Help choosing gear ratio X15 605hp 18 speed

3.36 is good for an 18 speed
If you drop to the old 3.08 (bull hauler gear) it’ll drop your rpm to at 70 to around 1300ish but you’ll be splitting more.
I’d say 3.36 will do a good job.

 

Yep or stay with 55

 

Do you do a lot of tall stuff? If not worried about height I’d go with an 11 22.5 and 3.36, better ride and a little longer life out of the tire with the usually heavier loads

 

Tormoz: Not entering the rear gear question. My opinion differs from most.
Only saying congrats on the new ride. Have a friend, he is very happy with his 990!
Best wishes

 

@JonJon78

 

We run 88K in the PNW with a 505 Paccar and 325s. It is working very well. If you drive more miles in ID, NV, UT, MT and WY, I’d go with the 3.25’s. If mostly OR and WA, 3.36.

 

I have a 565/2050 X15, 18 speed with 3.25 rears on 24.5 lo pro. I’m right under 1400 at 70 mph and on flat or slightly rolling ground it is fine. The few times I’ve wandered into big hill territory it still did fine as long as I kept it above 1400 rpm. Hills that I would pull at 40-45 in my NXS Acert 475 the X15 would knock down a hill at 5-10 mph faster and a gear higher. 475 Acert had an 18 and 3.36s on lo pro 24.5 for comparison.

My next truck I’m spec’ing another 565/2050 with an 18 but I’ll probably cut back to 3.36 or 3.42 on lo pro 24.5. Current ride is long legged and I have to constantly slow myself down.

I’m loaded to 80k for nearly 2/3 of my miles, empty the rest and I average 5.5 mpg running the snot out of it. I do not baby it. Absolutely zero emissions or engine issues thus far.

A 605/2050 in that part of the country would probably be fine with 3.25 on 22.5 tall or lo if you’re staying at 80k and under. If you want 24.5 though I’d bump to 3.36 or 3.42.