gear ratio/rpm

[gophergunner]

just curious what kind of rpm i can be expecting my engine to run at say 60 or 70 mph. right now its an '89 blazer with a 6.2, 700R4, 4x4, and the axles i'm putting on it have 4.10 gears. Tires on it right now are 245/75/16 but i would also like to know what the difference in rpm would be for some 33" tires or 35" tires as well.....anyone know this stuff?

thanks

[john8662]

Check out this link with a calculator on it for RPM with different gears etc.

Gear/RPM Calculator (http://www.700r4.com/speedoCalc/rpmcalc.shtml)

Input different numbers and see what you get.

J

[gophergunner]

thats an awesome tool.........thanks a bunch

[Robyn]

My 91 Burb 1/2 ton has 3.42 butt gears with 35 inch tires.
Bloody well kills the poor little 6.2 on the hills
4.10 would be great with the 45 inchers and the 3.73 would rock with 33 inchers.

The little 6.2's love to run at about 2500 on the highway and will happily do so all day long day in day out.
If you drop the RPMs down to around to 2000 its seems to knock the MPG down some.
The little engines definately have a sweet spot.

At Highway speeds the engine noise can get a little old after a while BUTT.

My old 86 Burb 2500 had stock 16 inch tires with 4.10 gears and would run down the road at 70 and get 22 MPG

Not bad for a rig that weighs 6500 pounds and has the aerodynamics of a brick.