How to Create a Smoothie Making Human Powered Bike Blender for Less Than $25




Introduction: How to Create a Smoothie Making Human Powered Bike Blender for Less Than $25

About: I'm a mechanical engineering student at the University of Minnesota. Sometimes I climb trees. Sometimes I study. Tree climbing is more fun.

I love biking. I also love smoothies. That's why I was really excited when I read about the B3 mini from rock the bike in Make 11. However, upon visiting their site I was dismayed at the cost of the blender, about $250. Thus, not knowing if it would work, or if it was even legal (patent infringement and such) I set of to create my own bike blender.
This instructable documents how to create your own inexpensive, energy conserving, bike powered blender. Since appliances account for over 20% of your electric bill, this is one less energy consuming machine in your house. And making a fruit smoothie is twice as good for you as before; both in nutritional value, and also in the exercise you get. It isn't an incredibly difficult build, and even the most inexperienced Maker should be able to complete it in less than 3 hours (not counting glue drying time).

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Step 1: Necessary Materials

Materials needed:

Blender: Theoretically, any blender would do. I'm using a Hamilton Beach personal blender that was practically made for this project. The two key things needed are that:

1) The blender jar locks in place
2) There is a transmission disk, instead of the motor connecting directly to the blades

A M4-.70, 19cm long bolt: In a perfect world, a bolt of this size would exist, but the longest I could find was a 7 cm. If you can find one, great, otherwise you need: 3- 7 cm, M4-.70 bolts and 2 coupling nuts of the same size.

Old bicycle inner tube

1x8 board

3x4 metal plate

2- 1.5 in. diameter wooden wheels

4- 2 inch bolts of any size, and 4 matching nuts

2- 1 inch wood screws

2- M4-.70 Tee nuts

Bicycle rear rack: any rack should do.

Step 2: Tools Needed

Tools needed:

Wood saw

Hack saw and table top vise (only if you need to make the 19cm bolt)

wood glue

Drill and drill bits

Tape measure




medium clamp


2 1/4 inch hole saw

Step 3: Void Blender Warranty

Once you have your blender, the first step is to remove all the useless, power-draining junk.
For the blender I used, the process went like this:

Remove bottom plate, cut the power cord, then remove the second bottom. Now you should have full access to all the guts. By gripping the motor with a pliers and holding on to the transmission wheel with your other hand you should be able to unscrew the motor from the wheel.

Throw out (or better, save for a later project) the motor , two bottom plates, and power cords. All you need is the base, the transmission wheel, and the little black rubber piece in the hole.

Step 4: Make Inner Wooden Supports

Using the hole saw, cut 3-2 1/4 inch rings out of the 1x8 board. Glue them together in a stack using wood glue, clamp, and allow to dry.

Once dry, use the saw and file to cut 2 notches on opposite sides of the cylinder. These notches will allow the cylinder to fit between the two columns in he base for the original screws.

Step 5: If Necessary, Construct the Long Bolt

I couldn't find a at least 19 cm, M4-.70 bolt. If you were lucky, or just more skilled than myself, you can skip this step. For the rest of you, this piece must be constructed.

First, cut the heads off 2 of the 7cm bolts using the hack saw and vise. If you don't know how to do this, there's a good tutorial here: quick bolt shortening tutorial.

Then cut a 4 cm piece out of the 3rd bolt. Thread all the pieces together using the coupling nuts, with the order long, short, long.

Step 6: Construct the Base

Cut a 8 inch piece off the 1x8. This will form the base of the blender. Next, drill a hole wide enough for the long bolt to fit through about three inches from the shorter side (the cut edge), and centered between the two longer sides (the 8 inch edges).

Line up the hole in the cylinder left from the hole saw with the hole in the base and screw it into position with the two screws. Now you have finished the base assembly.

Step 7: Attach Blender

Slide the blender bottom over the cylinder on the base assembly, making sure that the grooves line up.

Then insert the long bolt through the hole in the base and out through the top of the blender bottom.

Screw the transmission wheel on the long bolt.

Step 8: Attach Friction Wheel.

Using the hammer, pound the 2 tee nuts into the 2 1.5 in wheels. Then thread them onto the long bolt.
It is important to thread them so that the tee nuts are on the outside, not in between the 2 wheels. Otherwise the wheels could fall of, even though the nuts stayed in place.

Next cut a 1inch piece of the old bike inner tube. Slip this over the wheel assembly.

Now you have finished the bike blender. All that is left is to install it.

