got another6.5 tire size and gearing ?

[markmartin]

Hi guys, long time no see, I bought me another 6.5 after about a year of driving a gas 350 truck. Its a 94 3500 crew with single rear wheel. 2 wd with 95,000 on the odo. Here is my question, My old 94 with the same motor was geared lower 2000 rpm = about 65mph, this one 2000 rpm=55mph
the 3500 is geared more so for pulling I am assuming, CAN I put some taller tires on it and help this out a bit ? it has 245/75r on it now. What if I go with a 285/75r ( taller Iam sure) any input would be appreciated

Mark

[markmartin]

according to some research I found this:
typical mileage at 65mph - 3.08 gearing 1690rpm [23]- 3.42 gearing 1880rpm [21] - 3.83 gearing 2050rpm [17]-4.10 gearing 2250rpm [15]

I am thinking I have the 4:10 gears, Larger tires would help me out I think, dont you ?

Thanks

[Warren96]

When i went from the stock size 29",to taller 31"" size i couldnt see any difference in mileage,and i check the mileage religiously! Most members here feel the 3.42 ratio is just about optimum. A bigger tire wont get you there. Just my .02c

[gotdiesel]

If you go to a taller tire, make sure you recalibrate the speedo/odo, to get a
correct mpg calculation. A 29" tire will have about 710-715 rev/mile
and a 31" tire will only have about 675-680 rev/mile. It will have slight difference on the ODO.

Just a thought.

Greg

[TurboDiverArt]

If you go to a taller tire, make sure you recalibrate the speedo/odo, to get a
correct mpg calculation. A 29" tire will have about 710-715 rev/mile
and a 31" tire will only have about 675-680 rev/mile. It will have slight difference on the ODO.

Just a thought.

Greg
Without recalculating the speedo, just figure out the difference in tire size (eg. 4%). Then when you go to calculate mileage, take odometer mileage and multiple it by 1.04 (1+4%) and you have the actual mileage traveled. Then divide by fuel used for your actual MPG. My tires are 3.5% taller than stock. It calculated to a speedo error of about 2-3 MPH at 65 MPH.

Art.