Thoughts on Proper gear ratio

Seems a 11r24.5 is 2 inches taller than an 11r22.5.
How is that no difference in tire height.?

Sure, the sidewalls are the same size, but the overall diameter is 2" different..

 

This is myth IMO.
I run a '92 DDEC II Series 60, 4.10's, at 55,000lbs gross & under. I've had IFTA quarterlys as high as 9.2mpg. Keeping boost psi low is what will help on the mpg side..

 

Few post back I did give you a screenshot of
lo-pro 22.5 (40" tall) with 3.58 vs
Tall rubber (43" tall) 24.5 w/3.91.
The difference was .8 miles per hour at 1500rpm in direct 1:1 gear, with the 3.91 being the choice that was .8mph slower, or slightly more power to the ground..

I don't know this fella, @uncleal13 We've never had a conversation before. Trying to tag him in, as I believe from reading his posts he runs a similar setup to what you are looking at. Cascadia w/Detroit power, pulling super B's. Maybe he will see this, & put in his experience..

Either way, congrats on acquiring a new ride.! I'm sure it will get the job done for you..

 

Still geared TOO low. 3.08 is the better of the ratios. Many 2.47 and 2.64 do just fine, just maybe use a gear lower in a hard pull. Good luck with your new truck.

 

You are grossing 140,000lbs with 3.08's..?

 

10-4 Yeah, I got you.

I was replying to this fella recommending 3.08's, or even 2.xx whatevers. I was asking if he was running heavy like you with that kind of gearing.. LoL

 

That setup with 3.42 and 3.58 is common on the prairies for us pulling Super-B.
Remember the DT 12 has a 0.78 final gear vs 0.73 for an 18 SPD.
For the mountains you may want 3.70 with that transmission.

 

1510 rpm at 65 mph. Probably pull fine with 3.58 and 22.5