Pinion Gear Question for 1940 Champion

[reichsrundfunk]

Hi Guys,
OK here's where i show off just how numb my brain is: my 1940 Champion's speedometer reads low on speed vs actual driving speed. At 30MPH the speedo reads 25; at 60 it reads around 50-51, nearly 10mph off from true speed. Now here's the question: to make the speedometer run faster and thereby reflect true speed, do I need a pinion gear with MORE teeth than the current one, or LESS teeth than the current one? The present pinion gear has 14 teeth. Anyone know the answer to this one?

Thanks,
-George-
-63 GT Hawk
-63 Champ
-56 Golden Hawk
-51 Land Cruiser
-40 Champion Cruising Sedan

[Tom Bredehoft]

To make the speedometer read faster you need smaller tires, or more teeth on the speedometer drive gear. The latter is the easiest fix. Probably one more tooth.

[reichsrundfunk]

Thanks Tom. Interesting; my pinion gear has 14 teeth,when you look at Studebaker International's catalogue, it indicates 18 teeth The little voice in the back of my head (not the schizophrenic one, the other one...) tells me that 10 mph off at 60 MPH speed would require more than one tooth to compensate for, so I'm gonna guess at 18 and go with one of those. Maybe just to make myself feel more assured i'll get a 16 or 15 toother too.

The tires are 16" which is correct for that car.
Thanks!