About: I love to build things. My love affair with destructing, constructing and reconstructing stuff began when I was very young. When I got a new toy the first thing I did was take it apart to find out how it wor...

I live about 10 miles away from my job which meant I was using about a gallon of gas a day just to get to and from work. I figured there had to be a better way. I looked at electric bikes and conversion kits but the cost was way more than I wanted to pay. Then there was the 49cc 2-stroke conversion kits. I found these as cheap as $140 but wasn't really sold on the idea of altering the bike so much. Then I remembered the "Stinger" from my childhood. These were friction drives we bolted to the back of our bikes. I started doing a little searching and found friction bikes of all kinds on YouTube. These were various motors mounted to the back of the bike with a peg on the output shaft making constant contact with the tire. This meant that every time you stopped the bike you would have to restart the motor. If something happened to the motor you would have to get off and adjust a turnbuckle to ride the bike normally. I wanted to ride the bike powered or un-powered at any time and not have to restart the motor every time I stopped. So after watching countless videos I came up with my own idea. I would incorporate some kind of clutch system in my friction bike. Presented here is what I came up with. Unfortunately I failed to take pictures during the build so I only have pictures from the finished project. By the time you finish this instructable you should have a good enough understanding of the concept to build one yourself. If you already have a bike and a motor and do some salvaging you should be able to complete this for around $50. Here is what I used:

GMC Denali 700c Road Bike

26cc Weed Wacker Motor

Schwinn Seat Tube Bike Rike

1 x Sunlite ATB Shift/Brake Lever Set - 1 Pair, 3x7-speed, 2 to 1, Black

1 x Tektro RX 4.1 Reverse Brake Levers Black

Bell Shift Cable Kit

1/2" Aluminum "U" Channel

1/8" x 1" Aluminum Flat Bar

Misc. Nuts, Bolts, and Spacer (I used all stainless steel but you can you what you have}

1/2" Plywood (A piece of scrap)


Cable Clamp (Salvaged from another bike)





Tape Measure

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Mounting the Motor

Before mounting the motor I cut away the parts of the plastic casing that I didn't want. Next I attached a bike axle peg to the crankshaft. The way to do this depends on the motor you are using. For mine I threaded the the end of the shaft with my tap and die set. I then slipped the peg over the shaft and used a nut and a nylon lock nut to hold it in place. Once you decide on how to attach your bike peg you must make a way to mount it to the bike. Using a piece of cardboard as a pattern, I designed a swing arm, that I cut from 1/2" plywood. I have included the pattern I designed. I then mounted the motor to the swing arm then attached the swing arm to the bike rack mounting bracket. I used a long bolt and a spacer, made from a piece of copper pipe, to align the arm to the wheel. This swing arm system will allow the motor to be moved on and off the wheel by using a lever on the handle bars. In the next step we will mount the rear support system.

Step 2: Rear Support System

The front mounting point is not enough to hold the motor inline by itself so I created a rear support system. I started by cutting 1/2" aluminum "U"-channel to length, one for each side. There is a dog ear over the rear axel on most bikes used for attaching a fender. I used this as my bottom mounting point. For the top I drilled a hole in the rack and used a long bolt and a spacer to hold it in place. The spacers are used to hold the channel vertical. This will keep the swing arm in the same plane as the wheel and keep the bike peg at a 90 degree angel to the tire. I did the same on the other side mainly to strengthen the rack. Next I made a retainer, using 1/8" x 1" aluminum flat bar, to keep the swing arm aligned. I cut each bar to length and attached one to each side of the rear of the swing arm surrounding the channel. These must be tight enough to keep the motor aligned but loose enough to allow it to move up and down. The next step is to install the spring that will lift the motor when you stop. This is nothing more than drilling a small hole in the "U"-channel, slipping the hook of the spring through it, then drill a small hole in the retaining arm and hooking the other end of the spring through it. In the next step we will install the lever and cable to pull the motor down on the tire and the throttle lever and cable.

Step 3: Installing Cables and Control Levers

When I first built this bike I used brake levers I cannibalized from an old bike for the controls. They worked but the dropped handle bars were hurting my back and I had to ride with my hands close to the stem. That made control at higher speeds a little scary at times. I can hit over 30 mph going down hill. To alleviate this problem I went to an old style handle bar (from the same bike I took the brake parts from) but that had problems as well. The original twist shifters would only go so far onto the bar which left very little room for my hand. Getting to the brake levers was dangerous as well not to mention the fact that they were not secure on the bars. While my bike was rideable, I did't feel it was real safe. I decided to blow the budget and purchased a set of integrated brake/shift levers and a set of inverted brake levers. I have linked to these in the intro and the cost for all with shipping was about $38. I can not stress how much safer these have made my bike. The shift/brake levers will be used for exactly that, brakes and shifting. The inverted brake levers will control the clutch system and throttle. To mount the clutch cable I used a cable stay off of a caliper brake and mounted it to the side of the "U"-channel. I then mounted a turnbuckle to the bottom of the swing arm and then, using the cable clamp from the caliper brake, I attached the cable to the other end of the turnbuckle. The rest is zip tying the cable to the frame. The throttle is a little more complicated. Because of the added cable, the spring on the carburetor may not be able to return to the idle position. I used the original throttle cable because it was easy to hook up to the carburetor. The free end of the cable casing had to be secured to the frame so it would not move. I used a regular hose clamp to hold this in place. Then using a piece of copper wire I attached the original throttle cable to the brake cable running to the throttle lever on the handle bars. It will take a bit of experimenting and adjusting to get the casing in the right place to get a full pull on the throttle. Next step is to test the controls and go for a ride.

