(By a bicyclist with a common man's (not an engineer's or bicycle tech's) POV regarding bicycles and motors used to assist bicycling. In other words: Press button - how fast can it go and for how long, and will it take me up that damn hill without too much effort on my part.)
I was looking for a motor for my 20" folding bicycle which I customized with cruiser handlebars and a more comfortable seat. The bicycle seat and handlebars can be removed easily with quick releases and this makes it relatively lightweight and easy to fit into the tiny trunk of my Honda Civic with the trunk lid closed.
So when I went looking for a bicycle motor, I wanted something that would be small, lightweight and easily transportable, yet powerful enough to help me get up that occasional hill or long stretches of incline on my rides around town and outlying scenic areas filled with over 100 miles of bicycle trails, parks, lake, mountains. Oh yes, did I mention, I wanted a kit I could quickly, easily, self-install without an engineering degree or bicycle shop tech expertise.
Previously on my other bicycle - a semi-recumbent - I had installed a front drive 250watt motor. The motor and battery added an addition 8-9 pounds to the bicycle. I didn't want that much weight on my smaller folding bicycle. What I found the most appealing were the friction drive motors. But the biggest complaints about these friction drive motors were:
1. Cost - Some electric friction motor kits cost over $1000. The gas driven kits are less expensive but add a huge heavy motor (like a lawnmower size motor) on the back of your bike.
2. Bicycle tire wear from constant roller friction with the tire
3. Lack of power - not as strong as a front wheel hub motor or mid or rear wheel motor setup.
4. Noise - Loud annoying, attention attracting whirring, whining noise
5. Installation - Some kits required a lot of work and knowledge that most people who are not that knowledgable about bicycles might not possess or be inclined to get that deeply involved.
After further research, I came across Qiroll Technology based in Shanghai, China, founded in 2017 to research and develop electric motor systems. They have a number of friction bicycle motors and batteries. The model I am reviewing is the QR-E 250 Watt, with the B60i and B70 batteries. BOTH the motor and battery and cables weigh between 3-4 pounds (depending on the smaller or larger battery you choose) TOTAL. So that met my personal requirement as far as being light and easily transportable.
I ordered this off E-bay and thought it would take forever to get here from China because of the Covid crisis, but it came within 2 weeks! The kit came in 2 neatly, professionally packed boxes containing the battery and charger, mounting plates, screws, zip ties, throttle and battery cables, extra friction plates, as well as instructions. What sold me was the video of the QiRoll Kit...It looked simple - simple to install and easy to use, lightweight and relatively inexpensive compared to all the other bike motor kits I'd spent countless hours researching.
A big concern for me before ordering this kit was the length of the throttle cable as I have cruise handlebars that also needed the cable long enough to clear when I took off the handlebars to pack into my trunk. I needed at least 70 inches/178 cm. The throttle cable is 78.5"/200cm. BTW, the battery cable is 27.5"/70cm.
Also included are a number of different size mounting plates and various sets of mounting plate bolts as well as zip ties and extra friction roller replacement plates.
The motor can be mounted in 2 ways to drive the rear tire. One is at the seat stays or at the chain stays where many kickstands are mounted. Since I have rear fenders the seat stay mounting method would not work. Also, because my kickstand was located at the chain stay, I had to remove it and attach a rear chain stay kickstand which actually looks better than the original that came with the bike.
Chain stay mount.The kit comes with a several sets of various sizes and screws and allen wrench tools to do the installation. Mounting the booster motor at the correct angle for the roller contacting the tire at the chain stays should be such that the distance from the front of the booster to the tire surface is approximately 2 1/2" which also happens to be the length of the allen wrench that you use to secure the bolts through the mounting plates. Then it's simply a matter of using the other smaller allen wrench to adjust the C ring so that it is about 1/8"-3/8" away from the tire with the rotating nut loosened all the way back and the end that touches the roller should be right up against the roller. You should also make sure that the center of the roller is not askew and is contacting the middle of the tire flat on and not at an angle. After you tighten the 3 nuts, the booster motor and roller should be in the proper angle and position.
