Strange tire mystery

Discussion in 'Gen 5 Prius Main Forum' started by Templeton, Oct 19, 2025 at 2:36 PM.

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  1. VelvetFoot

    VelvetFoot Member

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    Per Tire Size Calculator:


    upload_2025-10-19_19-23-32.png

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    The 215/55/R17 are closer in diameter to oem 195/60/R17 than the oem195/50/R19's are.
     
    #21 VelvetFoot, Oct 19, 2025 at 7:26 PM
    Last edited: Oct 19, 2025 at 7:41 PM
  2. Gokhan

    Gokhan Senior Member

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    With the OEM Dunlop Enasave tires, the speedometer calibration is 100% accurate at all speeds on my Gen 4 Prius Prime, every speed (except when approaching zero) being indicated exactly 2 mph higher than the actual speed.
     
    #22 Gokhan, Oct 19, 2025 at 7:28 PM
  3. Trollbait

    Trollbait It's a D&D thing

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    Sounds like this is a case of the specific tire size not being used enough in the US, so it simply isn't stocked here. The gen5 tire sizes are vexing for owners here, but they are more common in Japan. Owners there don't have the same issue with the sizes.
    Regulations specify the error limit between actual speed and displayed speed. The OEM sizes are close enough that adjusting the speedometer isn't needed to stay in that range.

    As for using wider tires, Toyota choose 195 because thinner tires have better aerodynamics. Wider tires may improve performance, but they will reduce efficiency. If I had a gen5, I'd be kicking around the idea of trying the 175 wide tires made for the i3.
     
    #23 Trollbait, Oct 19, 2025 at 7:51 PM
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  4. Templeton

    Templeton Member

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    I am mostly hoping to get a slightly higher sidewall than stock, but without going much wider than stock. But l never thought of going narrower. Good idea. I wonder if 185mm tires will fit stock LE/SE rims well? But, now , as l look, 185/65R17 tires (which would be a great replacement, size-wise) aren't readily available either ... :(
     
    #24 Templeton, Oct 19, 2025 at 8:15 PM
  5. Blackat

    Blackat Active Member

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    Handling much improved. I drive a lot of windy mountain passes here in Colorado.
    Insignificant loss in fuel economy.
     
    #25 Blackat, Oct 19, 2025 at 8:31 PM
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