Final Drive Ratio

[the hamiltons]

Arch,

We're just starting the third season with a 3.70:1 final drive ratio from
seven years with the 3.07. Each year's average has hovered closely on both
sides of 9 mpg with both ratios. I drive 60 to 65 mph and still have the
original 455 engine with 96000 miles and 8.75x16.5 tires. I have added items
that increase wind resistance in the last three years such as awnings and a
sunvisor. The weight of the coach has gone up by about 300 lbs from adding
so many things.

I think if the coach was still as we bought it in 1991 the 3.70 final
drive ratio would give a small increase in mileage along with the great
increase in performance and joy of driving. The diffence in performance is
in the 40 mph on up. It is without doubt the best change we made to the
coach.

Al Hamilton
76 Eleganza II
Kingston, Ont

 

[phil swanson]

Hello,
I had the final drive cover off my 77PB and decided to count the
teeth on the ring and pinion to see if anyone may have changed the
ratio. To my surprise, I counted 41 on the ring and 15 on the pinion.
That would mean that I have a ratio of 2.73 to 1!! Has anyone heard of
higher gears than the 3.07 that was stock. I thought everone was going
to lower gears for the obvious torque gain.
The stock gears are 14 and 43 at 3.07. The Cinnabar ring gear is
41 like mine but their pinion is 12. I can't figure out where my 15
tooth pinion came from and why anyone would build a higher ratio than
the stock 3.07.
Has anyone ever seen a final drive with higher gears (lower
numerically) than stock before and has anyone ever heard of a 15 tooth
pinion for these units?
Looks like I am going to have an overdrive without even trying.

Phil Swanson
77 PB