[brian_]

Okay, now we're in the right section, so I have removed my comment about location in the forum.

These motors include the hub and bearings, and have a non-rotating mounting shaft sticking out the "back" (inboard side). They are primarily intended for motorcycles or conversion of bicycles, which have a suspension arm designed to clamp onto a shaft like this. In a typical four-wheeled vehicle the existing "hub carrier" or "suspension upright" component would need to be replaced by something custom-built with an appropriately sized hole to accept that mounting shaft. The hub carrier must also have a bracket to hold the brake caliper, which must be positioned to fit with the brake disk, which is bolted to the inboard side of the rotating hub/motor case (and is shown in some photos of some models, but not this one).

I don't think any automotive designer would want a hub motor which is mounted this way, and no production car will be designed to accept it directly, but it can be accomodated.

 

[brian_]

Looks like you loose all ground clearance

In a simple beam axle such as shown in the photo linked above, the motor mounting shaft can't reasonably be in line with the beam. The beam can be below the motor shaft (as shown; this is called a drop-beam axle), or above the axle shaft (like a portal axle... not needed or suitable for a road car), or even ahead of or behind the axle shaft (but watch for torque due to the vehicle's weight trying to twist the beam on its spring mounts). The third-generation Honda Civic (for instance) had a rear beam axle with the beam behind and below the hub centres.

I wouldn't want to put all the effort into building a custom suspension and end up with leaf springs and beam axle, but for a very low-performance vehicle it is a cheap and easy way to go.

How do they mount the dual shaft versions?

On a traditional motorcycle front fork or two-sided rear swingarm.