Put new gears and tires in/on my 92 Ranger. My stock speedo gear was: 17 teeth-green (C7SZ-A). I had 3.45 gears and 25.9" (215/70/14) tires and now it's 4.10 gears and 31" (31/10.5/15) tires. Without the tire change I did some calculating and I think I'll need the 20 teeth-orange (C8SZ-B) speedo gear. How would I factor the tire change in? Someone told me I should be okay with my stock speedo gear, that it wasn't off by much, but I'd like to be sure before I do long distance on-road driving.
Thanks.