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Low Rolling Resistance replacement tires: Current List

Discussion in 'Gen 3 Prius Fuel Economy' started by F8L, Apr 17, 2011.

  1. F8L

    F8L Protecting Habitat & AG Lands

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    The treadwear value is the manufacture's treadlife indicator. Because the rating is not universal in testing parameters you cannot compare this rating across manufactures. I think using the rating as a general guide then comparing warranties is the best method. If a manufacture rates a tire at 800 but only offers a 50,000 mile warranty I would suspect the tire will not last very long. Conversely if a tire is rated at 440 but offers a 60,000 mile warranty then it is probably a long-life tire.

    For more information please see Tire Rack's explanation.

    Tire Tech Information - Uniform Tire Quality Grade (UTQG) Standards

    I will update the list to reflect the specific Hankook tire so there is no mix up. Thanks for the help. :)
     
  2. txl146

    txl146 Member

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  3. F8L

    F8L Protecting Habitat & AG Lands

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    I will add them as they are a Prius OE tire, however, I would not recommend them due to their lower treadwear rating a traction rating of B B. There are much better tires available. Thanks for bringing them to my attention though. It's people like you that are helping make this list useful. :)
     
  4. Britprius

    Britprius Senior Member

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    F8L thanks for all the work you are doing with the LRR tyre list. One small correction the Kumho KR22 is AA rated not AB 15inch and above. Will keep you updated on the Hankook K425's when I have them run in but I definitely have not lost any MPG with new tyres at a greater width.
     
  5. F8L

    F8L Protecting Habitat & AG Lands

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    Thanks! I'll verify then correct the mistake. I'd like to start adding the Euro tires as well so any info you can provide is helpful. :)
     
  6. Britprius

    Britprius Senior Member

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    F8L Any LRR tyres I come across in the UK that you do not list I will inform you of. We do not get the 15inch wheels here only 16&17, and there are very few 195/55/16 tyres available but a large selection in 205/55/16 witch are also much cheaper. EG Michelin ES 195/55/16 £93.67 Michelin ES 205/55/16 £61.81 and at that tyre dealer 31 tyre available at 195, 103 tyres available at 205. 20% tax to be added to those prices witch makes the difference even greater.
     
  7. F8L

    F8L Protecting Habitat & AG Lands

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    I'd very much appreciate the help. I would like this list to be helpful to our friends across the Atlantic. :)

    I 'lladd the non- oem sizes as well and label them such that people understand how their speedometer will change due to tire size.

    Justin
     
  8. Britprius

    Britprius Senior Member

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    The over size tyre helps correct the existing speedometer error of between 2&3mph at 30mph it also should correct the small MPG error calculation on the MFD.

    John.
     
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  9. dhanson865

    dhanson865 Expert and Devil's advocate

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    In fact we don't know the exact revs per mile to achieve accuracy. It'd be nice if someone with a Gen 2 and the proper gear (tirerack or some other company) would do the tests and see what the actual revs per mile should be. Per F8L we know 844 is close but we don't know if the actual number is above or below that. For the sake of erroring on the side of the OEM 855 I'm assuming the correct number is between 844-850 but for the sake of math for now I'm using 845 as the exact number.

    If OEM stock tires for 2004-2009 Prius are 855 revs per mile and 845 makes the display accurate anything in the 835-840 range is going to be similar error as OEM tires and anything below 835 will be a worse error in the other direction.


    These won't correct 2004-2009 speedometer error at 195/65/15

    Hankook Optimo H426 (All-Season Grand Touring) * T rated tire is LRR

    Michelin Energy Saver A/S (All Season)

    Michelin Energy MXV4 S8 w/GreenX (All Season)

    Kumho eco Solus HM KR22 (All Season)**

    Hankook Optimo H727 (All Season) reported to be great in snow

    Goodyear Assurance Fuel Max (All Season)***

    Continental ContiProContact (All Season)****

    Continental ProContact with eco Plus (All Season) *****

    Bridgestone Ecopia EP422 (All Season) ******

    Yokohama dB Super E-Spec (Summer Tire)

    Nokian eNTYR (All Season)*******


    ** For the Kumho eco Solus HM KR22 you would instead need to use 205/60R15 which is 844 vs the 834 of the 195/65/15. Going to 205/60/15 on this tire would make the display more accurate.

