Packard Forum Index » Post-War (1946-54)

I was browing through the specification section in the '54 Service Manual, and noticed something about the Rear ratios on the '54 models. Why does the Clipper Deluxe Chassis use a of 3.23, anf most of the other Chassis use a of 3.54 for the Ultramatic? (see attached pic)

Attach file:

---

  (85.85 KB)

lower end model...they do that nowadays. my ford ranger edge had 4.10 rear gears....while the others were not.

The 5400 had a 288 so a little lower axle ratio accommodated lower power output. The clipper deluxe had a 327, but ran the smaller 7.60-15 tires. It has the power and torque to maintain a higher cruise speed at a lower rpm. It appears they made up the difference with taller gears in this model. The other cars listed seem to run 8.00-15 tires and are equipped with a 327, therefore run a lower axle ratio giving nearly the same rpm / mph relationship.

There is roughly a 10% difference in the gearing between the two ratios, and I am guessing about the same difference between the 7.60-15 and 8.00-15 tires in rolling circumference.

This is just a stab in the dark, but hey, even a blind bird gets a worm once in a while.

Jim

i like your answer better LOL!!!

I think the reason is likely entirely promotional, that it was very important to Packard that the Clipper not outperform the premium Packards so they geared it such that it didn't have either gearing or power to overcome the wind resistance at higher speed and thus had a lower top speed. Of course acceleration would also be slower, due both to the gearing and horsepower/torque.

I do find it odd that they did not apply the 3.23 ratio to the 288 Clipper "Specials" which were the lowest end Clippers offered, only 327 Clippers. You would have thought that they would have offered the same ratio across the Clipper line.

A light car with a big high torque engine can spin the higher gear. The same car with a smaller engine can't. Likewise, the same engine in a heavy car has no power to spare and needs the help of lower gearing.

The Clipper Deluxe would have more relaxed high speed cruising and a tad better mileage thanks to the higher gearing.

It's really a matter of weight and how much power you have to move it. I bet you find the standard Clipper and the heavy models have about the same power to weight ratio while the Clipper Deluxe has more horsepower and more torque per pound of weight.