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Going to add Sumitomos to 2002

Discussion in 'Generation 1 Prius Discussion' started by kmc6566, Sep 28, 2010.

  1. kmc6566

    kmc6566 Junior Member

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    Just an information thread for those looking for information about tires on a Gen I. I am going to put Sumitomo HTR 175/70 R14s on my car. Once they are on I will record what kind of mileage I get. Will also let everyone know what the tires do to the accuracy of the speedometer since the Revs per mile for this tire are not the same as the factory tires. I have attached pictures of my old tires. You will probably yell at me for waiting so long because they were certainly a safety issue. :) Front_driver.jpg

    Front_pass.jpg

    Rear_driver.jpg

    Rear_pass.jpg
     
    #1 kmc6566, Sep 28, 2010
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Glad to hear you are getting new tires. No point in yelling: it's your life and your car.
     
    #2 Patrick Wong, Sep 28, 2010
  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    A good choice! I use the T4s but my understanding is the HTR is every bit as good. Their weight limit also corresponds to the OEM tires that had a special grade needed. I notice there are several grades, now:

    • HTR HR - High Performance All-Season (not in this size)
    • HTR 200 - High Performance Summer (880 revs/mile)
    • HTR T4 - Standard Touring All-Season (886 revs/mile)
    I'm doing an experimental test with 195/70 R14s but not ready to recommend.
    Your old tires show the inner wear I associate with excessive camber.

    Can you post the alignment numbers for all four wheels? We may have to do some adjustment on this side of the Atlantic as we typically see degrees and 1/10ths of degrees. The time for perfect alignment is with new tires, before the wear sets in.

    Any idea of how many miles on the last set of tires?

    Thanks,
    Bob Wilson
     
    #3 bwilson4web, Sep 28, 2010
  4. kmc6566

    kmc6566 Junior Member

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    I'm not in England Bob. I'm in England, Arkansas. And don't ask how I got here. :)

    I just had the tires mounted today. I plan on getting them aligned this weekend and I will post the numbers from the alignment.

    Don't know how many miles on the firestone FR380s that were on the car. I bought the car with about 142K on it. I put about 11,000 on the tires. I don't believe the tires were rotated the way they should be. If I had to guess I bet the tires only had between 30,000 and 35,000 miles on them. But that is just a guess.
     
    #4 kmc6566, Sep 28, 2010
  5. kmc6566

    kmc6566 Junior Member

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    Just wanted to follow up on this thread. The Sumitomo tires revs per mile is lower than the factory tire. As a point of reference I will use 3% as the difference. What that means is your speedometer and odometer will be off by about 3%.

    For instance if the speedometer shows that you are doing 60mph you are really doing about 62mph.

    Your odometer is also off 3% on the low side. For instance for every 100 miles the car shows that you have traveled you have really traveled about 103 miles.

    So if you want to manually calculate your gas mileage for a tank you need to make an adjustment.

    For example if the car shows you have gone 500 miles and you filled the tank with 10 gallons you will need to add 3% or about 15 miles to get a more accurate reading. So in this case you would have gotten 515/10 or 51.5mpg instead of the 50mpg based on the odometer.

    I am really not concerned with the MPH difference as I basically go the speed limit.

    I will follow up with the alignment numbers when I get them.
     
    #5 kmc6566, Sep 29, 2010
  6. kmc6566

    kmc6566 Junior Member

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    Just adding the alignment numbers now that I have them.


    Front Left before after
    camber -.4 -.4
    caster 1.6 1.6
    toe -.04 .0
    SAI 10.2 10.2

    Front Right
    camber -1.1 -1.1
    caster 1.1 1.1
    toe .20 .05
    SAI 10.6 10.6

    Left rear
    camber -1.1 -1.1
    toe .03 .02

    Right rear
    camber -1.2 -1.2
    toe .13 .13

    After alignment and new tires I am now getting about 51-52 mpgs. Before I was getting 47-48mpg.

    Not sure if that is all due to the tires though. I did open up the traction battery and clean the terminals. That seemed to help with the mileage even before I got the tires.

    Just FYI.
     
    #6 kmc6566, Oct 21, 2010
  7. mlibanio

    mlibanio Member

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    I have Sumitomo HTR T4 tires, and they are very good tires for the price. Fuel economy is so improved over the Bridgestones I had previously, and the 51 psi rating means they roll very well. My mpg improved about 3 mpg overall, which is considerable. I used to average about 43 mpg with the Bridestones, but hover around the high side of 46 mpg, which is great for me, considering I absolutely never drive for economy. I just drive my Prius the same way I drive my 2002 Chrysler Neon.

    A few things to note, dry weather handling is excellent, and the car handles very predictably. Running at 51 psi for about 20,000 miles have had no issues with cupping. Braking is good although I have noticed a slight tendency to wander on heavy braking that was not there with the Bridgestones or my Michelin Alpine winter tires.

    Wet weather handling is good, although, if you push the tires a little above normal, it tends to slide, but that is more attributable to our Prius' high centre of gravity more than anything. But overall quite good.

    Snow driving is actually fairly impressive given the design and all season nature. In comparison to the other tires I have owned, these are by far the best. But the praise ends there. The Prius is an awful car in the snow and really needs snow tires. My Neon has been using Pirelli's for years now, and never needs snow tires, and I have even lost to my wife when racing up a steep hill. In fact, in winter she prefers driving the Neon in snowy weather as she says it feels safer than Prius with snows on, go figure!

    Otherwise, my only issue is with noise. The tires are quite noisy as they age, not sure if its the compound used, as all my tires were quite good and fairly quiet even as they aged.

    Overall, these are excellent tires, and I will be buying them again as they are such a great deal for the price. I got 4 brand new tires for $69 each, what an awesome deal for such high mileage, fuel efficient and good handling tires.
     
    #7 mlibanio, Oct 21, 2010
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