Researching 26X4 mountain/urban bike tires and electric hubs, and came across a website that's interesting. Busetti.com. They make a 48-52 volt, 1400watt electric internally geared bike hub in 26X4 that has over a 50 mile range, with 25% hill climb capacity and speeds over 30mph. They include controls, regenerative braking, charger, etc... among other things. Too bad the total cost with battery is over $1500. it would make for an interesting, and uniquely powered Servicycle.