dogman dan said:Best bang for how much bucks should be the question. If its a few more bucks, then the superior wheel build you get from Grin, or E-Bikekit would be the way to go. Both of those build the wheel in house. Cheap uses china built wheel.
The cheap kits from E bay, they can break spokes in the first mile, or run thousands of miles. A lot of that is determined by doing a bit of inspection and tuning before you ride, and more in the first few hundred miles as the cheap spokes stretch out. Then they settle in and will be reliable enough, unless your own ass weighs 350 pounds.
As for the cheap controllers, they can work fine. But if they don't get more, they are cheap after all. One that works when you get it will work a year or two, then something fries inside. Lower wattage ones could last longer, but you will need 30 amps to get into 30+ mph.
Usually the really cheap "48v 1000w kits" like the yes kit come with a 6t wind, producing 30 mph. Others like E-Bike kit tend to be 7t motors which produce 27 mph on 13s. Grin or EBK actually come with warranties, which does mean they tend to supply more reliable everything. Can't afford a year warranty on junk.
If you want more speed than 27, and cheap is your real goal, go with the cheap e bay kit. But keep up on your spoke tensions.
If you want more power and possibly more speed, then go with much wider stators, so you can go 40 mph later without having the motor burn up. Thats more bang for sure, but also more bucks.
Questions regarding the E-Bikekit offerings...Do they offer a Direct Drive Hub Motor/Wheel with a Kv/winding that will exceed 20 mph@48v? Only DD motor/kit I saw said "20 mph at 48 Volt" and I'd like something that will do ~30 mph@52v.