Hey everyone how ya doing, I just bought a sportster a couple of weeks ago. It has a 21" front wheel and no speedometer, the speedo drive is there on the right side of the front wheel. I have done some research and found that the sporster uses a 2:1 ratio speedo and speedo drive unit with the 19" front tire. My question which combination should I use with the 21" front wheel? The drive unit rotates 2.5 times to one full revolution of the front tire. This is roughly a 25% difference which I believe will not be constant across all speed differences. Please help me

Mike