    *** For the Goodyear Assurance Fuel Max you would instead need to use 205/60R15 which is 847 vs the 836 of the 195/65/15. Going to 205/60/15 on this tire would make the display more accurate.

    **** For the Continental ContiProContact you would insted need to use the 185/65R15 which is 842 vs the 835 of the 195/65/15.

    ***** For the Continental ProContact with eco Plus you would instead need to use 205/60R15 which is 841 vs the 831 of the 195/65/15. Going to 205/60/15 on this tire would make the display more accurate.

    ****** For the Bridgestone Ecopia EP422 you would insted need to use the 185/65R15 which is 852 vs 833 of the 195/65/15

    ******* For the Nokian eNTYR you would insted need to use the 185/65R15 which is 851 vs 831 of the 195/65/15


    In short the 2004-2009 Prius with a 15" rim is best served with a tire nearest the 845 mark regardless of the xx5/xx marking.

    Assuming 845 is the accurate mark the most accurate tires for a 2004-2009 Prius with 15" rims are

    844 205/60/15 Kumho eco Solus HM KR22
    847 205/60/15 Goodyear Assurance Fuel Max
    843 185/65/15 General Alimax HP#
    842 195/65/15 Michelin HydroEdge w/ Green X (All-Season)
    842 185/65/15 Continental ContiProContact###
    848 185/65/15 Continental ProContact with eco Plus###
    851 185/65/15 Nokian eNTYR
    850 185/65/15 Yokohama AVID ENVigor##

    # Not billed as a LRR tire but is a tire I've used on other cars and would consider for my Prius.

    ## The rolling resistance of the AVID ENVigor is unkown to me but these are the tires on my 2005 Prius currently.

    ### Please note that the ContiProcontact and the ProContact with eco Plus are confusingly similar names with differing sizes to get the same accuracy.

    Or if we sort by revs per mile we get

    851 185/65/15 Nokian eNTYR
    850 185/65/15 Yokohama AVID ENVigor##
    848 185/65/15 Continental ProContact with eco Plus###
    847 205/60/15 Goodyear Assurance Fuel Max
    844 205/60/15 Kumho eco Solus HM KR22
    843 185/65/15 General Alimax HP#
    842 195/65/15 Michelin HydroEdge w/ Green X (All-Season)
    842 185/65/15 Continental ContiProContact###
    841 205/60/15 Continental ProContact with eco Plus###



    @F8L
    These two quotes contradict each other

     
  10. dhanson865

    dhanson865 Expert and Devil's advocate

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    Using the 1010tires size calculator I get revs per mile of

    850.3 185/65/15
    842.7 205/60/15
    832.6 195/65/15

    My initial reaction to this was to assume if 855 Revs per mile made the gauges inaccurate by a small amount then 850 would be the reasonable target based on the OEM tire size of the 2004-2009 Prius.

    When F8L said 844 seemed accurate to him I might consider 843 as the closest match out of the 1010tires size calculator but it isn't exactly a commonly used size on the 2004-2009 Prius.

    It's a shame the auto/tire industry is so keyed on xxx/xx/15 designations instead of just listing the correct revs per mile on the car sticker/owners manual in addition to the OEM tire size.

    Heck it'd be nice if the tire manufacturers printed the revs per mile on the sidewall just like they do max pressure.
     
  11. xpcman

    xpcman Senior Member

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    TireRack does not list Michelin HydroEdge w/ Green X in either 185x65 or 195x65.
    Do you think 205x60 would give a harsh ride in my 2010?
     
  12. F8L

    F8L Protecting Habitat & AG Lands

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    I'm very glad you took the time to work all of this out. When I first started this thread I was stuck on using the tire size as if all were created equal. I found out this is not the case when it comes to revs per mile. When I have some free time I will go through the first post and make corrections and better clarify how revs per mile works so that people can't make better choices. Thanks for your help!
     
