[MetalMan]

41? What spur gear is that?

The way I like to set up my vehicles' gears before trying anything out is by achieving a speed I know I can get out of them (based on a speed calculator like BrianG's). For XL motors on ~4s-5s, I like to shoot for 40mph. For my Revo, this way of theoretical thinking worked perfectly, as my motor has yet to exceed 150 deg. In some cases, the real speed might be higher than the theoretical speed. Like, for example, my X-Terminator. A highway patrol guy clocked it at 42mph, but based on the numbers I put into the calculator (46/13, Feigao 9L, 5 cells @2.8v, 4.5" tires) I should be getting 39mph.