    The standard Prius (non-touring) used 185/65R15 tires. You can alternatively use 195/60R15 since they basically have the same circumference, but are a bit wider. using 195/65R15 will work, but will change the calibration of your Odometer and Speedometer by about 2% (speedo will read lower).

    JeffD
     
  3. Hal W

    Hal W New Member

    Joined:
    Sep 26, 2010
    872
    53
    0
    Location:
    Grand Forks,B.C. Canada
    Vehicle:
    2006 Prius
    Model:
    II
    I put 195/65/R15 tires on mine. Next time I will go back to 185/65/R15. Runs about 3 mph low and the steering does not feel as precise! Hal
     
  4. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
  5. markaw

    markaw Junior Member

    Joined:
    May 12, 2010
    8
    1
    0
    Location:
    NY
    Vehicle:
    2007 Prius
    Model:
    IV
    I'm thinking about getting Hankook Optimo H727 for my 2009 Prius (live in NY & VT).
    They don't make 185 65 15s, but do make 195 60 15.
    What might I expect by changing to this size from my OEM 185 65 15's
    Many thanks
    Mark Williams
     
  6. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Because the tire is shorter you can expect to throw your speedometer off a bit more than it is stock. So you may read 3mph too fast rather than 2mph too fast. Your MPG indicator might also be off a little more as well. It may read higher than actual (the gauge is already about 2% optimistic). Other than that there should be no issues. You will not harm the car.

    Use this calculator to figure out what to expect when changing tire sizes.
    Tire Size Calculator - tire & wheel plus sizing
     
    1 person likes this.
  7. LIPriusFreak

    LIPriusFreak Can I haz JDM?

    Joined:
    Apr 30, 2011
    449
    34
    0
    Location:
    Long Island, NY
    Vehicle:
    2006 Prius
    Model:
    N/A
    you can expect better handling and a better footprint. they also seem to fill out the wheel wells better.
     
    2 people like this.
  8. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Except that it is a slightly shorter tire which will result in more wheel well gap. I doubt it would be noticeable though. :) Thanks for adding the other benefits. I sometimes forget to do that. lol
     
    1 person likes this.
  9. LIPriusFreak

    LIPriusFreak Can I haz JDM?

    Joined:
    Apr 30, 2011
    449
    34
    0
    Location:
    Long Island, NY
    Vehicle:
    2006 Prius
    Model:
    N/A
    I actually find my prius with less gap if u can believe it.....but 82k saggy springs help my wheel gap issue :D
     
  10. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    I believe it. My 134,000 mile springs were sagging worse than Kriss Kross!

    [​IMG]
     
  11. LIPriusFreak

    LIPriusFreak Can I haz JDM?

    Joined:
    Apr 30, 2011
    449
    34
    0
    Location:
    Long Island, NY
    Vehicle:
    2006 Prius
    Model:
    N/A
    don't hate....I still have warm it up on my ipod :cool:
     
  12. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    It's on my flashdrive... Believe it or not they made it on a 250 Hits of the 90s CD. lol
     
  13. sktn77a

    sktn77a Member

    Joined:
    Apr 28, 2007
    294
    13
    0
    Location:
    NC
    Vehicle:
    2005 Prius
    I used 205/60x15 on my 05 Prius standard for a few years. Handled and braked better but the ride quality and mileage took a hit.
     
  14. calin8a

    calin8a New Member

    Joined:
    Oct 11, 2011
    4
    0
    0
    Location:
    Sacramento
    Vehicle:
    2011 Prius
    Model:
    Four
    New to the site and to the hybrid world in general but was curious if there are any concerns with mpg by changing tire sizes from factory: p195/65r15 to a bit wider style such as p215/60r15... any feedback is appreciated.
     
  15. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Yes, the wider the tire the more rolling resistance. Higher rolling resistance will cause a reduction in mpg. Some people do go wider for various reasons but I believe they go with a 205/60/15 but this size is actually smaller than an identical tire in the oem size. The 215/60/15 would be a tad larger than oem but may help correct the speedo error at higher speeds. It's off by 1-2 mph above 50mph. Expect to take a mpg hit with such a wide tire though.

    My 215/45/17s drop my mpg by at least 6 mpg compared to my 185/65/15s. Wheels weight the same as stock 15s.
     
  16. calin8a

    calin8a New Member

    Joined:
    Oct 11, 2011
    4
    0
    0
    Location:
    Sacramento
    Vehicle:
    2011 Prius
    Model:
    Four
    Thanks for the reply. I was also under the impression that Prius V comes with 17" wheels, and also wider tires... does that mean that particular model is less efficient than the others? I was just curious. Thanks again.
     
  17. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,080
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    The V does come with 17s and yes it's less efficient. In every case where someone has upsized their wheels they have taken an approx 4+/-mpg hit. Those who claim otherwise usually do not track their mpg as accurately as those who observe the loss. I'm still waiting for a knowledgeable and reliable person to swap out the 17s on a V for a set of 15s and do a mpg test and not unreliable casual observations.
     
  18. calin8a

    calin8a New Member

    Joined:
    Oct 11, 2011
    4
    0
    0
    Location:
    Sacramento
    Vehicle:
    2011 Prius
    Model:
    Four
    hmm... that should be a very interesting test to perform. I would be quite interested as well if those results are actually published to learn from real world experience. Anyway, the information was very helpful!
     
  19. uart

    uart Senior Member

    Joined:
    Sep 7, 2009
    4,215
    1,200
    0
    Location:
    Australia
    Vehicle:
    2005 Prius
    Hi Calin. The factory standard size in the US is 185/65. Going to 195/60 is a slightly wider upgrade tire that has approximately the same (though very slightly higher) revs per mile.

    BTW. 195/60 is actually the standard size tire in some countries, including Australia.
     
  20. sidecar

    sidecar Member

    Joined:
    Dec 29, 2010
    342
    44
    0
    Location:
    Australia
    Vehicle:
    2008 Prius
    Model:
    II
    Its possible that there are a few colluding factors that make this more cloudy than it should be.

    1/ The thing that disturbs me most is the possibility that someone moves from 15" equipment to 17" equipment, and doesnt allow for the new rubber to be broken in.

    2/ The next thing would be poor choices in tyre diamters that effect speedometer and mileage readout.

    3/ The quality of the test regime overall, and consistency of application.

    one sure way of sorting this out is to get a co-pilot aboard with a good stop watch. Run some 1/4 or 1/8th mile times, say around 10 to even out reaction times, remove any flyers in the data. That removes any dependence on readout data

    With the usual caveats on equipment selection, if it takes longer with bigger wheel equipment then we know with certainty a performance difference in mileage to account for.