Posted by Clint Dixon on Friday, September 20, 2002 at 9:40PM :
In Reply to: Re: What are the tire diameters? posted by Fred Coldwell on Friday, September 20, 2002 at 12:46PM :
Hey Fred. Luckily I recorded all of that research information when I was trying to figure out speedometer correction by applying different combinations of the available speedometer ring and pinion drive gears!
The rolling radii of my half worn 9.00X16 nondirectionals, load range D, mounted on the correct 6.5X16 Budd Power-Wagon wheel, measured in at 16-5/8". The rolling radii of my half worn 8.25X20 Goodyear retreads, load range E, mounted on the wide Ford AA Budd wheels, when mounted on the same truck, measured in at 18-1/4". This equates to a 10% increase in rolling radii and road speed by using these tires and wheels over the 9.00X16 NDTs. You would gain about half as much of an increase in road speed at any given RPM by using this combination, compared to the 20% increase gained from changing the differential gears from 5.83:1 to 4.89:1.
The Ford collector, from who I eventually purchased this truck, had an early '30s Ford AA pickup truck. I believe it was rated at a ton or ton-and-half. Its wheels were much narrower. He said that he had switched wheels and tires between his Ford and the Power-Wagon at one time to see how the taller tires effected the drive in the Ford. Both sets of wheels had the same bolt pattern and center hole size. This leads me to believe that not all Budd wheels necessarily had the same center hole size, as some contend that the Dodge needs a larger hole than the Fords. Maybe vintage had something to do with it?
The Ford collector, who I spoke with last weekend, mentioned nothing about Ford wheels with wire spokes. It would stand to reason though, that maybe some of the early Ford wheels were of the wire spoke variety unless the truck was ordered specifically with the Budd disk wheel. As an additional note, by habit I refer to these wheels as "Ford AA". This may not be totally correct, as I do not know for sure just how long this model of truck was in production. I was just told that this bolt pattern was used on Fords into the late '40s.
My experiences with the quality and strength of these wheels has been just the opposite of what Ken relates below. Maybe mine were newer/thicker. They were, after all, wider than most I have seen. I do know the complete history of this particular truck. I know it was used as a daily driver, with these wheels, from the mid '50s until I bought it in 1993. During most of this time it was used to carry its owners dragline bucket and dozer blade on gravel roads. No cracks so far. Maybe dumb luck. Armed with this information, I would definately check any wheels very closely before purchasing.
I used to have six different formulas for figuring gearing, speed, and RPM based on rolling radii and overall diameter. Somehow this information was carefully filed in a place where I cannot readily find it. Time for a performance review for the file clerk!
Clint
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