never over inflating my tires again

Discussion in 'Gen 2 Prius Fuel Economy' started by oil_burner, Apr 3, 2019.

  1. oil_burner

    oil_burner Member

    Joined:
    Feb 26, 2017
    210
    94
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    I've always run my tires overinflated, to about 38psi in the front and 40psi in the back. After 2 sets of tires being worn out prematurely I am not doing this ever again. The tires end up being worn bald in the middle while the sides have plenty of usable tread left, but I'm not going to run them under inflated to use up that extra tread. Not to mention the extra wear and tire from the beating that the suspension takes. Today I had replace 4 tires where the edges still had probably 7000 miles of life left but the center was down past the wear bar. A set of tires these days costs around $600, not worth it.
     
  2. will the engineer

    Joined:
    Feb 13, 2019
    163
    74
    0
    Location:
    LA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    Thank you for the reminder!

    something so simple we all know, but still we goof up on.

    Posted via the PriusChat mobile app.
     
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    1,432
    1,281
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    It was different when that 7000 miles worth of gasoline cost more...
     
  4. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    3,028
    2,203
    0
    Location:
    New England
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    Recommended tire pressure is clearly displayed on the plate for a reason. That said, 38psi and 40psi don't seem to be that high. Just curious, what tires were you using?
     
    Montgomery and Raytheeagle like this.
  5. Mendel Leisk

    Mendel Leisk Sidewalk Supervisor

    Joined:
    Oct 17, 2010
    32,646
    21,631
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    It's a little odd to be setting the rear tire pressures higher than the front, just saying.

    I'm a little incredulous that modest overinflation would result in the centres balding-out before the edges; I thought that was a thing of the past with radial tires? I wonder if your pressure gauge was off; you're even higher pressures than you thought??

    Maybe too: running singificantly overinflated all the time, might be prematurely wearing out suspension and wheel bearings??
     
    mikey_t, WilDavis, Montgomery and 3 others like this.
  6. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    77,907
    32,894
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    how many miles did you get out of each set?
     
    Raytheeagle and fuzzy1 like this.
  7. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    11,975
    5,604
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    To repeat Bisco: how many miles to you get on both those set?

    Also, before the tires are actually out of reach, can you measure and tell us actual tread depths and differences, center to edge? This, along with the actual tire model and treadwear rating, will be very helpful in future discussions. Plenty of people don't experience this problem at these and even higher pressures. Normal radial tires are not supposed to do this, it was more of an old-style bias-ply tire issue.
     
    skayaks, Montgomery and jerrymildred like this.
  8. Usle

    Usle Member

    Joined:
    Sep 21, 2018
    300
    124
    0
    Location:
    Me
    Vehicle:
    2018 Prius Prime
    Model:
    Plug-in Advanced
    Bias ply tires used to wear out the center before the edges if you overinflated, radial tires... don't, what tires are u using, are they bias?

    Are you talking 200,000 miles on a set of tires?

    It seems no other prius driver that inflates 42 front 40 rear has reported the same results, more input is required.
     
  9. john1701a

    john1701a Prius Guru

    Joined:
    Jan 6, 2004
    11,277
    4,115
    52
    Location:
    Minnesota
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Overinflating means they exceed the cold PSI rating. 38 is well within the 44 PSI for the typical tire.

    I have been running 44 PSI for over a decade and most definitely have not see uneven wear. Sometime about your driving location... or road texture/temperature... or the way pressure is measured... or the frequency of rotation... or the tire itself isn't being told.

    What specifically is on your car?
     
    #9 john1701a, Apr 3, 2019
    Last edited: Apr 3, 2019
    Shtftrucker, benagi and 3PriusMike like this.
  10. 3PriusMike

    3PriusMike Prius owner since 2000

    Joined:
    Jun 21, 2009
    1,970
    1,249
    0
    Location:
    Silicon Valley
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Same for me. 42 to 44 psi since my 2001 Prius. The only early replacement I've had has been due to tire damage, A nail hole too close to the side to plug and a bubble from curb damage.

    Mike
     
    Raytheeagle likes this.
  11. oil_burner

    oil_burner Member

    Joined:
    Feb 26, 2017
    210
    94
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    my tires are Goodyear assurance 195/50/15. I wish I could measure but they are gone already. I ran lower in the front because of comfort, potholes and cracks don't hit the front end as hard and in the rear I wouldn't feel it much. Unfortunately I did not keep track of the exact mileage on them since I rotate between winter tires and all seasons each year, but I believe they only lasted about 20k miles. I went back to ecopias again this time and I immediately noticed much lower rolling resistance. So I guess the lesson is if you want better fuel economy then buy ecopias.

    I had the exact same experience with my pickup truck using Michelin LTX tires that I kept around 45psi cold, in an effort to get better fuel economy. Those also wore very unevenly, in the same manner.

    my tires looked like this photo, which is obviously a radial tire, nobody uses bias ply tires these days. [​IMG]
     
    #11 oil_burner, Apr 3, 2019
    Last edited: Apr 3, 2019
    bisco likes this.
  12. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    3,345
    1,687
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2006 Prius
    I beg to differ. I did report such a thing, but got dismissed with similar rhetoric as has been posted here.

    Most people that do this (overinflated) do not measure their tires on a regular basis (as I did when collecting my data) and would probably not even notice that that the wear was uneven. They'd just accept the information from whoever was telling them their tires were worn out and needed replacing.

