Gear Ratios: Misinformation at its worst.

I pretty much read all the post, and if I we’re to need SOLID information, I’m relying on Hammer’s info. In his post, I feel a lot of confidence in his knowledge. I have no idea what the anatomy of the truck transmission internally is. But, again, if I have to spend the big money on one, Hammer would get my call.

 

Gearing doesn't make much difference in the speed you pull a hill either. At the end of the day the torque to the wheels is the same. With a taller rear ratio you just compensate for it with a deeper ratio in the transmission.

 

Myself I'd rather have a little more ooomph down low. I can imagine how hard a 2.XX ratio would be on everything if trying to get moving out of a hole when loaded. Just screams twisted driveshaft to me.

 

From my spec sheet, here are the ratios for a 12 speed Paccar transmission.

1st 14.4
2nd 11.0
3rd 8.44
4th 6.46
5th 4.95
6th 3.79
7th 2.91
8th 2.23
9th 1.71
10th 1.30
11th 1.00
12th .766

R1 16.92
R2 12.95

Not a direct drive like the topic here, but it is spec’d with 2.79 rears to down speed the engine to run in peak torque.

 

I have 2.62's and a direct drive FRF-15210b. 1st doesn't seem very low. Never looked at the speed at idle, but it doesn't "feel" low like a compound gear. For what it's worth, the truck idles at 5mph in 3rd gear, 10mph in 5th. And put on a seatbelt if you want to go backwards.

 

I always thought it would be hilarious to pull a roll-off trailer with campers on it with a two axle long nose Pete with a C16 under the hood. Obviously you'd need an 18 speed too just in case the turbo started to accidently spool on a hill.