10-Speed Peterbilt 379 - Save Fuel with 13-Speed Upgrade?

Lol that's what I was thinking too...... I guess he does not realize that the experience deal is joke usually

 

I agree with you for sure. I thought the truck I drive was going to be geared to high but once I started to drive it I think it is perfect. 3.36 gears with a 13 speed sitting on 22.5 low pros. If I owned it I would put 24.5s on it with low pros and see what it would do.

 

The truck I'm driving was ordered with 3:36's and 11R24.5's and was perfect. I have since switched to LP 24.5's and I'm not as happy with it. You wouldn't think you would notice the RPM difference but now it is turning a little fast in 12th and didn't have enough power to pull heavy loads in 13th (PDI reflash has since fixed the power issue) . Before the tire switch anything under 65mph you kept it in 12th and 65+ you ran 13th. Now I find myself in high gear a lot more.

 

No I didnt realize the wana be was a joke.

 

@ 65 I'm at 1350 in 13th , 1350 @ 55 in 12th and about 1475 @ 60 in 12th. I used to be closer to 1350 @60 in 12th so with the smaller tires I have a choice of 1475-1500 in 12th or 1250 in 13th which is too slow.

 

Have you ever hauled anything actually heavy in the mountains? I split the lower gears all the time when im going up a grade because a whole gear is to much of a jump. Usually in flat land i only split 4th before going up to 5.

 

Here's my issue, I specifically said "MOST" trucks with 18spd's never split the bottom gears. I know for a fact that I would have almost zero use for them and I'm limited to 120,000#. My truck with a 13spd and 3:36 gears will got a maximum of 20mph in low range. I have yet to see a time where I need to split gears between 0-20mph. If your off road and heavy fine, if there isn't much of a price difference, fine. But again MOST trucks have no need for the 18. The only way I could see the benefit is the slower reverse gear, other than that it's like a turn signal in a woman's car, useless.

 

Low low is also a lot lower than a 13 but very seldom will it be used. A 13s low is 12.31 to 1 an 18 is 14.40 to 1.

 

You mean the guy with 15k in a dry van on flat level asphalt probably won't have a need for a 14.40:1 low gear? That's why I laugh when I hear guys wanting the 18spd. They're usually the same guys I hear talking to their buddies about being "heavy" with 42k in the box. And I have friends that routinely load 100k net on a flatbed with a 10spd.