Hello, just joined today, to answer and reassure buyers on Colt 604.
I had one since april 2018. Had no problems assembling it (followed the online video), with just the front fender being difficult to adjust without rubbing the tire. Did 500 km on the bike so far. Extremely happy with it. Got 200 km on the first charge by pedaling a lot and using only level 1 assist on slopes. Now I use mostly level 2, still pedal a lot and get 120-150km on one charge. Am not an athlete, and weigh 190 lbs, and as my name says, am OLD.. so no worries about battery life.
A second great area is the brakes. I practiced ( and flat spotted a bit the rear tire in doing it,) and can stop from 20kph on a measured 7% downhill slope in 7 feet!! Great sense of safety for urban riders, and in my case on bike paths, there is always the stray dog, or ball, or child on his first bike that cause hairy moments, so great idea!
A third great area is the tires. I can fall off the paved path into gravel and come back on, still running parallel to it, even if there is a 2" curb, just with the grip on the side of the tire. Again great sense of safety. Also on any fast turns on asphalt where there is small winter-traction gravel left on it,( 2-4mm stones) the wide tires won't slip sideways as with normal 700c tires with 70 pounds in it. Even at 35-40 pounds the tires have excellent rolling resistance. ( I understand that the hysteresis loss is less on these than on the 700c tires.) Also did a 30 km ride on a total gravel path in a park , at a good clip, with big slopes, and never a wobble or a slip. So good choice, not too big, not too small.
Other likes: The rear brake light; the integrated solid rack; the step-through;
The saddle is not the greatest; comfortable for a young guy, but no tilt adjustment possible. Us older folks have sensitive tubing ending in that area, plus sensitive vertebrae, I think there should be a senior saddle option, one with visible springs like they have in Europe, much cheaper and lighter than any suspension system, they are only 30 $ or so ..
The chain only fell off once , ( between frame and plateau), when I did a gear change almost at a standstill in a steep slope. Would probably have come off on any bike. I pulled it back on with my fingers only, no problem.
The only puzzling thing that happened on two separate occasions is that after parking the bike in the sun for half an hour on a hot day, it lost all power and the display showed flashing empty battery whenever I tried to get anything more than level 1 assist from pedals: any throttle, or any attempt to get level 2 or higher would stop all power to the motor. Battery was still at half full. In both cases I would need to shut down the display with the button, and reboot up again; and this happened several times, whenever I tried to increase the demand on the bike. I limped home on 1st level and let it "rest", and next day it was working perfect. I deduce from this that either their current controller is too sensitive to heat, or that the battery has an internal thermal protection circuit that is a bit sensitive. OK, it was a slight-panic problem, but it is far better to have too-sensitive alarms than abusing the battery... So: park in the shade on hot days...
Finally: I doubt that running the battery down to zero and charging it everytime to 100% gives the best battery life ( highest number of recharge cycles); from my experience as a modeler with Lithium batteries, and from research I read, it seems that the sweet spot for optimal life is to recharge at 20% and to not more than 80%.. It makes sense; except that there may be a cell-balancing cycle that only is performed when the battery is near total charge, by electronics inside the battery.... This information I could not get from Mike, who was not aware of these details. So, if anyone knows more, or wants to know more on this, let me know and we will try to get to an answer, maybe from the factory with Mike help.. a new battery is expensive, and if we can make ours last longer we all win.