For those of you who want to build an electric bike/minibike this Excel spreadsheet (w/graphs) I made might be useful in estimating your max speed. I did all of my research using "Build Your Own Electric Vehicle." It is only for a single gear though and you'll probably have to do some editing in the 'MOTOR SPECS' area if you want to use it. The biggest problem I had in putting this chart together is that none of the smaller sized scooter motors I've found online include torque curves, so I went off of these equations I found about calculating RPM decrease due to rising current.