The Bicycle Blender Page

How to make a Bicycle Blender
(A pdf of this column can be downloaded at the bottom)
Making a Bicycle Blender is not hard, but it does take some time to gather the pieces, and then go through several steps of construction.  These instructions appear a lot harder than it is because I have tried to cover two types of racks, and two types of blenders, as well as explaining steps well enough for people who have only basic tool skills.
Click on any picture to zoom in for the details.
The Pieces:
We tried to find all our pieces used, to promote reuse and recycling.  Some pieces were donated, others came from tag sales.
-The main part is the bicycle.  Our orange large bike (26 inch tires) is excellent for members of the Hartford football team,  but otherwise the seat is always set on the lowest position.   We ended up making the blue smaller bike (24" tires) because there are so many kids who want to get on and pedal. (fast!)
The tires should be smooth sided road tires, or have the stripe along the sidewall for an electric light generator to ride on.  We had to replace the rear tire on the orange bike because the original knobby tire made the whole bike vibrate uncomfortably.
-There are two parts that proved harder to find, the first is a stand for the bicycle. 
 The orange bike has a permanently attached stand from an old roller exercise machine.  It proved to be wobbly and needed an extra set of rods added further out.
The blue bike has a removable training stand.  After carrying the bikes around for a couple years, this is definitely the better way to go, but these stands are expensive.  We were fortunate to find ours left behind by someone in a newly rented apartment closet.  This type of stand clamps the rear axle by turning the handles, and also folds up for transport.
-The other piece that we had a little trouble finding was the blender
 The first one we found right away, but the second one took 2 months to find.  The best blender has a smooth plastic body for easy cleanup, a plastic hopper because they bounce when someone swings a leg over the seat and accidentally kicks it on to the ground, a fan on the bottom of the motor, not the top, and a metal frame for the motor, not plastic.  You can check the fan and the frame by flipping the base upside down and looking in through the ventilation slots on the bottom of the body.
-The roller that rides on the tire can be made several ways.
  Some people have suggested drilling a rubber stopper,  but drilling rubber is very hard to do accurately.  We used roller skate wheels, but skateboard wheels, and inline skate wheels should work too. The bearings need to have a 1/4" hole in the center, because when the blender shaft is extended downwards, you will use a 1/4"  threaded rod.  The bearings can be stopped from spinning with large dished washers.
-The rack can be made in two ways- by clamping a piece of wood on to a standard bicycle rack, or by cutting out a piece of wood to span from the seat tube to past the tire axle, and making legs to hold it up.
The orange bike uses a standard rack with a small piece of counter top clipped on.  This was easy to assemble, but the rack has to be a design that has a space for the spindle to pass through.
The blue bike has a piece of plywood with homemade legs.  It also has an spindle hole in the plywood that is big enough for the roller to fit through.  Once when the shaft bent, we were able to take the blender off and repair the shaft without taking off the rack. 
-The front wheel chock is made of a piece of scrap 1/2" plywood (3/8" to 3/4" thick will work), with two side pieces of scrap 2x4 lumber glued on.
This helps hold the handlebars steady for safety.
Assembling a Bicycle Blender
Because the blender is filled with a liquid, it is a very good idea for it to be level.  The first step is to mount your bike in it's stand and chock, so that any measurements you make will be accurate.
The rear stand will hold the wheel about 2-3 inches off the ground, and installation will depend on the model of stand you have been able to find.  If you are using a style that clamps onto the axle, try to keep the bike in the center of the stand while you are tightening, so that the weight will be distributed evenly.
The front wheel chock will raise the wheel about 1/2 inch (depending on your plywood thickness).  To make the chock, take two short pieces of 2x4 inch lumber and lightly press one against each side of the tire.  (Make sure your tire has air pressure in it.)
