SkrapIron

Using your e-maxx example, yes, you would end up with a different gear ratio as the t4. The RPM of the motors ideally should run X number of revolutions for X inches of circumference of the overall wheel, but weight is a huge factor. Remember that the emaxx is using 32 pitch gears ( 66x18 ) and the transmission is 28.9:1 in first and 17.9:1 in second gear..... the E-maxx is geared WAY LOW ( -10.8359 ). Starting off in second (17.9:1) is closer to the 1 to 1 ratio (18.0641" circumference), but the truck is a dog! If you switch to smaller diameter tires ( such as Pro Line Road Rage ) you need to raise the spur gear to compensate for the smaller diameter tire. Divide your old tire diameter by your new tire diameter ( Ex 18.0641/17.278= 1.04549 ) and multiply that by the number of teeth in your original pinion ( Ex 1.04549x18= 18.8189) Rounding to the nearest whole number shows that you should raise the pinion 1 tooth to keep the same final drive ratio. Just try to keep as close to the starting value ( -10.8359 ) when selecting a new pinion or you will lose the torque required to get this rig rolling.

So to answer your question, yes. Weight is a factor when determining where to start out. Obviously, tipping the scale at over 9 pounds requires the motors to be OVERLY torquey, low RPM and geared WAY LOW. To gear the truck at a closer 1 to 1 ratio would require a motor that is 10 times as powerful as what is supplied but would require more batteries, and thus add more weight!