Quote:
Originally Posted by wamey
Update, ran out with GPS, looks like speedo is 2mph higher than true speed.
70 Flat
72 Downhill
65 Uphill
75 Downhill drafting a truck 
Sorry it took me so long to get this, I had swapped back to the knobbies for a trip! |
So if anybody is curious about the gearing with the road tires listed here, just like my 120/80-18 Shinko 705's, a 110/90-18 with a 43 tooth sprocket is close to the same final drive ratio as a stock 110/100-18 with a 45 tooth sprocket thanks to the shorter diameter of the road tire.
You could toss a 41 tooth sprocket on the rear wheel with the BT45's and be geared just like a stock tire would be with a 43 sprocket. In fact, it gives 5th gear an almost direct correlation between MPH and RPM. so 40mph is 4000rpm, 50 is 5000, 60 is 6000. etc.