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duct tape & zip ties
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I think you mean RPM's Revolutions Per Minute. At 70 mph my truck rpm's according to the stock tachometer is 2,000 rpm's.

This is with 3.73 gears, with a 4rR100 transmission. So for your truck it maybe different.
 

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let me look it up, BRB with a number for you.
 

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i just ran it and it came up with 614 revs per mile. you can check it yourself with this calculator. Tire calculator
 

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duct tape & zip ties
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Oh I am sorry you meant tire revolutions per mile. Yeah that is 633.5 according to the one calculator I used which is the same as that which has been posted already.
 

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hang on let me do it again.
 

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still showing 614 revs per mile. dont know what to tell ya. i tried that other calculator and it shows what that other member said, but so you know, the one i used was recommended to me when they sold me my SCT and it is what i used when i had my tunes written. go with who ever you choose.
 

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It shouldn't. That's just to "fine tune" the shift points. You don't really need to enter additional parameters, just so you know...
 

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I agree with the 614, i calculated it by hand, both calculators said the circumference was 103.1" so u figure 5280 feet per mile so thats 63360" so 63360/103.1 = 614.54 so i would say that 615 would be fine, especially if you figure tread wear will only increase that number.
 

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no i dont think it would hurt anything. i didnt have to program anything into it myself though. DJ's needed the number that i had for mine, so i dont know what increments they went in.
 
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