Measure the width across the 2x4 outside edges and tire (8 7/8" in this picture). Now subtract 1/16 inch from the measurement so that the assembly will be slightly narrower and lightly squeeze the tire to hold it.  Cut the plywood base to this dimension in both directions so that it will be square, and then cut the 2x4 pieces to the same length.  Glue the blocks onto the base, lining up your outside edges and clamping overnight.  We cut a bevel on the top using a tablesaw, but if this is beyond your skill level, you can round over the top corners with a file, router, or belt sander instead, and then paint.
Now that your bike is standing up at the correct angle, you can put a level rack on it.  Before making pieces, you need to figure out on which side of the tire to mount the blender.  Looking at the drive connector on the top of your blender base, most connectors have an angled set of wedges sticking up (left picture).  They will only work in the direction where the flat faces are pushing against the flat faces on the hopper.  That is direction your blender needs to turn.  The one in the left picture from the blue bike turns clockwise looking at it from above, and the roller has to be on the right side of the rear tire in order for this drive wheel to work and stay screwed onto the shaft.  The threads inside it are reverse threaded (opposite direction from a regular bolt).
Other blenders have a square drive pin, like the right picture from the orange bike.  There are no wedges to show the direction it spins, but when we unscrewed this drive pin from the motor shaft, it came off in the direction of regular threads. In order to keep this screwed on while the blender is spinning, it would have to turn counterclockwise, so this blender needed to be mounted on the left side of the tire. On some blenders, another way to tell the direction is that the leading edges of the blades (inside the hopper) are sharpened.
If you are using a factory rack, mount it on the back, (be sure it is a style that has a large gap where the spindle and roller can fit through), and then shim the front end of the rack up or down to make the top level.
You then need to temporarily mount a piece of plywood on the rack's top with small clips used for plumbing or wiring, and screws. You can use wood screws that are short and don't go all the way through the plywood, or metal screws that go all the way through and have a nut on the other side.  The wood screws are a little better for cleaning and wiping down the rack. Make the plywood as long as the rack top, and an inch wider than the rack on the side away from the blender, and then on the side with the blender add extra width by starting at the side of the tire that the roller touches (make sure there is air in the tire), mark the location of the side of the tire on the bottom of the plywood using a square or string with a small weight on the bottom.  Then add on outwards from that mark, the radius of the roller plus half the width of the blender plus 3/4 inch for a small edge sticking out. 
Then, while you have the plywood still attached to the rack, take the square or plumb bob, and mark the location of the rear wheel axle center on each side.
When you draw a line across the bottom of the plywood from your axle marks on each side, it will give you the front to back location of the blender spindle.  You can then figure out a mark for the side to side location based on the mark for the tire side.  Measure out from that mark the radius of the roller wheel minus 1/32", so that the roller will be lightly pressed into the tire, and mark it on the axle line.  The resulting crossmark is where the centerline of the blender spindle needs to go.
If you are making your own rack, start by measuring the outside width of the rear tangs (5 1/4" in this picture).
This is the width for the top of the new legs.  Then use 1/2 of this measurement plus an inch (for a lip) for the width of the plywood on the side away from the blender, and then add to that on the other side half the width of the tire, plus the radius of the roller, plus half the width of the blender, plus 3/4" for a small lip, to get the overall plywood top width.  To find the length, measure from the seat tube back to almost the back edge of the tire.  This will be a few inches too long, which can be trimmed off after the rest of the pieces have been fitted.
First, fit the plywood to the seat tube.  We cut a half circle in the plywood to fit the tube, then fastened a T shaped piece of sheet metal into it with a screw on each side.   We used a hose clamp to hold the bottom of the T on the seat tube.  A small ell bracket for reinforcing picture frames would probably work just as well as the T.  Don't forget- the seat tube is NOT in the center of the plywood, because the top is wider on the blender side.
 Going back to your measurements, the center of the seat tube will be in from the edge of the plywood (1/2 of the rear tang width plus the 1" for the lip) on the side away from the blender.
