Good tool but lacking some basic things that would take it from good to great. There’s no way to reorganize your list, which would be really nice to group models together with different gear and tire setups. I’d really love to see a master car list with a sub-list of available gear, tire, and battery options. As a quick and dirty tool, this gets it done.

I'm only giving it 3 stars because I tricked it to work. Need a way to set differential gear ratio. I tried calculating speed of new xmaxx. Found several calculators that work great online and figured I'd try the app. The only way I managed to get the app to produce close to accurate speeds was to set cell voltage to 3.75 and cells on 2. I'm appalled that I paid for an app that isn't actually accurate when it's marketed as a calculator.

It doesn’t state what size can the motor is or what type of pitch the gears have and there is no way to change it. It doesn’t even say what the can size is that the entire app is based off of. If they would fix this it might be worth something but I guess.?

Very few options . This would be okay if you was trying to get the general idea on how fast your setup is. But nothing 4 wheel drive . Nothing for the front and rear differential gears radios nothing if for car has Multiple gears. Just basic and waste of a dollar. So now I have keep it cause spend money on it . So it going as back ground on my phone so I would have to Search to use it cause that’s how useless this app is .