Step 9: Fit the Blender to the Rack

Set the blender assembly on your bike rack so that the friction wheel sits on the left side of the tire. If you put it on the right side, the blender will spin counter-clockwise and unscrew itself.

Now you need to adjust the friction wheel so that it sits on the back tire correctly. Optimally, both 1.5" wheels should be touching the tire at all times (see photo).

Step 10: Attach Metal Plate

This step is best accomplished with the bike upside down. Once the bike is flipped, align the blender assembly in the same position you had it in step 9.

Then place the metal plate on the bottom of the bike rack. Make 4 marks where the corner holes line up with the wooden base.

Drill out these holes so that they fit the 4 bolts you have.

Then, with the bike still upside down, push the bolts through the plate, through the bike rack, and out through the wooden base. Lightly twist on the nuts so that the base can still be adjusted.

Then flip the bike back over.

Adjust the base of the blender so that the friction wheel sits against the back tire, and then tighten down the remaining nuts.

Step 11: Use It

This blender can be used for anything you would use a normal blender for. Simply add the ingredients and bike. However, here are a few hints to optimize use:

1) Use a bike trainer so that you don't have to go around the block to make a smoothie. New ones from the store can be expensive, but you can find several on Craigslist or Ebay. You'd be surprised how many people bought them to exercise, but never used them.

2) For really hard things such as ice, it is best to start moving before adding the ice, otherwise the blender just jams. Again, this works best with a trainer.

3) Check the parts regularly for wear and tear, especially the rubber ring. A blender breaking can ruin a good smoothie.

Also, here are good Smoothie recipes.

Step 12: Future Additions.

For this blender to truly be mobile, the ingredients need to become mobile to. But on a hot summer day, when I really want a smoothie, the ingredients can go bad pretty quickly. At the moment, all I have is an inefficient, heavy ice cooler. As the ice melts, it fills with water and sloshes around. Here are my brainstormed solutions to the problem, please comment and offer suggestions, as ideas are needed.

1) Replace the ice with gel based ice packs to remove the weight.

2) Attempt to build a mini-refrigerator for the back of my bike, but this will be difficult.

3) Use a highly endothermic reaction to cool the ingredients. A possibility is the reaction between Ammonium nitrate and water. Ammonium nitrate is a common fertilizer. The heat of solution of this reaction is -25.69 kJ per mol, easily enough to cool the ingredients while blending, or in some sort of cooler.

Finalist in the
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First Prize in the
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Participated in the
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    86 Discussions


    1 year ago

    Hey there, I'm currently building my bike but I'm encountering a problem.
    Currently, I have installed the components on the left of the bike's tire. The mini wheel component is tightening itself against the middle piece, however, the transmission wheel is loosening itself. Have you encountered this problem before? If so, how did you fix it?

    Also, as the blender is on the left side of the bike, the blade is turning anticlockwise instead of clockwise.... I'm using the Target 30aud blender..


    5 years ago on Introduction

    Es muy Interesante, el proyecto por ustedes implementado, felicitaciones, si fuera posible de la información, me fuese enviada a mi correo, en traducción al español

    Cordial Saludo


    Diego M Restrepo M


    7 years ago on Step 8

    Do you have any suggestions as to how to keep the wheels from moving as they spin around?

    This tutorial has been really really helpful in my bicycle-blending attempts. I'm using a stationary bike, and constructed a simple base stand from PVC pipes for about $15. I'm having troubles both getting the wheels to move the shaft, and, if they are moving, to not move up the shaft, away from the moving wheel on the bike.



    7 years ago on Introduction

    Thanks -- we constructed this bike blender and it worked great. We have some questions/comments/feedback.
    1) We used tee nuts on the wooden wheels as you suggested, and a single long threaded rod, but how did you keep the wheel assembly from 'climbing' up the threaded rod (which is bad) rather than turning the rod (which is what is desired). Our solution was to place a lock nut on the threaded rod above wheel assembly and that worked well.
    2) What is the purpose of the metal plate? We skipped it without any obvious problems.
    3) our long threaded rod tended to 'climb' upward as it rotated (the hole we drilled thru the wood was just a bit larger than the threaded rod, so it would naturally climb as the threads rotated) and this tended to push the blender jar out of its cradle as we pedaled. (I guess your assembly didn't have this problem?) Our solution was to have somebody physically push down on the blender jar at all times, but eventually the jar was ejected from the blender and broke :( any ideas for us?


    Reply 7 years ago on Introduction

    1) I used two wheels, each with a tee nut in it. If you counter turn them so that they tighten and press together, they should stay in place and not climb the rod.