Next put a 2"-3" tall block (depends on where the plywood meets the seat tube best on your size bike frame) on top of the rear tire, and set the plywood on top of it.
Put a level on the plywood, and fasten the clamp on the seat tube so that the plywood is level.
 (Thumb tacked onto the wall is a piece of thread with a small weight which can be used as a plumb bob if a square won't fit under your rack for the tire and axle measurements.)
 Now you can measure down from the plywood to the back screw holes in the rear tangs, then add half an inch for the flange, to find the length of the legs.  Double Check- you may have to move the top of the legs further back to clear the roller wheel at the top of the tire.  The left and right sides should be the same length to be level, if they are different, use the average of the two.
When doing the following work you should wear safety glasses, work gloves, and ear protection, especially when using power tools.  I am going to go over this metal working part quickly, because either you know what you are doing already, or else find a local welder who can help you.
Cut two pieces of 5/16" diameter rod to the leg length (we used pieces from an old lawn leaf raker).  Then cut a piece of L angle iron (we used an old bed frame that was 2" on one side and 3" on the other) the same length as the rear tang width.   Drill several holes for screws in the angle iron side that will be against the plywood (see picture for the roller at the beginning).  Weld the rods onto the downward sides of the angle iron.  Heat up the bottom of the rods and pound a flat flange for the bolts.  Hold the leg assembly up under the plywood, and mark the location for the rear tang bolt holes on the flanges(same length both sides), then drill the holes just a little bigger than the bolt diameter.  Paint the legs or they will start to rust.  Then bolt the legs on the rear tangs (it is probably a metric thread bolt), check that you are still close to level, and put several short screws in the top angle iron holes and plywood.
The blue bike legs had to be angled backwards to clear the roller.  Now you can mark for the blender spindle, just like on the factory style rack.  Use a square or plumb bob to mark the center of the axle on each side of the bottom of the plywood, and draw a line across.  Then use the square or plumb bob to mark the roller side of the tire on the bottom of the plywood, and measure outwards from that the radius of the roller minus 1/32"  to make a cross mark on the axle line for the side to side location of the blender spindle.
With the rack in place, sit on the bike and make sure it clears your legs while pedaling, you may have to cut the front end narrower.  Once that is ok, you can take the plywood off for mounting the blender.
Attaching the blender to the rack 
You already have a cross mark on the bottom of the plywood at the location for the blender spindle,  now you need holes for screws for holding the blender in place.  The screws can simply go into the bottom of the blender case almost anywhere, but we decided to run them up into the feet to make it more secure.  Try pulling out the rubber feet, and looking in the hole.   If the hole has a top, you can screw into it.  Find coarse thread screws (sheetrock screws work well) that are just long enough to go through the plywood, rubber feet, and into the case at the top of the hole a little way.  Predrill a hole slightly smaller in diameter than the screws in each of the feet, through the rubber feet and case.
If you cannot put a screw through the feet, pick out 4 good locations near them and predrill holes in the case.
Using your modified blender (see the right column), measure from the center of the spindle to each of the predrilled holes and between the holes, and transfer these measurements over to the bottom of your plywood.  Predrill the screw holes with a drill the same size as the screws, and add a small countersink hole for the heads of the screws.  Then cut a hole for thespindle, which  can be just a little bigger than the spindle, but it works better if the hole is big enough to  fit the roller through it.
Three home workshop ways of cutting a large diameter hole are:  On the left- use a small drill for a pilot hole, then cut out the big hole with a jigsaw, Center- use a bit brace with an adjustable auger tip, Right- use a coarse tooth hole drill.
Round over all the sharp corners on the plywood, and then paint it so that you can clean it after it has become coated with sticky spilled smoothies.  After it has dried, attach the blender with the new extended shaft sticking down, to the plywood using the screws, and then attach the assembly to the bike.
