Originally Posted By John_Kunkel
Originally Posted By lewtot184
how did someone figure .67 ratio reducer? what pinion are you using now? i don't think the math is right.


Small tires and high (numeric) axle ratios generate speedo cable speeds that can't be corrected with the available 16-21 tooth early pinions. The .67 reduction allows the user to alter the normal math to choose the correct pinion.

As I stated earlier, the OP's combo would require a 23-tooth pinion which was never available so the .67 reduction would call for a 15-tooth pinion which, also, was never available; so a 16-tooth would be the closest.

That's why an inline reducer is more practical, they allow for a wide variety of reduction ratios.
john, i'm very familiar with the ratio reducers. i use one in my '65 coronet. it just seems to me that .67 is very steep, even with a 16 or 17 tooth pinion.