Axle Ratios

[Suzuki6mx]

Starting to look at new trucks, chances are ill order a new one. What have you guys found is the best axle ratio on a f350 CC LB? Ill be pulling my camper on the weekends and some machinery during the week. Thanks

[poormanscat]

old school thinking here... if you are getting any truck to work, get all the gear you can get.. my goat has 4:10 and could pull the world out of orbit if there was a place to hook a chain.
I would steer clear of the 3:31 geared trucks... may be great for fuel efficiency when unloaded, but if you need maximum pulling power, they will not be your friend.

[1tough_crew]

I pull a 30 travel trailer, and it takes a fairly significant grade for it to downshift while using cruise control. I'm not a heavy hauler by any stretch, but I'm very happy with the performance (and mileage) over the first 30k miles.

[BIG Laing]

I have the 3.55's on my CCLB, And for what I do its perfect. Great MPG empty, and still has a max tow rating of 15,000 Lbs. It pulls 12,000 so easy it's amazing.

If I were to get a bigger toyhauler (33 ft+) I am sure I would want 3.73's.

IMHO

3.31- not if you tow alot. Great if you commute in it.

3.55- if you ocasionally tow around 12K

3.73- if you pull around 15K quite a bit

4.10- (dually only?) Big Boys.

[jcatchem]

I pull 17k all the time never dropped below 5th gear up any hill running 3.55. The most i would go would be 3.73 and that would only be to get the larger axle shafts.

[mach14604]

I love 3.55 axle ratios. I have it in my mach1 from the factory and now have it in my new 2012 CCSB F-250. I like it because of the RPM the engine is running at goes down the highway at 65mph. I pull a open landscape trailer and enclosed 20ft car hauler. I had a 4.10 in my 2008 F-250 SCLB with a V-10 and hated the fact that it was running at at over 2000rpm when going 65-70mph. To me 3.73 was still too high and the 3.55 is perfect.

[BIG Laing]

Originally Posted by jcatchem

I pull 17k all the time never dropped below 5th gear up any hill running 3.55. The most i would go would be 3.73 and that would only be to get the larger axle shafts.

I personally wouldn't tow over what the truck is rated for "all the time", once in a while it is almost inevitible. I know they can, but in my mind that is extra wear and tear that I don't want to put on my truck.

[dslbrnr]

I have 3.31 and running around 1600 RPM at 70 MPH with stock 18's. From what I hear guys with 3.55 running stock 20's are turning about the same RPM at 70 as well. Both gears are rated the same for max towing aren't they?

[BIG Laing]

Originally Posted by dslbrnr

I have 3.31 and running around 1600 RPM at 70 MPH with stock 18's. From what I hear guys with 3.55 running stock 20's are turning about the same RPM at 70 as well. Both gears are rated the same for max towing aren't they?

Yes

Here is the math, as to why they rev the same.
34.8x3.14=109.3/3.55= 30.79" traveled per driveshaft rev
32.8x3.14=102.99/3.31= 31.11" traveled per driveshaft rev
They are pretty darn close!

I am bored.
32.8x3.14=102.99/4.10= 25.1"
32.8x3.14=102.99/3.73= 27.6"
32.8x3.14=102.99/3.55= 29.0"

[dslbrnr]

Big Laing I figued you would have this down to a T.
When I was shopping for a truck I really wanted the 3.55 gears, because I always ordered my trucks with either 3.73 or 4.10's. The dealer I puchased from had very few 3.55's so I ended up with 3.31's. Like everyone says 1st gear is much lower on take off so I really don't notice much difference from other trucks I've owned with lower gears. Now that i'm older (52) I really won't be lifting, well maybe a level kit but not to much taller tire.

I haven't towed much weight yet but from what I have, I doubt i'll have any problem. These trucks have plenty of power and so far i'm very happy