speedo drive gears

Posted by Gary49eight On 2022/9/1 10:50:20

Hello all.
Does anyone know how many teeth on the speedo cable drive gear should have for relevant diff ratios?
My 49 has a 3.9 diff and 19 tooth gear, speedo works fine and is quite accurate. I found a 17 tooth gear in my hoard, what diff would this suit?
Cheers,
Gary