Gear ratio over drive or direct for heavy haul up to 110K?

If you really want to "boost your bottom line", get the 2.64s out of your head. You will end up spending way more on repairs than you hope to save on fuel.

 

Ok, when you hit “reply” type your message after the last line of the post you’re quoting right where the blue line is like this.

 

So you went 100,000 miles at 90-95k weight wise and you are worried about getting an extra mile a gallon.

Son, you bid that RGN work wayyyyyy to cheap then. If you're pinching pennies like this, its pretty obvious.

 

I’m not going to argue with you. You have made up your mind, be dammed what anyone else says. I don’t know why even ask for others opinions. I say do it then give us an honest analysis in six months. And a mpg is a mpg it will save the same. You meant to quote KR on a 10% increase. I heard him yesterday tell a guy to run a 2.18 and I’m not even sure they make that one. Anyways have fun busting a drive line.

 

It was explained, you just chose not to read or comprehend it.

A 2:64 gear versus a 4:10 (for example) has less teeth on the pinion gear. Which means, each tooth on the pinion gear has to take a larger bite thus severely increasing the amount of load of each tooth on the pinion gear. Creating a severe amount of torsional stress on the pinion gear and teeth, and anything in front of it (example: yokes, u-joints, driveshafts, transmission gearing, clutch etc)

Some gear ratios use the same amount of teeth on the ring gear, but change the number of teeth on the pinion gear to get the desired ratio. As @wore out already tried to explain to you but you basically ignored it, the pinion becomes larger and the number of teeth on it becomes less. When the pinion is larger and tooth count is reduced, it requires alot more energy to turn and the amount of stress becomes overwhelming....hence a sheared driveline, or differential.

Bottom line, it takes alot more torque and energy to move something heavy with a more direct drive approach. Always has, always will. There is a reason why heavy machinery mechanics almost always carry a torque multiplier in there toolbox or in the shop they work in.

Do you know what a torque multiplier is? Do you understand what it does?