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//// Tire comparison : Ecopia 422 Plus VS Goodyear Assurance A/S ////

Discussion in 'Gen 2 Prius Main Forum' started by Andyinchville1, Jul 22, 2020.

  1. Andyinchville1

    Andyinchville1 New Member

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    Hi All,

    I have to replace all 4 tires on my car and figured Prius folks probably have a better understanding and appreciation for trying to get the best MPG's so I figured I'd ask my questions and post my thoughts here.

    My car originally had P195 65 R15 Bridgestone Ecopia 422 Plus tires on them.

    When they wore out, I replaced them with upgraded sized P205 70R 15 Bridgestone Ecopia 422 Plus tires and not only gained a little more ground clearance (good since I do delivery work and sometimes have to go down horrible driveways or gravel roads etc so more ground clearance is a plus) but fuel economy as well ( I mainly do highway drives so I guess the overall higher effective gear ratio makes for better cruising / fuel mileage).

    Anyways, I am in need of 4 new tires and thought about upgrading yet again ...

    My current top pick is 205 75 R15 Goodyear Assurance A/S tires.

    These tires, while not touted as LRR by the manufacturer are about 3% taller than what I am currently running, 2 lbs lighter per tire, and have a sidewall max of 51 PSI VS my current 44 MAX psi Ecopias.

    I had read that it takes approximately a 10% reduction in tire rolling resistance to get about 1 to 2% better fuel economy so part of my thinking is since my proposed tires are about 3 % taller that should nullify any potential benefits of the smaller tires LRR features (i.e. if 3% taller gearing results in a corresponding 3% increase in fuel mileage that would mean the the Ecopias would have to have 30% less rolling resistance to even compete and the bigger tire can STILL go to 51 PSI Vs 44 PSI for the ecopias )

    Do you think the the Goodyears features mentioned above can more than offset the fact that it is not necessarily rated LRR by the manufacturer when compared to the Ecopias ? ( I know it's nearly impossible to compare across brand lines since LRR does not seem to have an industry standard for testing ... only what manufacturers advertise when compared to the other tires the manufacturer makes).

    Has anybody here run these two tires (not necessarily same size but at least makes / models to see what I could expect between the tow tires?).

    Any input / help / recommendations would be greatly appreciated.

    Thanks

    Andrew

    PS - FWIW the tires cost within $3 of each other (ecopias a little cheaper) and have similar the same treadwear warranty (Ecopias 70K , Assurances 65K
     
    #1 Andyinchville1, Jul 22, 2020
    Last edited: Jul 22, 2020
  2. PriusCamper

    PriusCamper Senior Member

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    You lucked out improving MPG by installing larger tires... In most cases Prius don't do well in the MPG department with tires that are not the standard size. What's more the LRR designation makes a huge difference. Almost as much as tire pressure. I use 47psi in front and 45psi in back, which may be a harder ride, but boost MPG and I got an additional 10K miles beyond the expected lifespan of my ecopias... So I'd suggest sticking with same tires you already have and to save money order them online from simpletire.com and slowly swap out the most worn out tire first... I did this last time and it took a year till all 4 tires were replaced and I greatly increased the lifespan of my new tires by doing it this way.
     
    #2 PriusCamper, Jul 22, 2020
  3. Rmay635703

    Rmay635703 Senior Member

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    This seems like a repeat?

    I would buy one tire on a spare rim, mount up front and validate clearance when steering fully left at right, I recall a few cases where that size (taller and wider) hits The inside edge if you both are turning and hit a bump, you then need a spacer in your spring to gain a little more clearance.

    As for economy you will likely loose fuel economy as there is zero gearing advantage on an ecvt and ground clearance creates more drag.

    In the real world you can offset lost economy by adding inflation and driving slower.

    The question is how much,
    if you don’t really care about economy go for it, a larger tire at 51psi will be much bouncier than a proper size at 51psi due to its weight rating
    If ground clearance is most important to you it doesn’t much matter but only a few overseas folks have experimented with tall but not wide tires, so don’t expect many responses

    Buy the tires and report back what you find, you don’t need our validation

    Good Luck
     
    #3 Rmay635703, Jul 22, 2020
    PriusCamper likes this.
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