  13. Britprius

    Britprius Senior Member

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    I am using 205/55/16 tyre in the UK,195 / 16 inch being the standard Prius wheel size here. The TPM of these tyres is 831 and at this the speedo is still about 1MPH to fast at 30MPH, however my calculated fuel consumption now almost exactly matches that of the MFD.
     
  14. dhanson865

    dhanson865 Expert and Devil's advocate

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    Britprius if it's 1MPH off at 30 is it 2 MPH off at 60?

    I wonder why you compare at 30MPH when I tend to think of it's accuracy at higher speeds?
     
  15. Britprius

    Britprius Senior Member

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    Yes it seems to be a percentage rather than a fixed 1MPH. Sorry for the delay I was having my evening meal. I gave 30MPH as test speed because most of our radar speed signs are set at this making it an easy test.
    I think if I had gone to 205/60/16 the speedo would have been spot on.
     
  16. Britprius

    Britprius Senior Member

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    I should also have said in my reply that I add 2.4% to my odo reading before dividing by gallons of fuel used (pump reading) to give my calculated fuel used. This is because I believe the odo calculates a mile at 851TPM and with the circumference of the 205 tyre at 831TPM the car will have travelled about 127ft further. Hope that is reasonably clear. If I can be of any help just ask.
     
  17. dhanson865

    dhanson865 Expert and Devil's advocate

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    Your posts seem to imply that the revs per mile used by the spedometer is different than the revs per mile used by the odometer or that you assume both use 850 revs per mile.

    If the Prius spedometer uses 850 for the revs per mile and your tire is really 831 then when your Prius says 60 MPH you would really be doing 61.37 MPH or said the other way when you are really doing 60 MPH the Prius would say 58.66. Either way is little more than 1 MPH difference at 60 and should be less than 1 MPH difference at 30.

    I'm specifically concerned with the 2004-2009 US Prius I don't know if there is any variation on spedometer/odometer calibration in revs per mile between generations or between markets.

    edit: just noticed I'm in the thread for Gen III prius and there is a very similar thread at http://priuschat.com/forums/gen-ii-...esistance-replacement-tires-current-list.html for Gen II.

    Rather confusing if you read both threads and then respond to the wrong one. I guess I'll have to be more careful.
     
  18. Britprius

    Britprius Senior Member

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    The speedo of the Prius in the UK reads 10% fast (some obscure EU regulation applies to all vehicles) but odo is correct. The speedo with the oversize tyres will actually read .6mph fast in theory, and the nearest I can check is with road side radar speed signs with a resolution of 1MPH, and the Prius speedo also has this resolution giving 1MPH difference.
    The odometer being correct with OEM tyres will under read with oversize tyres in my case by 2.4%. I believe in the US the Prius speedo and odo have the same characteristics as in the EU but I may be wrong. Hope I have explained this clearly it does get a little complicated.
     
  19. xs650

    xs650 Senior Member

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    My Gen III US edition Prius speedometer reads 1 mph high at 60 mph, a little less than 2% high. The odometer is a lot closer.

    I believe you mentioned that the odometer works on a basis of 851 tire revs/mile? How did you find that out?
     
  20. Britprius

    Britprius Senior Member

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    I cannot be sure of the exact TPM number but from checking OEM tyres fitted to the Prius most seem to be in the region of 848-855, and since my OEM tyres were Bridgestone Turanza's at 851TPM this is what I settled on as being a reasonable figure, but I could be proved wrong, but we have to start somewhere. As stated in my previous post the regulations for speedometers in the UK are some what optimistic (speedo should not reed low but can read 110% of actual speed plus 6.25MPH) which means at true 60mph a speedo can read 72.5MPH so manufacturers generally go for 10% so as not to fall outside the regulations at either end of the scale even if they change tyre manufacturer or rim size. I checked my OEM tyres and speedo accuracy against roadside radar speed signs and found a reliable 10%. The regulations in the US are different see Wikipedia.