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

It’s been explained. The stress of the side loading is not good for the pinion. The heavy weights with low rpms is not good for the u joints. I doubt you can get this set up in anything other than 40k rears if you can even get them in that. Start ability will be an issue, but may not be a problem in your operation. Grade ability will be a big problem. Everyone want to quote how well and compare pulling in top gear. Climbing a hill you will be farther into the gear box trying to make the top of a hill. If it is a long enough/steep enough grade you will run out of gears. Then what? The fuel you save on the level you will loose in the hills. You will be working the engine much harder this burning more fuel. At a certain point your gearing gets so high, economy starts going the other way

 

Don’t know why I bothered to type mine out.

 

Go back and read post #21. That 2.64 will have a lot of torque on it starting. That's why people are saying you'll be broke down all the time, shearing the pinion shaft. I think a 3.55 or lower gear would be quite a bit stronger. Will Freightliner even spec a heavy haul truck with the 2.64?

 

100,000 miles doing heavy haul? Let me hold a dollar...

 

If you have a direct drive trans and a higher gear rear, your top speed RPM will be near the same as if you went with a OD trans and lower gear rear. The final ratio is near the same, so I really don’t understand the difference.

I know who KR is, but I’ve never really listened to him. If you are getting your info from him, you need to stop. Think about it, if he knows all these ways to get rich in trucking, he’d own a trucking company intead of just talking about all the ways other people are doing it wrong. It’s my understanding that most of the stuff he pushes is just whatever his sponsors tell him to push.

 

Think of when tightening a bolt to 100 lbs torque is it better to use a 15 inch tongue wrench or a 24 inch? While they both get the job done the 15 takes a lot more effort with less movement and the 24 takes less effort while moving a little more
If you tighten 1 bolt it don't matter much but if you do 100 a day you will be a lot more tired at the end of the day.
The same thing with a truck yes you may do the same work but if you work it harder you put more strain on all components instead of lighter work but a little more movement.
The strain will show on every component from the fan to the tire contact patch.

 

You have to be able to get into direct and stay there. That is where I think you will struggle.