How fast does the PostJoy S9 go?

PostJoy rates it at 28+ MPH top speed. That is above the 20 MPH limit many states set for street-legal e-bikes, so check your local rules before riding at full speed.

What is the real range on a charge?

The 55-mile figure is a maximum, reached with low pedal assist on flat ground. Expect noticeably less range at high assist or full throttle, and less again with a heavy rider or hills.

Is it good for off-road riding?

The 20 x 4.0-inch fat tires and front suspension suit gravel, beach, snow and light trails. It is not a mountain bike: there is no rear suspension and the fat tires add weight.

What does NFC unlock do?

It lets you unlock the bike by tapping a paired phone or NFC tag instead of using a key. It is a convenience feature, not a substitute for a good lock when parked.

PostJoy rates the bike IPX6, which covers strong water jets. That is good for rain and wet roads, but it does not mean you should submerge it or pressure-wash the motor and battery.

Riders who want speed, range and stability on mixed surfaces and don't need to carry the bike often. If you need something light for stairs or a small apartment, a lighter commuter e-bike fits better.