Prius v (Wagon) OEM tire RPM and speedometer accuracy

Discussion in 'Prius v Accessories and Modifications' started by dhanson865, Oct 27, 2011.

  1. dhanson865

    dhanson865 Expert and Devil's advocate

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    Prius v (Wagon) OEM tire RPM and speedometer accuracy 16" & 17"

    From a thread in the Gen III forum member "Bigfan" kindly gave us the OEM tire info from his new v (Wagon).

    I looked up the tire info on tirerack and it appears that the revs per mile (RPM) of the OEM 16" tire is 811

    "Bridgestone Turanza EL400 02 P205/60R16 91v" 811 RPM 25.7"
    51 PSI max with UTQG of 260 A A 23 pounds

    okay, looks like the 17" OEM tire is

    P215/50R17 Toyo Proxes A20

    Toyo isn't sold on tirerack.com and I haven't found the diameter or revs per mile for this tire yet.

    OEM 16" #1 811 205/60/16 Bridgestone Turanza EL400-02
    OEM 16" #2 8?? 205/60/16 Yokohama BluEarth S34
    OEM 16" #3 810 205/60/16 Michelin Energy Saver A/S

    OEM 17" #1 8?? 215/50/17 Toyo Proxes A20

    I'll edit this post as info comes in as to speedometer accuracy and what the desired RPM is to correct the speedometer if needed.
     
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  2. dhanson865

    dhanson865 Expert and Devil's advocate

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    added what little info I have about the 17" tire (P215/50R17 Toyo Proxes A20)

    interestingly enough it seems to have removed or hidden the thanks to the post when I edited it.
     
  3. dhanson865

    dhanson865 Expert and Devil's advocate

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  4. F8L

    F8L Protecting Habitat & AG Lands

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    I found a little bit of info on those tires. Interestingly they use orange peel oil just like dB Super E-Spec tires!

    Toyota Taps Yokohama BluEarth Tires For New Prius v Crossover

    Cool Fuel Efficiency Tire Tips from Yokohama
    [ame=http://www.youtube.com/user/YokohamaMotorsports#p/u/15/bJHVabIDtoE]YokohamaMotorsports's Channel - YouTube[/ame]
     
  5. dhanson865

    dhanson865 Expert and Devil's advocate

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    810 205/60/16 Michelin Energy Saver A/S
     
  6. dhanson865

    dhanson865 Expert and Devil's advocate

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  7. Mike James

    Mike James Camaros and Prii go figure

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    I hate to burst your bubble. Revs per mile is not an exact measurement. There are too many variables that are hard to control. Examples tread wear, air pressure in tire, vehicle load, and rotational speed.

    I also highly doubt all tire manufacturers across USA, EU, and JP use the same methods for calculating or measuring revs per mile.

    Here is a fun experiment for you. Drive through a small puddle of water at <5 MPH. The tires will leave marks on the dry pavement from the part of the tire that got wet. Measure the distance from the start of the first water mark to the start of the second water mark in inches. There are 63360 inches in a mile. Divide 63360 by your measurement to get revs per mile. Now drive through another small puddle of water at >45 MPH. Measure again, you will find the distance is longer due to the tire growing with increased rotational speed.

    Now run the same experiment with the tire air pressure changed by 5 psi, another one of the many variables that cause us to have a 2.5% tolerance on the speedometer. This is why radar guns and GPS measurements are much more accurate.
     
  8. F8L

    F8L Protecting Habitat & AG Lands

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    Mike, while what you are saying is true revs/mile is still an important measurement to consider when buying your tires. If your tire has less revs per mile than your previous tire then you may erroneously assume you are getting worse mpg when in fact you may not be. Then we must consider speedometer readings with different size tires. A few revs per mile may go unnoticed but change it enough and the speedometer reading will change as well. I've observed this on my car when swapping tires. I also notice that the speedometer gradually becomes less accurate the faster you go. Like you mentioned above.
     
  9. dhanson865

    dhanson865 Expert and Devil's advocate

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    You aren't busting my bubble. I already knew that.

    I guess it's time to quote myself from another thread

     
  10. dhanson865

    dhanson865 Expert and Devil's advocate

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    Please don't get us started on radar guns in this thread, take that to the off topic (freds house of pancakes forum).

    As to accuracy I'd rather see 5th wheel testing but I'll take GPS as a practical low cost substitute for those of us that don't have access to expensive test equipment.
     
  11. dhanson865

    dhanson865 Expert and Devil's advocate

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    It's been about 6 months since this thread was created. Still looking for someone with a GPS to test their speedometer accuracy.

    In the mean time I'll post the list from another thread of aftermarket tire choices. I haven't updated the list in months, might do that in the future.

