Sweet spot

This truck is geared extreme slow for fuel mileage. 58-62 mph is going to be the optimum road speed for fuel mileage.

 

from what I can gather, you'd be in that sweet spot.

For me, I'd pass because the driveline isn't rated for the torque I'd want to run.

 

If anyone want a copy, I built a small spreadsheet a while back that you can plug in tire revolutions per mile, final ratio out of transmission, and rear end ratio. It will give you road speeds from 1200-1600 rpm. It has multiple columns so you can put in the final transmission ratios from multiple gears to compare side by side and not just get information one at a time. It uses standard formula for calculation that RoadRanger or most any other online site uses.

Send me a PM with your email and I will forward you a copy. I have it in MS Excel or Open Office formats. Probably could save it as a copy in most any other format as well.

 

The Series 60 Detroit does really well in the 1400-1500 band for a balance of mpg and performance. with 3.7 rears and 11R22.5 rubber, in the top hole (usually .73 final), the road speed at 1400 would be right around 62 mph. At 1500, it would be right around 67. At 1300 it would be right around 58. Not a bad range for the Series 60 and a balance of road speed, mpg, and performance.

 

Well, the right driver can overcome any limitations in the driveline torque rating. There are many truck pull competition drivers that are running less than 1850 lb drive lines yet the engines are putting down 2400+ torque and they are not blowing out drivelines. Even the stronger drivelines in the hands of a bad driver will fail.

 

Seen many a drive shaft twisted up tight in a dump w/ a two-stroke diesel in it