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.
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
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.
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
Comments
obyone: Sorry for the confusion. The tires came with the truck from Dodge so I don't think they were Sears cheapos.
D range = 8ply 65psi
E range = 10ply 80psi
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
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.
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
this topic is being "frozen." It will be archived or deleted in the next 10 days or so.
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