Towing and Overdrive

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Comments

  • warfishwarfish Member Posts: 117
    My new tires are load range E, rated for 3045 lbs at 80 lbs pressure, almost the same as the Michelins were. I also just had the rear end lowered and softened at a spring shop and now it's just great.
    obyone: Sorry for the confusion. The tires came with the truck from Dodge so I don't think they were Sears cheapos.
  • markbuckmarkbuck Member Posts: 1,021
    C range = 6ply 50psi
    D range = 8ply 65psi
    E range = 10ply 80psi
  • rrichfrrichf Member Posts: 211
    warfish,
    Now I understand what you're saying about RPM and REAL MPH. The tires are bigger and therefore it takes less engine revolutions to go a mile. Makes perfect sense, but alas the speedometer reads 'slow' for your real speed.
    Rich
  • warfishwarfish Member Posts: 117
    rrichf,
    Right, except I went the other way, to smaller tires. That makes my speedo read about 2.5 mph fast and I think there is enough variation in a normal speedo to make this not worth worrying about.
  • bob332bob332 Member Posts: 137
    Keep posting and this towing topic should continue. I like and prefer bigger tires--no big deal with the speedometer--just keep in mind that you have done it and allow for the difference. Problem might be when someone else drives the truck. The Silverado tow/haul mode will be better for a lot of jobs and especially for towing a fifth wheel. Bob
  • mahimahimahimahi Member Posts: 497
    The formula for the difference in the Speedo is: (New Tire Diameter/Original Tire Diameter)X Indicated Speed = Actual Speed with NEW Tires.

    Example: (32.5"/27") X 55MPH = 66.2MPH

    Here's the formula for the change in highway performance:

    (Original Tire Diameter/ New Tire Diameter) X RPM@MPH = New RPM @ Actual MPH

    Example: (27"/32.5")X 2400RPM = 1985RPM 55MPH with the NEW tires

    I got these from Tire Rack
  • meredithmeredith Member Posts: 575
    After 30 or more days of inactivity....

    this topic is being "frozen." It will be archived or deleted in the next 10 days or so.

    Front Porch Philosopher
    SUV, Pickups, & Aftermarket and Accessories Host
This discussion has been closed.

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