The time has come to build a commuter bike for commuting around the city I soon move to.
I got some requirements that I want to incorporate to the frame, but nothing is set in stone.
-<100v pack so I can use 4410 fets
-Large battery pack build with Enerdel cells
-The biggest hub motor with freewheel I can get my hands on
-If possible, 17" motowheels in aluminum. I want to try mc tires
-All components either downhill specs or stronger
-Power and throttle controlled by CA v3
-Good acceleration and a top speed >80km'h
The basis for the frame is an old Specialized Big Hit. They is some old parts from my other mid drive build and I wanted to recycle them.
The Enerdel cells are large. I really hoped to design a neat and good looking frame, but that did not happend. No way that it was possible to put more than one cell in one plane without making the frame bulky and large. But I wanted a large capacity bike, so I did the best I could.
Battery, 22s2p, 470g x 44= 20.68kg
Hub motor, commonly around 12 kg with wheel
Complete frame ex rear wheel/motor= 22kg
I hope that I can get the weight below 55kg, but I don't care. I am a big man and I can handle 55kg. I just hope that the bike can handle my 115kg's.
Frame is built with 4mm 5052 aluminum. Easy to weld and can be bent without cracking. I found out that the aluminum was very dirty, so I had problems with getting good welds. I used a lot of gas and time just to heat up the aluminum and get the contamination out.
For the motor I hoped that QS motor could supply me with their 273mm motor, but since they don't reply to mails anymore I wont send them any money before the explain themselves. I am open to any suggestion for a big hub motor with lots of torque.
Below is a couple of pictures of what I did in one session. I think it is possible to make a frame from scratch in one day if you have enough welding gas, food and patience