gearchart.com /
 

how do you make a gearchart that shows the tire size with pinions instead of the fdr?

why would you want that? isnt it easier to change a pinion than to change tyre diameter?

I would use Excel and make one axis your FDR with different pinions, and your y axis different diameters.

This, of course, would be very useful for anyone running foam tires, where you can true the diameter that you want. I'll try and whip one up and attach it.

Twisted, what kind of chassis are you running and what size spur?

Hey, wait a second, gearchart.com can do that for you. Just fill in all the information (pick your car, spur gear, and pinion), make sure your "plot spur/pinion" selection is set to "middle", then below that put your average tire width (say 58 mm), and MAKE SURE to select "yes" for "Target rollout chart?" Hit the "Rollout" button and there you go.

rollout button.....