Intro & question on Speedo revolutions/mile

Unknown

Hi,

I have a 1940ish Hudsonish Truckish contraption. The cab and frame less the front clip are 1940 Hudson pickup. I'm sure I'll give more details in the rods forum, but I have a stock Hudson question.



I am getting my speedometer gears in order for a trans swap. I am using the suggested calculator at http://www.bgsoflex.com/speedo1.html.



There is an assumption that the Speedo turns 1000 times every mile, but this is not the case for all older speedos. My question is how many turns per mile do Hudson speedometers make? My speedo is orignal to the 1940 pickup cab and says "Hudson 112" on the face (does this mean 1120 revs/mile or is this meaningless??). Thanks in advance.

Park_W

Hudson 112 was a model name. 112" was the wheelbase for that series.

The older speedo's turn exactly twice as fast as the later ones. They changed in '50 or '51.

Unknown

Park W wrote:

The older speedo's turn exactly twice as fast as the later ones. They changed in '50 or '51.

Thank you for the quick response. Does that mean 2000 turns/mile on earlier speedos?



Thank you.

Park_W

I don't recall the exact figure, but any speedometer shop can tell you. It was an industry standard.

hudsontech

There are instructions, in several of the Mechanical Specification sheets on how to figure speed and/or RPM.



Go to http://www.hudsonterraplane.com/tech/tech_index.htm and click on, for example, 1931 Essex Super Six Mechanical Specifications. Tho later years didn't carry this information they can be used for most any year simply by plugging in figures from whatever.



Hudsonly,

Alex Burr

HudsonTech

Memphis, TN