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2002 Prius tire pressure recommendation?

Discussion in 'Generation 1 Prius Discussion' started by War_Destroyer, Aug 24, 2022.

  1. War_Destroyer

    War_Destroyer Junior Member

    Joined:
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    Location:
    Los Angeles
    Vehicle:
    2002 Prius
    Model:
    ----USA----
    Hey guys, I bought the car in October for around $4000 with 61000 confirmed miles. Very well taken cared for with all the service records and receipts.

    It's the first summer with the car and yesterday I headed up to the university with my three bros, and between us were probably pushing 1000 pounds in weight.

    Anyway, the car ride was pretty bouncy, and the body would hit the campus speed bumps even if we tried to crawl over them from one side very slowly lol

    I checked the tire pressures first thing this morning, and probably the first time ever, and all four tire pressures were at 24.5 PSI. Ambient temperature was 73 Fahrenheit.

    The tires were new when I bought the car, and I've done around 4300 miles in them since buying the car.

    That's definitely lower than the "recommended" 35 PSI Front, 33 PSI Rear.

    I filled them up to the recommended, but I've seen old forum posts recommending quite a bit higher than that.

    What do you guys recommend these days?

    Keep in mind daily temperatures right here in Southern California for me are 100+ degree highs, 70 degree lows daily.

    Three times a week I for sure carry around a 1000 pounds, other days half or less.

    Here's a pic of the tires I currently have, don't think they're good, but are newish at least.

    20220824_090222.jpg
     
    #1 War_Destroyer, Aug 24, 2022
  2. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
    2010 Prius
    Model:
    IV
    When I first bought my Gen 1, I followed some enthusiast recommendations here and tried something 42 front 40 rear. I backed that down to 38/36 after it nearly jarred my fillings out and filled the dash and cabin with new squeaks and rattles. But the newly-created squeaks and rattles never went away even after backing the pressure down, so my first drive home from Schererville where I had bought the car was the quietest drive it ever made while I owned it (even though it had already driven 125,000 miles at that point).
     
    #2 ChapmanF, Aug 24, 2022
    War_Destroyer likes this.
  3. War_Destroyer

    War_Destroyer Junior Member

    Joined:
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    Location:
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    Vehicle:
    2002 Prius
    Model:
    ----USA----
    For sure 24.5 PSI on all four tires is bad right, that's a huge difference from the recommended 35 and 33 PSI. Yeah, there are some rough areas I drive through daily. You can hear all debris that gets flung around the rear wheel wells, but the only rattle I have is a little one in the third brake light when I drive through there.

    Are you still using 38/36, and is it that much better than 35/33?

    Do you think I should make all tires the same tire pressure? It's legit 500+ pounds in the back seats when I take these guys with me to school. I still probably won't clear the speed bumps, but going from 24.5 to 35 PSI is a good 43% increase lol
     
    #3 War_Destroyer, Aug 24, 2022
  4. Trombone

    Trombone Member

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    Location:
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    Vehicle:
    2002 Prius
    Model:
    N/A
    Many of us old timer original owners inflate(d) to the maximum on the sidewall. In my case (2002 Classic) the General Altimax get 44 psi front/42 psi rear---better for gas mileage. The ride is firm but not jarring. OEM tires were XL (extra load), but there's really no need for them, even if you could find equivalents today.
     
    #4 Trombone, Aug 24, 2022
  5. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
    2010 Prius
    Model:
    IV
    I am still using 38/36 out of habit (in my Gen 3 now, don't have the Gen 1 anymore), but as to whether it's actually better than stock, I can't really say. It is definitely less harsh than the higher pressures I once tried, and seems less likely to make new cabin and dash rattles and squeaks. (Unfortunately, I never got to test that in my Gen 1, because it was never possible to undo the rattles and squeaks that the 42/40 test created.)

    Pressure below stock is definitely not good.

    One does have to think carefully about pressures and load capacities with Gen 1 especially, where the small tires leave little room for error. I've remembered an old thread where I worked through the details.

    That link goes to a post in the middle of the thread showing the work for P-metric tires (the kind with a tire size that starts with P). The following post compares the details for Euro-metric tires (the kind without a P in front of the size). The rating systems and rules are very different.

    Unfortunately, PriusChat goes through software changes every now and then where the content all gets copied over, but the right way of doing table markup changes, so the tables in those old posts look bad now.
     
    #5 ChapmanF, Aug 24, 2022
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