250W 350W 500W Brushless Gear Front Rear Hub Motor for MTB E-bike Conversion Kit

Re: The rear hub motor fits the bike with a rear drop outsize “of 135mm”, The front hub motor fits the bike with a front drop outsize “of 100mm”. How do I know if this hub drive motor fits my bike?. When the hub motor is running, the current is relatively uniform, and it relies on electromagnetic induction to operate, with low noise and low wear.