The last step, fitting the roller
Depending on your tire, the roller may fit better with the rounded or the square corner up, slide it up the threaded rod for a trial.  Leave the bearings in the roller to help keep it centered on the spindle.  Then figure out the best way to fit the dished washers to the roller.  Spin two nuts up the threaded rod to above the tire tread, slide on a dished washer, the roller, the other washer, and then spin two more nuts up to the bottom of the roller.
Adjust the whole assembly up and down on the rod until it meets the tire nicely, screw the nuts in to clamp the roller between the washers, then tighten each pair of the nuts against each other so that they lock on to the shaft.  This may take a couple tries to get right.
Spin away!
An extra step you may or may not have to do
The blue bike blender had a plastic motor frame (you can see the black plastic in the next picture up), and the spindle vibrated too much and eventually bent. We straightened the spindle and added a bearing at the bottom end.
The bearing has a 1/4" center hole and a mounting flange, it was taken from an old computer printer. The bracket is another piece of the bed frame angle iron, which was held in place and scribed with a pencil, then cut out with a 4 1/2" angle grinder with a thin cutting blade.
Use Safety Gear! Heavy gloves, goggles, and long sleeves and hearing protection can prevent some nasty cuts if the cutting wheel gets pinched and breaks!
The bearing was mounted on the bracket and slipped on the spindle, the bike was laid on it's side so that gravity held the bracket in place, and then it was welded on to the rack leg. Notice that the bearing isn't even clamped onto the spindle, it only needs to stop the sideways vibration.
The orange bike has a steel motor frame, the spindle vibrates also, but it has lasted a couple years without needing the lower bearing added.
The basic recipe for one hopper full is:
2 cups frozen fruit
2 cups yogurt
2 cups milk
2 bananas
A few times we used fresh fruit, and substituted ice cream for the yogurt to make it colder. A spoonful of maple syrup can be used with tart fruit. You will learn whether to add more milk or more frozen fruit to make it thinner or thicker after a batch with your ingredients.
We have found that using ice did not work well, it only made the smoothies watery.
Bicycle Blenders in Action!
(Click on pictures to enlarge)
 The blenders have been running a marathon for the start of 2011!
There are now three blenders, we have added a regular blender running off a solar panel.  The first outing was at Hartland Farm Fest 2011, on May 29.
We had the orange bike next to the solar panel outside the tent, and the blue bike next to the solar powered blender inside the tent.
 The power starts on the left at the solar panel, and goes through the charge controller at the top, into the battery.
Then when the blender is switched on, the inverter (mounted on the white board behind the panel) converts the battery power to regular household current.  We also had a light bar filled with incandescent, compact florescent, and LED bulbs, with meter for testing how much electricity they use, running off the panel too.
Hilary Hamilton and Chuck Fenton make a batch of smoothies at Woodstock's Trek to Taste 2011, at the Marsh Billings Rockefeller National Historical Park.  The day long event promotes local food, businesses,  and benefits the Farm to School program. 
Also pedaling at Trek to Taste 2011 was teacher Linda Johanson, with a little help from students.
 The blenders started off at the Upper Valley Energy Expo on January 29, 2011, put on by the Plainfield (NH) Energy Committee.  The 7'th grade class ran them and sold the smoothies for a class fundraiser.
(Photo by Sarah Stephenson)
The small blender celebrated Earth Day on April 23, 2011 with Dartmouth students at the Earth Day Block Party, put together by the Dartmouth Office of Sustainability.
Kathryn Arion ran the blender, while other students helped pedal.  Bicycles were everywhere despite the rainy day!
Laura Simon, Katie Williams, and Chris Hoffman ran the small blender for the Transition Town WRJ's booth for Flavors of the Valley 2011, at the Hartford High school.  The event was incredibly well attended, with the school's parking lots full and cars lined up along the street.  TTWRJ tried a variation by blending an herbal tea instead of the usual thick smoothies.
