Need axle ratio advice/New 2018 389 505hp X15 18 spd 3.21 ??

Hell Survivor · Dec 29, 2020

Canucklehead said: ↑

I'm a little late, but gross up here for a tridem is 102,400 lbs.

Hope I made your day giving you the extra room.

I'm picking up my new used ride later this week. ISX 565, 3.55 ratio, 18 speed. Yes it will do fine in the mountains and the flat.

I'm living proof that low ratio can work. My last truck had 700 hp, 2250 torque, 18 speed, 22.5 tires, and a 3.21 ratio. Could out pull a Cat, and fly on the flat. I speant most of my time running Vancouver to Alberta, so I was mainly mountains all day. I still averaged 6.3 mpg pulling maxed tridems.
Click to expand...

I need help with my truck!!!!
I have got a 2016 Peterbilt 389 with Cummins isx15 550 horsepower 2050 torque 18 speed. Currently I have 3.73 rears (super 40).
Fuel mileage sucks on this thing I never get anything above 5.5 MPG even though I am pulling tandem dryvans and Reefers. Route is same as yours.
I am double-minded here whether I should go for 3.36 or lower axle ratio or should I keep the ones I have
any expert advice on this would be really appreciated as I have been driving only for 3 years and don't know that much about trucks.
Thanks
Have a happy new year

ravisidhu05 · Oct 14, 2021

3.36 or3.42 mt14x rear are best for vans and reffers or owner spec you can choose 3.55

Log in or Sign up

Forums

Find Trucking Jobs

Need axle ratio advice/New 2018 389 505hp X15 18 spd 3.21 ??

Hell Survivor Bobtail Member

ravisidhu05 Bobtail Member

Trucking Jobs in 30 seconds

Wait, employers can't reach you!

Log in or Sign up

Useful Searches

Find Trucking Jobs

Need axle ratio advice/New 2018 389 505hp X15 18 spd 3.21 ??

Hell Survivor Bobtail Member

ravisidhu05 Bobtail Member

Wait, employers can't reach you!