I bought this kit a few months ago and it is working perfectly so far. It runs under 18mph or over 17mph at its fastest and pedaling hard I can hold 22mph as measured by my Garmin 76s gps. I calculated my gas savings at $80 to $120 so far. I first installed it on a target type Schwinn girls bike for a week, and then on my Trek 3700 MTB(China Made) Shimano/etc $259 on sale and 25lb weight. The trek used a 31.6mm seat post so I bought 4 longer bolts at Lowes for $2 for the mounting hardware. (which vibrates loose once a month - use thread lock)The whole system weighs under 40lbs and I can carry it up stairs. The big selling point for me over the Clean Republic bike was the low price, a throttle and not a switch, and Panasonic Brand Batteries. I stress the Panasonic brand because I have had good luck with my Panasonic 1997 36" hdtv, stereo, Cordless phone, electric razor. The stuff seems to last at least 13 years and rates very high in consumer reports. I am confident the batteries have the same quality control that protects their good name. So far so good. I treat the battery like a new born baby and feed it after each ride and remove it from the bike when its locked up. I'm in my late 40s 6'2 190lbs and reside in The San Fernando Valley of Los Angeles. I timed 2 "racing" speed runs to my gym at 4.2 miles The bike took 19 minutes, the BMW 328ic took 13 minutes.
I made a few adjustments to the bike that I found necessary.
1) Bell Light set $26 at walmart - so I can ride at night, which I love to do nowhttp://www.walmart.com/ip/Bell-Sports-L ... t/14003642
2) Serfas full suspension Saddle - relieves lower back pain from long bumpy rides with back pack http://www.amazon.com/Serfas-Suspension ... 62&sr=1-10
3) 2 bike locks to prevent theft, added a Kryptonite U lock.http://www.amazon.com/Kryptonite-Keeper ... 28&sr=1-10
These do add weight but I also cut off the brake cut off switches, My brakes have the shifters built it. http://www.ev-universe.com/brakecutoffswitch.aspx
Cutting them off lets the throttle still work.
The other big challenge is finding the best route to your destination. I use back roads that cross main roads with a traffic light. I also use the many bike lanes available in this area, even some improved sidewalks. The padded seat helps with some of the bumpy deteriorated back roads. When its cold 4 layers is not enough, you will need some type of windbreaker.
A few of my riding styles are to
1) not pedal at all, you arrive without any sweat.
2) Pedal at the start to save some battery.
3) use the battery to start and pedal after you reach 17mph.
4) Motor and pedal to go as fast as you can.
5) don't even use the motor.
What is Priceless, pulling into a gas station and looking for an outlet.
Also stopped at an intersection or by a bus stop full of people, lift the front wheel up a millimeter and hold still and spin it while holding still so it squeals. everyone looks in amazement. I also notice I can keep up with city buses. At 35mph they pull away from me but I catch up at every stop they make.
The motor is very quiet and no one has even noticed it is electric. I think dogs can hear it. It is louder when its starting up 1 to 5 mph. There is more stress on my bike as I ride it more. I had to tighten the rear brake as it is wearing down. My stock rear wheel needed truing but I fixed that my self. I also keep 50lbs of air in my tires so it goes faster. At 30lbs its a softer ride maybe slightly slower. A 29mph Head wind while riding slightly up hill reduced my speed to above 15mph. The times I ran it completely out of Juice it slowed to 15mph. I have only encountered one big hill so far and I pedaled very lightly and it went up at full speed. I raced a 12 year old on his BMX bike, I used only the motor and no pedaling. He pulled ahead and head a 10 meter lead for about 50 meters before he tired and I passed him.
My conclusion is so far so good. I read about people with Clean Republic who's battery quits after a month but this Panasonic gives me confidence. If the battery does quit in the future I will get the cells my self or have someone upgrade it cheap, under $200. The added thrust to the bike makes me feel 20 years old again. I am in much better cardio shape from all the riding I do now. If I have to rest I am still traveling 17mph. I can get where I am going with out sweating. I studied electric bikes for months and this is the best deal for a Bafang and Lithium Ion. Naturally people want to go faster but I question a bicycle is a good platform for higher speeds. A moped Scooter or Motorcycle has a more durable suspension. In California this Bike kit needs no M1 or M2 drivers license and no registration. I do ride with a helmet and obey all traffic laws, except when racing.