Step 4: Get Ready to Ride!

Now that everything is hooked up it's time to gas up and go. To start your bike follow the start up procedures for you motor. This is usually just pressing the primer bulb a couple of times. When your ready start riding as usual. When you hit 5-7 mph squeeze your clutch lever to pull the motor against the wheel. Squeeze the throttle lever and your motor should start. Release your clutch lever and let your motor warm up about 30 seconds. Slowly apply the throttle and squeeze the clutch lever fully. Continue applying throttle and let your speed build up. You can get up to speed fasted by peddling if you like. If the peg starts to slip on the tire simply reduce the throttle until the peg engages again and slowly reapply throttle. Controlling slippage is the hardest thing about riding on a friction bike. If you are not careful you can burn through a tire pretty quick. If your careful though a tire will last a long time, I have over 800 miles on my current tire, and still going. I ride this bike to work daily (unless it is raining*) and instead of using a gallon a day I buy a gallon about every 3 weeks. I had a lot of fun building this and even more fun riding it. No matter where I go someone will always ask me about my bike.

If you don't mind being bored for 8 minutes be sure to check out my video. It covers all the modifications of this bike so far.

More Mods To Come!

I have a four stroke motor I plan on swapping onto this bike. This should give me a little more low end torque and a little more friendly to the environment. I am also working on an electric bike, using and old Hover Round style scooter, so stay tuned.

I hope everyone enjoyed this structable and maybe got inspired to build their own gas saver.

*A friction bike will not work in the rain or if the tire gets wet. So avoid those puddles!

I am sure some of you noticed I removed the second gas tank. It started leaking so I had to remove it.

Metal Contest

Participated in the
Metal Contest

Great Outdoors Contest

Participated in the
Great Outdoors Contest

Summer #mikehacks Contest

Participated in the
Summer #mikehacks Contest

Wheels Contest

Participated in the
Wheels Contest

Epilog Challenge VI

Participated in the
Epilog Challenge VI

Be the First to Share


    • Skateboard Contest

      Skateboard Contest
    • Make it Move

      Make it Move
    • Teacher Contest

      Teacher Contest

    35 Discussions


    5 years ago on Introduction

    This is a great little instructable and very clever :) However I have to warn people (for the UK at least but I believe the laws are similar in the USA?)

    Any bike that is powered / power assisted with gas/petrol requires you to have a drivers licence (for a motorbike), for you to wear a crash helmet (technically anyway), and to have a licence plate, insurance and tax.

    Basically, any conversions that involve high voltage (>250w in eu, >750w in usa) or gas/petrol will be treated as a moped/motorbike, which will increase the costs significantly; and gives the police the right to confiscate your bike on the spot if you cannot produce the relevant documents.

    I'm not trying to knock this instructable because it is really really cool, as well as shockingly cheap, I'm just warning people. I'm trying to get an electric bike myself and I've had to do a lot of research into the laws around them. It sucks.

    Thank you for sharing this instructable anyway :)

    7 replies

    Reply 5 years ago on Introduction

    Sorry to say but I don't know where you got the idea that the laws are similar une UK and US ??

    The truth is that the laws in are much more different you might think ! In the US they pretty much can do what they can do in term of custom bikes. Under 49cc, it's considered a moped; no drivers licence, no licence plate, nada !


    Reply 4 years ago on Introduction

    Depends on the state. Here in California if it's capable of speeds over 20 MPH it is a moped that requires an M2 motorcycle endorsement (vs. an M1 endorsement which is for motorcycles over 150cc) in addition to your regular driver's license. Also here, while bicycles don't require licenses, they are considered vehicles and you are subject to all traffic laws (including DUIs) while riding them.


    Reply 5 years ago on Introduction

    When I said that "I believe the laws are similar" I mean't it in the fact that both areas have restrictions on wattage and gas/petrol limits.

    If you read my entire comment, you can see that I mention the differences between the EU and USA when it comes to wattage (250 vs 750).

    When I say that they have "similar" laws, it means that they both have laws revolving electric bikes, both having restrictions on the same types of things. The severity of the restrictions, however, is dependant on each location. The USA, while having far more loose restrictions on electric bikes, do still have restrictions before they are considered motor-bikes and require driving licences to use. They can not do pretty much anything, they can just do more than the UK/EU, for example.

    I hope that clears things up.


    Reply 5 years ago on Introduction

    Thanks Rarnd, and yes, you are right, everyone should check their local laws as they are different depending on where you live. Here in Illinois, USA, you only need to be a licensed automobile driver, the motor must be less than 50cc, cannot reach over 30mph in a one mile stretch, and cannot have a transmission that lets you change gears. No tags or insurance required. There is no helmet laws in IL for motorcycles or bicycles. As far as E-Bikes go, anything goes there. We can have 6000w on our bike, as long as it is electric only and has pedals, there is no restriction, unless of course it is an electric motorcycle then the rules are the same as any other cycle. Again, these are IL laws and yours will probably be different.