    2.) I used the metal plate to attach the blender to the bike. It wasn't the best method, but it's all I had on hand at the time.

    3.) It's been a long time since I made this/used it, but I don't think I had this problem. I'd suggest counter turning two nuts below the board, and placing a washer above them. This should keep the rod from climbing up.

    Good Luck! Let me know if you have any more questions:)

    Hi there, I'm having trouble getting the motor out. Attached is a picture of the inside of the blender. Advice?

    bike it, like it
    bike it, like it

    Reply 7 years ago on Introduction

    I've tried unsuccessfully to hold the white disk while using pliers to twist the motor off. It seems like I'm missing a step...


    Reply 7 years ago on Introduction

    Gosh, it's been a while since I did this. If this is the same blender (and they haven't made any major revisions), I think you have to grab the white disk, and unscrew the motor rotor (not the housing). Let me know if that doesn't work. It may be reverse threaded, I can't remember.


    8 years ago on Step 12

    Be nice... Ice is the way to go. But you've gotta carry the ice in cooler. Use an Instep double trailer. These can carry 100 pounds. Ice, cooler, ingredients. cups, straws, alcohol, uh, hand santizer in backpack. okay. Im psyched!!!!


    9 years ago on Introduction

    Hi - I am organising an eco-creative event for a non-profit org and would like to be able to use the above image to promote a workshop for making bike blenders.

    Is there any chance I could get the main/top image of this page a little larger for print? Or find another similar simple but colourful one at a high resolution and creative commons copyright or other?

    Thanks alot --

    Mig Welder
    Mig Welder

    9 years ago on Step 1

    Couldn't threaded rod just be used instead?


    Reply 9 years ago on Introduction

    I wish I had the resources on making one of those. I quite fascinated on the different ideas people are coming up with in generating energy. The most popular I've seen is about stationary bikes. This article summarizes them (scroll at the very bottom of the page) and I just can't wait to implement those ideas myself! But I still need time to recovery from my surgery :(


    Reply 9 years ago on Step 1

    Threaded rod would be ideal, but as I stated in the instructable, I couldn't find any thread 7 mm rod. None of the local hardware store's carried it, but they did carry shorter bolts, which I could combine together to make it: "A M4-.70, 19cm long bolt: In a perfect world, a bolt of this size would exist, but the longest I could find was a 7 cm. If you can find one, great, otherwise you need: 3- 7 cm, M4-.70 bolts and 2 coupling nuts of the same size."


    11 years ago on Introduction

    Good work! I was planning on something like this myself but you beat me to it. I have been having a problem sourcing a cheap blender - the cheapest I've found has been $40 (I'm in Aus), how do you tell in the shop if the blender is the right type?


    Reply 9 years ago on Introduction

    See my comment above, just make it work by using metal epoxy if the parts aren't a perfect match. Beware, this is for low-torque load are on your own if you use it for other things!


    Reply 11 years ago on Introduction

    Really any blender will work, some just work better than others. Try to find one that has the jar locked into the base, as that is necessary to stop the smoothie from spilling. Also, the project is much easier if you use a blender with a transmission wheel instead of a post connecting directly to the blades. I used a blender I bought online from target, which I think you can do in Australia: Hamilton Blender. Otherwise, just try to find a cheap one that fits the specifications.


    11 years ago on Introduction

    Great instructable - I have had complications, though:

    On the first blender I took apart (Oster brand), The rod has some odd tread pattern that's neither metric nor standard. I went to 3 different hardware stores and asked for help, but no coupler nut or any other nut screws onto the rod right. I was able to partially screww one coupler nut on but since the threads don't match, it doesn't go on straight, so the wheel I attached spins obliquely.

    The second blender, an older Hamilton Beach, has a rod that is smooth, not threaded, so I don't know how to extend it.

    I got both of these blenders for free, so no big loss. I'm using a skateboard wheel instead of wooden wheels.


    Reply 9 years ago on Introduction

    Two words I love lately..."metal epoxy", small tubes available...put it exactly where you want it, wipe away any "strings" while it is still wet and soft like toothpaste, as when it hardens, you will have to file away any unwanted drips. I have successfully repaired welded outdoor furniture, antique stained glass lamps, attached threaded rods to un-threaded ones, and repaired thrift-store silver pieces that were broken...enough to get more "decorative" life out of. Just glue the head of the bolt to the bottom of the shaft. glues metal to other things, too; I learned about it from someone who repaired a crack in an engine block of a VW and then drove it to CA without any problems. (User beware!)