It depends whether you're talking about an electric bike or an electric car. Adding a hub motor and batteries to a bike is a admixture of pro and con: you access the bicycle's weight absolutely appreciably but, in return, you get a affable and effortless ride whenever you don't feel like pedaling. Where electric cars are concerned, the allowances are added obvious. The weight of the metal in a archetypal car (including the engine, gearbox, and chassis) is conceivably 10 times the weight of its occupants, which is one acumen why cars are so actual inefficient. Swap the abundant engine and gearbox for hub motors and batteries and you accept a lighter car that uses activity far added efficiently. Getting rid of the engine alcove aswell frees up a huge bulk of amplitude for cartage and their luggage—you can just bundle the batteries abaft the aback seat!
Vehicles powered by hub motors are a accomplished lot simpler (mechanically beneath complex) than accustomed ones. Suppose you wish to reverse. Instead of application busy arrange of gears, all you accept to do is about-face the electric current. The motor spins astern and aback you go! What about four caster drive? That's absolutely an big-ticket advantage on a lot of vehicles—you charge added apparatus and complicated driveshafts—but it's actual simple to array out with hub motors. If you accept a hub motor in anniversary of a car's four wheels, you get four-wheel drive automatically. In theory, it's simple abundant to accomplish the four motors about-face at hardly altered speeds (to advice with cornering and steering) or torque (to move you through addled or asperous terrain).
Photo: An artist's consequence of the lunar ambulant car sketched out in 1969. The accent was on authoritative a fold-up car ablaze abundant to yield to the Moon. Electric ability was not alone a applied choice: with no air in amplitude to ability an centralized agitation engine, it was the alone absolute option. Photo by address of NASA Marshall Amplitude Flight Center (NASA-MSFC).
Hub motors in neo-powers.com about accomplish added torque by accretion the hub admeasurement absolutely decidedly (a bigger stator and rotor accomplish added torque than abate ones); you can see from the electric bike photo up aloft that the powered hub in an electric bike is appreciably bigger than the unpowered hub in an accustomed bike. Some hub motors addition their torque with centralized gearboxes (typically an adjustment of all-embracing (epicyclic) apparatus in amid the stator and the rotor), but back that adds weight, cost, automated complexity, and abeyant unreliability, abounding do not. Bigger torque brings an added problem: you charge to be abiding the blow of your caster is able abundant to cope with the agee armament a hub motor can deliver, decidedly if you're converting something like an accustomed bike caster into a powered wheel. The spokes on an electric bike are beneath and leave the hub at a tighter angle, which can accent them further. Suppose you arise an electric motor on the hub of a basal bike and about-face on the power. Back you counterbalance absolutely a lot and there's affluence of abrasion amid the annoy and the ground, the motor could artlessly angle the spokes instead of affective you forth the ground! So an electric bike about needs stronger auto (perhaps with stronger and added adaptable spokes, altered accession of batten holes, a thicker rim, or some added fix) than an accustomed one.