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Discussion Starter #1
My truck came stock with 3.42's and i have massive 285/50R20's on and im thinkin about changing the gears instead of a smaller tire. after my new goodyears are gone ill probably go down to a 275/45. would 4.10 give me too much bottom or would they be just right? BTW its a 2002 RCSB 4.8
 

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IMO 4.10s would be just right for both of those tires if you want the truck to be quick. if you want economy, keep the gears you have, believe me, its still a lot better than my gearing, and my trucks heavier...nooooo fun. If you regear, i wouldn't want to go much smaller than 275/45s...i just don't see the point in goin from 3.42s to 3.73s...
 

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Discussion Starter #4
I'm used to my '96 lifted with 35's and 4.88, gotta love that low end, i'll probbaly just go with 4.10's in my new truck, especially sense my 285/50's are bigger than 31's....i look at it in a way that i will be saving my tranny from some stress
 

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Discussion Starter #8
I think i should just get 4.10, the tires i got on now are bigger than stock 4x4's, i guess my main issue is that my next set of tires will be 275/45R20 which are like an inch and a half smaller than my 285/50R20. will 4.10 be too low when i get new tires?
 

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This page should give you some info about what RPM's will give you what speed.

This excel spreadsheet works well too, it gives you the speeds through the RPM range in all gears.

http://www.free-online-calculator.com/recreation_calculators/car_calculators/road_speed_calculator/road_speed_calculator.shtml

Example....
(I did the overdrive ratio of a 4l60E .696 OD ratio, found here decimal point is misprinted on webpage)
Input Parameters Are the Following:

* Differential Gear = 4.10 to 1
* Transmission Gear = 0.70 to 1
* Tire Diameter (Inches) = 31.00
* Engine RPM = 2000

Computation Results:
# Computed Vehicle MPH is 65
 

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Discussion Starter #12
yah i found the 4l60e ratios, 3.06 1.75 1 and .7, i found my diameter too, 285/50R20's are about 31.2, everything looks pretty damn accurate, thanks for the link
 
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