I'm working on an electric car model and I need some help figuring out what I should set the gear ratio at it (it will be a fixed ratio that does not shift). I need to find what the options are on accelertion verses top speed. The motor being used maintains a steady torque of approx 670Nm from 0-1500 RPM, and then begins to drop off at a level rate to 100Nmm at 5000 RPM (top motor speed). The wheel diameter is approx 28 inches, (which I believe is about 88 inches in circumference). The vehicle weight is approx. 7000 lbs. Say that drag and friction are negligible (these are very loose approx. figures). How do I find acceleration and top speed of the vehicle? Mainly I need the acceleration on a level surface, so that I can figure out what the best gear ratio to set the car at. Mainly what I am asking for is an equation that would allow me to convert torque into acceleration given a vehicle weight. Thanks.