    I don't have accuracy data yet so I'm listing tires in the range of 795 to 825 RPM until we have data.


    v (Wagon) ~810 RPM 15" Tires

    823 215/55/15 Michelin Primacy MXM4 with Green X
    822 205/65/15 Michelin Hydroedge with Green X
    821 205/65/15 Goodyear Assurance Fuel Max
    820 205/65/15 Goodyear Assurance ComforTred Touring
    818 205/65/15 Continental ContiProContact (Grand Touring All-Season)
    818 205/65/15 Kumho Solus HM KR22
    816 205/65/15 Hankook Optimo H727
    815 205/65/15 Yokohama AVID ENVigor
    806 215/65/15 Michelin Hydroedge with Green X
    797 205/70/15 Michelin Hydroedge with Green X
    79x 205/70/15 Goodyear Assurance Fuel Max (maybe 795 RPM?)


    v (Wagon) ~810 RPM 16" Tires

    824 215/55/16 Continental ExtremeContact DWS (Ultra High Performance All-Season)
    824 215/55/16 Continental ContiProContact (Grand Touring All-Season)
    823 215/55/16 Michelin Pilot Sport A/S Plus (Ultra High Performance All-Season)
    820 215/55/16 Yokohama AVID ENVigor
    814 205/60/16 Goodyear Assurance ComforTred Touring
    814 205/60/16 Goodyear Assurance Fuel Max
    812 205/60/16 Bridgestone Ecopia EP422
    811 205/60/16 Bridgestone Turanza EL400-02
    811 205/60/16 Continental ContiProContact (Grand Touring All-Season)
    811 205/60/16 Kumho Solus HM KR22
    810 205/60/16 Michelin Energy Saver A/S
    810 205/60/16 Yokohama AVID ENVigor
    808 205/60/16 Continental ProContact with EcoPlus Technology (Standard Touring All-Season)
    807 205/60/16 Hankook Optimo H727
    800 215/60/16 Michelin Hydroedge with Green X
    800 215/60/16 Goodyear Assurance Fuel Max
    797 215/60/16 Michelin Primacy MXV4 with Green X (make sure it's marked Green X)
    797 215/60/16 Bridgestone Ecopia EP422
    797 215/60/16 Continental ContiProContact (Grand Touring All-Season)
    796 215/60/16 Michelin Energy Saver A/S
    790 205/65/16 Goodyear Assurance Fuel Max


    v (Wagon) ~810 RPM 17" Tires

    825 205/50/17 Continental ExtremeContact DWS (Ultra High Performance All-Season)
    818 215/50/17 Continental ContiProContact (Grand Touring All-Season)
    817 215/50/17 Bridgestone Ecopia EP422
    815 215/50/17 Michelin Primacy MXM4 with Green X
    815 215/50/17 Yokohama AVID ENVigor
    807 225/50/17 Goodyear Assurance Fuel Max
    805 225/50/17 Continental ContiProContact (Grand Touring All-Season)
    803 225/50/17 Michelin Energy Saver A/S
    803 225/50/17 Michelin Primacy MXM4 with Green X
    803 225/50/17 Michelin Pilot Sport A/S Plus (Ultra High Performance All-Season)
    795 215/55/17 Goodyear Assurance Fuel Max
     
  12. blisspacket

    blisspacket Junior Member

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    My first question: this thread dates 2012. Is this subject so dead there's been no newer info????

    Two Prius V 2015 sidebyside: ours is a V 5, bros is V 3. Ours has 215/50-17 W tires; his has 60-16 tires. Our calipers showed his tire dia. about 5/8" GREATER than the V 5. Likewise his height was about 1/2" higher than the V 5.

    Searching for a smoother quieter ride. I'm Contemplating putting 60 ratio tires on the V 5 17" wheels to raise it (comfort in and out) and provide more flex/cush to the ride in general. I recognize that might throw the speedometer off. Any hard data out there from those who've been here, done that??
     
  13. rjparker

    rjparker Senior Member

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    First, I find that ride comfort can vary widely with tire brand. I always use Michelin and find the ride and road noise better than most OEM tires of the same size.

    Changing to a different sidewall and tire width:
    There will be a change on your speedometer directly related to the circumference of the tires. The existing accuracy is pretty good and highly repeatable based on radar signs I routinely go by. Usually my Prius v3 is about 1-2 miles high depending on speed. Perhaps 1 mph at 30 and 2 mph at 60 (~3.3%). Some suggest it is intentional to keep you closer to the limit. There are enough radar speed signs that show me the number is repeatable.

    With a larger circumference tire, a speedometer will display a lower speed and the odometer will show less distance traveled. Doing a little "back of the napkin" math seems to show that replacing a Michelin 215/50/17 at 815 rpm (revs per mile) with a Michelin 215/60/16 at 800 rpm (and 16" wheels) will result in a larger circumference tire that covers more ground with each revolution. This would decrease the speedometer by ~1.84% over what it reads now. It could actually help calibrate a high reading speedometer. Regardless, 1.84% only represents a change of 1.1 mph at 60 mph which is not significant. Especially considering older electro-mechanical speedometers were often off by +/- 5%.

    A second option would be a 215/60/17 at 766 rpms, assuming it would fit the wheel well. Now we are talking a speedometer decrease of ~6% which might be noticeable.

    For reference, the examples were all Michelins with data from Tirerack.
    Diameters: 215/50/17 OEM = 25.5"; 215/60/16 = 26.1" ; and 215/60/17 = 27.2"
    Add from Air_Boss below: 225/50R/17 = 25.9" at 803 rpm

    speedsign.gif
     
    #13 rjparker, Mar 14, 2019
    Last edited: Mar 14, 2019
  14. Air_Boss

    Air_Boss Senior Member

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    We went with 225/50R17 which at 3% larger circumference just about perfectly square-up the indicated with the GPS road speed indication.
     
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