[KennyBlanken]

You can't "easily" modify an electric brushless motor to go faster than its Kv limit, to handle more current than its magnetic saturation limit, or to exceed the limits of back-EMF.

99% of the people whinging about ebikes have no idea what they're talking about.

There are people claiming in this very thread that kids are modding their "e-bikes" to go "45mph."

The power levels required to push a hybrid bicycle to 45mph is north of 3000W and thus well beyond the capabilities of the motors and battery packs in nearly all electric bicycles. Even the e-motos struggle to hit those speeds; you need a pretty high end, expensive one to do so.

[namibj]

Well, you can switch from high efficiency to field weakening once you run out of supply voltage to handle full field back EMF as you increase speed.

That can readily double your speed on flat or downhill terrain if normal torque is sized to give good acceleration from standstill.