Nor-Cal Hobbies “Gears” app is an R/C car and truck gear ratio and rollout calculator. Enter the transmission ratio, spur, and pinion to generate a table of gear ratios. Enter the tire diameter to get a table of rollouts. Designed for the R/C car or truck racing nut looking for a super easy way to determine gearing on your Android phone right at your pit table. It’ll run on phones with Android OS 2.0 and newer. And it is FREE!Brought to you by Nor-Cal Hobbies: http://www.norcal-hobbies.com