    And my country has different laws just depending which state you're in.
    My state for example:

    Riding a power-assisted bicycle

    A power assisted bicycle (or power-assisted pedal cycle) is a pedal cycle with a motor attached to assist the rider. The attached motor may provide assistance but the pedals must be the main means of propulsion.

    In South Australia, there are two categories of power assisted bicycles that may be used legally on our roads:

    • power assisted bicycles with up to 200 Watts of power (the power is controlled by a throttle or accelerator); or
    • power assisted bicycles with no more than 250 Watts of continuous power which meet the definition of a pedalec (the power is controlled by the ride using the pedals).
    What is a pedelec?

    In order to be a pedelec (legal for use on our roads), the power assisted bicycle must comply with the European Committee for Standardization EN 15194:2009 or EN 15194:2009+A1:2011 Cycles - Electrically power assisted cycles - EPAC Bicycle ('EN 15194') and this includes the following.

    • It must be certified by the manufacturer and labelled as complying with EN 15194. The label must have the manufacturer's name, the motor's cut off speed in km/h and its electric motor motor maximum continuous rated power in Watts. The label is often found on the bicycle's frame immediately adjacent to the crank.
    • The motor must be electric.
    • The maximum continuous power output of the motor cannot exceed 250 watts.
    • The rider must pedal to access the power (the motor may operate without pedalling up to a speed of 6 km/h).
    • The power must cut out when the pedalec reaches 25 km/h or sooner (if the operator stops pedalling).
    Road rules for power assisted bicycles

    Riders do not require a driver's licence, motor vehicle registration or compulsory third party insurance. Riders are bound by the same rules as for other bicycles, including the need for:

    • the rider to wear a helmet
    • effective brakes
    • a bell, or other audible warning device
    • a rear-facing red reflector at night
    • a white light to the front and a red light to the rear at night (both may flash) clearly visible from at least 200 metres.
    Differences between a power assisted bicycle and a motorcycle

    A power assisted bicycle is a bicycle with a motor attached to assist the rider. At first glance some motorbikes with pedals look very similar to power assisted bicycle. The main differences are speed, pedal crank spacing, weight, seat position, seat shape and gearing

    A good rule of thumb for deciding if the pedals are the main power source is:

    • if the distance between the inner faces of the cranks is less than 180 mm
    • whether it can easily be ridden without power assistance (you should be able to ride it home if the assistance motor fails)

    If these apply and the motor output is either 200 Watts (or less) or 250 Watts (and meets the definition of a pedelec), then it is a power assisted bicycle.

    If the main source of power is the motor then it is a motor vehicle and operating it requires a driver's licence, registration and compulsory third party insurance. However, few, if any, of these vehicles are able to be registered because they are not capable of meeting registration requirements, such as compliance with the Australian Design Rules. Such vehicles cannot be legally operated on our roads.


    Reply 5 years ago on Introduction

    Wow, you have some really loose regulations in IL! I wish I lived there.

    In the UK, you cannot have a bike that has more than 250w of power, it must have pedals, and it cannot exceed 15.5mph on full-electric.

    Anything more than that, or anything with petrol at all, is considered a motorbike and you have to have documentation, helmets, etc. etc.

    Talk about fun-police! Thanks for the comment though, always nice to learn about how the laws differ and such :)


    Reply 5 years ago on Introduction

    *always nice to learn about how the laws differ and such*

    That's what Instructables is all about, LEARNING! :)


    5 years ago on Introduction

    ContraptionMaker, thanks for sharing your creation with us. I've been trying to figure out how to make a similar motor mount. I was thinking the rear support bars would need to be on opposite sides of the wheel, I've been working for weeks on this but it never works (the spindle keeps riding off the wheel). You have brought forth a great new idea, place the mounts only on the left side and have the rear support act as a guide rail for the clutch action. Out of the box thinking for the win!

    As for troll-people like solsmac, they do not understand. This guy probably doesn't ride long-distances, and thinks his muscles are made of titanium. You will probably never get to race him and his pedal power, but if you did, my money's on the 2-stroke!

    True, this project is not going to change the world. But I'm sure it has already made your life better.

    1 reply

    Yes it has. I love to ride but my knees can't take the peddling anymore. I hope you do a structable on your bike. I'm glad I could inspire you.


    3 years ago

    Thank you sir for a wonderful instructable. I have made my own recreation of this design within two days of reading this article. The design is so simple and revolutionary! I hope to share with you the finished product, it is nearly ridable!

    Interesting, but I bet it's noisy on the road. My ears ring after 20 minutes using the weed eater or chainsaw. Buzzzzzz

    Rarnd, You only need a drivers license ,license plate... If its above 50cc's, but not sure if you need a helmet i assume it depends on the state you live in.

    Just though id clear that up.


    5 years ago

    Like your bike dude. Does it ride smoothly.