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Hub Motor on Old Specialized Hardtail

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  • Hub Motor on Old Specialized Hardtail

    Started with an older Specialized Steel Hardtail and added a 9C clone hubmotor. Got a pair of suspension forks from a guy who had upgraded forks and installed those along with a threadless headset, shorter beefier stem and a pair of 31.8 bars. The hubmotor's axel flats fit perfectly in the dropouts and I used a pair of torque arms ordered from Luna, had to slightly modify the torque arm on the derailleur side to clear it, Luna's torque arms are fairly thick, real decent for the money, they feel solid. Twist throttle, no display, just a three LED indicator for battery level on the throttle.

    Paired with a 52V battery the motor had good power and pulls steep hills real well (I'm 125 lbs, a slight breeze could blow me up a steep hill I'll admit). I installed a set of Grin Heat Sinks and Statoraid to help keep the hub cool, seems to be doing it's job, I tested it up about 3/4 of a mile of real steep hills above my house with the throttle wide open, stopped and felt the temp on the motor-barely felt warm. After about 5 more miles of really cranking the throttle it still barely felt warm, not even 100 degrees. So far the controller hasn't smoked, we'll see how that goes over time but neither hub, controller or battery felt warm after a hard test on a 90 degree day.

    I can see one definite downside to hubmotors, changing flats, the BBSXX motor setups make that much easier. I installed a real thick tube and liners before even getting started on this one, the first flat I get I'll be putting a Marathon Plus tire on it with Slime, pain in the butt to remove the torque arms and realign all the washers, reinstall the torque arms.

    I have 2 bikes equipped with BBSHD's so I wanted to see what an inexpensive hub motor could do. So far I'm pleased with the performance, very fun bike. I'm not real big on linear pull brakes but after adjustment these are stopping nicely, with the suspension fork I have the option of putting a disk on the front, will just need a disk wheel, brake and disk. I have the bike set up with a front ebrake right now.

    Out of the insane amount of wires coming off the controller I hooked up power wires, 1 ebrake, throttle plug and motor to controller plug, now I have to hide the rest of them somehow, the usual tidying of the wires.