CUCV MPG thread

[MCK5]

I'm getting about 17.5 in my DD M1009, mostly highway @ 55-65mph.
14B & D44, 3.73 Gears, 31x10.5 tires.

Hoping to thow some bigger tires on soon to help with the gearing change.
RPM is a little higher than I would like when at highway speeds.

 

[mudman]

Hey MCK5..You're kidding right..About the RPM's at highway speeds and you have 3.73's installed now..What the?? You should be able to travel 100 miles an hour with that kinda gearing..Of course it leaves you to high a gearing for any reasonalbe off road use.

 

[Castle Bravo]

3.73 gears are lower than the stock 3.08 gears, so his M1009 should be slower than a regular M1009.

 

[MCK5]

Stock M1009 had 3.08 gears, the axles under it now are 3.73.
With the 3.73 gearing, 85mph puts me at about the 3,600 RPM redline.
65mph is putting me at about 2,800 RPM, not exactly helping fuel economy.
By my math, putting a set of 37" tall tires will get me back to, roughly, the same final gearing as I had with the stock setup.

Edit: ...that doesn't take into account the loss in MPG for putting on some BIG tires.

 

[TXM1009]

I have 3.08 gears and I won't drive over 65. I usually keep it between 55-60 when on the highway. I wouldn't go 65 with 3.73. I looking to go to 33s or 35s on mine.

 

[mudman]

I have 3:73's in a 90 suburban with stock tires and wheels, and a T-400 Trans. I live in a very mountainous area, pull boats to Tahoe. I wish I had 4:11's. With the stock gears I turning about 3,000 at 70 Mph. I have 4:56's in the 1028 and I love them, great for off roading to your favorite fishing hole. But then I'm never in a hurry to get any where either.!!!

 

[mudman]

or the loss of horse power to turn those bigger wheels and tires.!!