To use the motor you need to tighten up the rotating knob such that the roller is touching the tire. You'll discover the right amount of pressure for the best result. I usually turn the knob till the tire makes contact with the tire and then give it another 1/2 - 1 full turn more. It will vary on how much wobble your tire has I suppose. The trick is to get the tire in contact with the roller such that one full revolution of the tire has as much constant contact between tire and roller. You don't want too much pressure or too little as that can cause skipping or undue tire wear.
Battery and throttle connected to motor.Your almost through. All you have to do is connect the throttle cable and battery cable to the motor and put the battery in your water bottle holder. Finish up by neatly ziptying all the cables and you're ready to test drive.
Battery in water bottle holder.
UNDERSTANDING AND USING THE ELECTRONIC CLUTCH MOTOR
I was a bit confused at first on how to use what I called the throttle. This by the way is mounted on the underside of the left handlebar grip. You operate it by depressing the lever with your middle or ring finger which gives you power. The button is also accessed with either finger to change the mode in which your motor will operate.
Throttle zip tied on the underside of left handgrip positioned so that ring or middle finger can press lever and reach mode button.
There is no ON/OFF switch on the battery or motor. When you want to conserve power you can go into sleep mode by holding the button for several seconds which will activate a green light on the front of the motor. Or you can turn it off completely by disconnecting the cable from the battery in your water bottle holder.
There are 3 modes:
1. GREEN LIGHT/Sleep Mode - a green light that blinks on the motor. You enter this mode by holding down the button for several seconds. You can still ride the bicycle with no motor assist in this mode.
2. RED LIGHT/Power/Pro/Sport Mode - You can wake up out of the sleep mode by pressing the lever/throttle which will instantly activate the red light which is the Power mode that gives you the highest level of boost that this thing can provde. Once you start peddling you can press the lever which will give you speeds up to 13mph without peddling and more if you do peddle. Mind you that's my personal experience with a total bike/rider weight of 200 pounds. It may vary according to your own bike weight, type of bike and your weight.
3. BLUE LIGHT/Eco Mode- This is the Economy mode in which the booster just gives you a bit of help while you peddle. You have to hold down the throttle lever. If you brake or stop it stops the roller from rolling against the tire.
3 different color light mode indicators on the motor: green-sleep/red-power/blue-eco.
You can switch between RED/Power and BLUE/ Eco modes by pressing the button. The motor will automatically enter Green/Sleep mode after 10 minutes of inactivity/no peddling.
You can manually separate the roller from the tire by twisting the clutch knob which is used to push the roller up against the tire or separate it from it. Once you loosen the clutch knob you have to manually press the roller down to insure it is not touching the tire. You can then ride your bicycle without any motor assist.
Lets talk about drag. Since the roller is in constant contact with the tire you may be wondering about that. I can honestly say you feel no drag when you are in the Power or Eco mode, and I didn't really notice that much difference in the Green/Sleep mode either.
As far as noise, this is where this motor outshines all the other friction motors. You really don't notice it. And as I rode my bicycle around, no one turned their heads, no one seemed to notice. And if I didn't know I was the one riding the bicycle with an electric motor, I wouldn't have thought of the tiny whirring noise I barely heard either. As it is the motor (1.1 pounds) and battery (B60i/1.54 pounds) is so small and light, and tucked away at the chain stay and in the water bottle holder that people don't notice it unless they're looking for it.
On my first test ride I reached speeds of 13 mph with no peddling which is a decent speed for me. I really don't want to go too fast. With peddling it was easy to reach 18mph and probably could have gone much higher but didn't want to. That was on level paved ground. Going up a steep hill which previously took away my breath away while standing and peddling, I used the Power mode and peddled from a sitting position going up the hill at 8mph. Total distance of my first ride was about 7.5 miles and I used the Eco and Power mode interchangeably throughout the ride. Naturally the Power mode uses more battery power. But with that being said there were still 3 out of 4 battery indicator display lights lit. Remember, this is a folding bicycle with 20" wheels and 7-speed Shimano internal gear. So on a larger bicycle with more gears, you probably could reach the manufacturer's claims of 27 mph.