    Radials might be more resilient that bias tires, but they will still wear in the centre if over-inflated, it just maybe too subtle to notice without measuring.

    For the record, I can get 60+ MPG with the standard inflation.

    I think that for most people it is wishful thinking, placebo effect if you will, mostly due to the fact, that when they paid no attention to their tires, they were, more than likely, on average running under-inflated so when they start paying attention and they over-inflate, miraculously they are getting "much better" gas milage.

    When coming back down (in steps) to placarded from a high of running 42/40, I noticed no real measurable difference in MPG.

    I have also observed that same difference between GY Assurance and Ecopia, although our versions of both are different variations to the those available in NA.

    As they say YMMV.
     
    #12 dolj, Apr 3, 2019
    Last edited: Apr 3, 2019
  13. oil_burner

    oil_burner Member

    Joined:
    Feb 26, 2017
    210
    94
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    for example here is quick calculation,

    for 20,000 miles on these tires lets say I was able to average 42mpg instead of 40mpg by over inflating.
    the fuel cost at $3/gal is $1428 instead of $1500. I saved some $72.

    I think I could have gotten around 30,000 miles on the tires if they wore evenly. The tires cost me ~ $600 installed. So I lost 1/3 of the value by throwing them out prematurely, which is $200. On top of that I had to endure 20k of jarring, uncomfortable ride and suspension wear. And, there are 4 tires needlessly in a landfill somewhere.
     
    benagi, will the engineer and dolj like this.
  14. padroo

    padroo Senior Member

    Joined:
    Jan 11, 2008
    2,732
    2,175
    13
    Location:
    Chesterton, Indiana Another third world country.
    Vehicle:
    2016 Prius
    Model:
    Four
    Once the tire pressure gets to a certain point I would think the MPG gains would be minimal but what would that number be?
     
    ALS and will the engineer like this.
  15. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    3,345
    1,687
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2006 Prius
    36-37 IMHO.
     
  16. AKCoffee

    AKCoffee Junior Member

    Joined:
    Jan 14, 2016
    46
    22
    0
    Location:
    Minnesota
    Vehicle:
    2014 Prius v wagon
    Model:
    Two
    Cronic over-inflater here. Last three sets of tires lasted at least 75k miles no abnormal wear. 2 of the sets on our Civic Hybrid @ 55 psi all around. That level hands out too much abuse in my PIP, now I'm strictly 45 year round...good for a couple of MPGS between 55 and 65 mph.
     
  17. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    11,975
    5,604
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    Which Assurance model?
    "Tire Line Construction Tire Size Ratings
    Traction* Temperature** Treadwear***
    Assurance All Season Radial All Sizes A B 600
    Assurance Authority (H&V) Radial All Sizes A A 580
    Assurance Authority (T) Radial All Sizes A B 620
    Assurance Comfortred Radial All Sizes A B 700
    Assurance Comfortred Touring (T&H) Radial All Sizes A B 740
    Assurance Comfortred Touring (V) Radial All Sizes A B 640
    Assurance CS Fuel Max Radial All Sizes A B 600
    Assurance CS Tripletred Radial All Sizes A B 740
    Assurance Fuel Max (H/V) Radial All Sizes A A 580
    Assurance Fuel Max (S) Radial All Sizes A B 540
    Assurance Fuel Max (T) Radial All Sizes A B 620
    Assurance Touring (H) Radial All Sizes A A 580
    Assurance Touring (T) Radial All Sizes A B 620
    Assurance Tripletred (H) Radial All Sizes A B 740
    Assurance Tripletred (T) Radial All Sizes A B 740
    Assurance Tripletred (V) Radial All Sizes A A 640
    Assurance Ultratour Radial All Sizes A B 620
    Assurance Weatherready Radial All Sizes A A 700"

    The lowest treadware rating in that line looks like 540, which should produce vastly more than 20k miles, or even 20k+7k miles. In modern times I've never had tread wear out that quickly, even with shorter treadwear ratings and higher pressures than you mention.
     
    Raytheeagle likes this.
  18. oil_burner

    oil_burner Member

    Joined:
    Feb 26, 2017
    210
    94
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    I had the standard assurance all season. Again just a rough estimate on 20k, but mileage always varies depending on driving conditions, pavement, etc. We have very rough pavement here with lots of frost heaves, potholes, etc. Each day I go down a 2 mile gravel road that they sometimes put fresh crush over that is sharp. That is not counting for wear and tear on the suspension components either. You can use this calculator to see the cost savings:
    Fuel Cost Calculator

    for example for 60k miles at 45mpg costs $4000, 47mpg costs $3830 saving you just $170.

    For those who have run overinflated tires for a considerable amount of time, please share a picture of your tire tread by turning your front wheels so you can see the surface. I would be very surprised if you didn't see abnormal wear.
     
    #18 oil_burner, Apr 4, 2019
    Last edited: Apr 4, 2019
  19. Rmay635703

    Rmay635703 Senior Member

    Joined:
    Oct 16, 2016
    1,054
    663
    0
    Location:
    Somewhere in Wisconsin
    Vehicle:
    2013 Chevy Volt
    Model:
    N/A
    At 60psi and 50,000 miles the edges wore off but the center had plenty of tread.

    This was on Goodyear assurance energy savers
     
  20. Sanjay Goel

    Sanjay Goel Member

    Joined:
    Feb 13, 2018
    76
    48
    0
    Location:
    Dallas, TX
    Vehicle:
    Other Hybrid
    Model:
    N/A
    :confused::confused::(
     
Loading...