Battery light display
This is the manufacturer's explanation of the 4 blue battery indicator lights:
4 lights on = 100-80% power
3 lights on = 80-45%
2 lights on = 45-25%
1 light on = 25-10%
1 light flashing = 10-0%
BATTERIES - B60i and B70
The B60i is smaller and has less power.
Rated at 6 Amp Hours.
Weight 1 lb 7.7 ounces
Manufacturer claims 80% capacity after 500 full charge cycles (works out to 2-3 years -depending on usage - before 80% capacity)
The B70 is a larger battery more power
Rated at 9.8 Amp Hours
Weight: 2lb 6 ounces
Manufacturer claims 80% capacity after 500 full charge cycles (works out to 2-3 years -depending on usage - before 80% capacity)
Based on subsequent rides, I believe the manufacturer's claim of getting 20-30 miles on the B60i using the Eco mode (motor and peddling) to be accurate. I'd say you could depend on 25 miles out of the battery in Eco mode. I don't usually go more than 10-12 miles on one bicycle ride and the occasional 20 mile ride on level/slight incline paved road, so this is quite adequate for me.
The B70 is slightly heavier and the claim of 30-40 miles in Eco mode, also seems in the ballpark.
REQUIREMENTS and CONSIDERATIONS
The QiRoll kit seems adaptable to just about any bicycle and if in doubt the seller on Ebay suggests you send pics of your bicycle setup for advice on if and how the kit may work on your particular setup as far as stays placement, space, tire type, etc.
This is how the seat stay mount looks as opposed to the chain stay mount on my bicycle.
Other things to consider is that the tire must be a relatively smooth flat (no knobbies) continuous pattern type of tire so that the roller can make the best contact with the tire. My Marathon Schwalbe's (e-bike ready) worked perfectly. The roller itself on my motor had a flat relatively smooth rubber plate unlike the abrasive almost sandpaper grit I see on other friction drive rollers. Extra rubber plates were included, in case you had to replace the one that came with the motor. Replacement is as easy as using your fingers to pry off the old rubber plate and pressing on the new one.
The smoother the tire, the better the contact and effectiveness. Knobby tires won't work.
If your tire treads have a lot of grooves, these might trap gravel or little rocks and it could adversely affect the roller plate. So inspecting the tires occasionally and removing any little rock stuck in and protruding from your threads is a good idea. Personally, I haven't had any issues with this. The grooves in my tire treads don't really pick up much.
The QiRoll company claims that very little tire wear occurs with their smooth rubber plate and that it also works well should your tire get wet. I haven't tested this out too much, although the few times I went through a puddle, I noticed no slipping or decrease in performance.
This isn't the most powerful bicycle motor kit but for my 20" folding bicycle it goes fast enough and helps me get up that occasional hill or long stretch of incline. It was easy to install and easy to use. I do wish the mode indicator was on the throttle so you could easily see it on the bicycle handlebar instead of looking way down at the motor.
With that being said, I think this kit meets a lot of critical points that I mentioned at the outset earlier:
1. Cost (motor, cables, throttle, battery, charger, mounting plates, zip ties, instructions)$299-$400+ plus tax and shipping. Price may vary depending on where you buy it and what size battery is included.
2. Tire Wear: minimal if any on my Marathon Schwalbe
3. Power: Adequate for my needs...long flat roads, some inclines and occasional hills.
4. Noise: very minimal - you really don't notice and neither do other people.
5. Installation: Easy, fast (allen wrench tools provided in kit). I'm pretty fussy about cabling, I'd say arranging the cables to my picky perfection took more time than mounting the motor and adjusting clutch knob and roller on the motor.
I am in no way connected with QiRoll, just a customer. But when I find something good I don't mind sharing it with others and I'm really enjoying this motor. For those further interested you may go to the QiRoll website or search on Ebay. Here are some other videos on the Qiroll electric friction drive bike kit:
QIROLL QR - E installation w/English subtitles
QIROLL E-BIKE Electric bike kit qiroll.com
Qiroll Replace friction tape
If you have any questions about this, I will be glad to answer to the best of my knowledge. I'm a non-technical person, more of a common sense, hands on, get the job done type, so don't expect any deep engineering/electrical knowledge from me about any of this other than at the level that I've just presented.