Gary Band, and Jeanine Kilbride (of Cobb Hill Ice Cream) chat while pedaling just for fun!
Upper Valley Farm to School Intern Cristina Pelligrina prepares a lesson on healthy food for the students at Mt Lebanon school.
First graders from Mount Lebanon Elementary make smoothies for their school's healthy snack sale and learn about where the smoothie ingredients comes from with UVFTS intern, Cristina Pellegrini.
A Bicycle Blender in action , at Hartland Farm Fest May 31, 2009. Transition Town Hartland shared the tent with the town energy committee, the Sustainabiity Institute at Cobb Hill, and the Garden Club. It was a very "green" tent!
TTH alum Nora Foote takes a break from making smoothies to talk with Senator Bernie Sanders and Hartford High Football players at Farm Fest 2009.
Transition Town Hartland Blenders in  action at our booth for the Fourth of July Old Home Days, 2009
Our school principal, Judy Callens, and our town Manager, Bob Stacey, making smoothies at our Elementary School for National Health Week. April 4-10, 2010.  The color for the day was blue, and the smoothies were blueberry, with local milk, yogurt and maple syrup.  The 6'th grade class did most of the peddling in teams of 4, and the smoothies were enjoyed by all.
Senator Patrick Leahy and VT Secretary of Agriculture Roger Allbee announce the new Hartland Farmers Market with market manager Sharon Irwin, while Chiho Kaneko and the Conner Lee family run the blenders at the Transition Town Hartland booth in the background.
Marcelle Leahy tries out a bicycle blender at Farm Fest 2010.
A disc Jockey from KIXX radio broadcasts while making a smoothie.
Here are the bicycle blenders at Trek to Taste in Woodstock on June 5, 2010.  Helping make yogurt smoothies are Christina Marts from the Marsh Billings Rockefeller National Historical Park, Vicky Brooks from Ecofoods, and Sally Miller from Sustainable Woodstock.
Making smoothies at the Woodstock Union High School, with Kathleen Coons of the Vermont Youth Conservation Corps and the Conservation Leadership Institute program during the first week of September, 2010.
Some of the other programs discussed over smoothies at WUHS include Farm to School, local food, and community gardens. 
For more information contact Kat Coons, VYCC-National Park Learning Service Coordinator
The Bikes went traveling for 10/10/10, with the blue bike starting out at Pumpkin Fest in East Thetford, which was attended by over 1500 people.
Will Allen, farm manager of Cedar Circle Farm in East Thetford and author of War on Bugs (Chelsea Green) tries out the blender bike at Pumpkin Fest. Behind him is the bike-in project with bike tune ups and other bike information at this event.
After Will's turn, Cat Buxton, Educational Coordinator of Cedar Circle Farm, pedals the blender bike at Pumpkin Fest 10/10/10, a event.
Not to be outdone, Doug Deaett unveiled his bicycle snowplow.
The orange bike traveled to Change the World Kids in Woodstock, who held a 10/10/10 celebration on the Green.  In the background are other kids presenting 350 ppm carbon in the atmosphere information (a goal called for by many scientists), and a bicycle tuneup clinic.
Sustainable Woodstock had an information table and "carbon cutting committment tree" that the crowd looked at while waiting for the next batch of smoothies.
Change the World Kids alum Annie Leiter stopped by to visit the group.   For more information about the group, please contact
Change the World Kids
1046 Atwood Lane,
Woodstock, VT, 05091
phone (802) 457-2622
The blue bike ended up the 10/10/10 afternoon in White River Junction.  Here is Kye Cochran, general manager of the Upper Valley Food Coop, taking off for the finish line at the Transition Town White River Junction Raspberry Revolution festival, with help from Laura Simon.
The blue bicycle blender being used at Transition Town White River Junction's Summer Garden Party 2009, in Ratcliff Park , WRJ.  This advertisement was also used in the National Coop Directory for 2010.
Directions for modifying the blender
Flip the blender base upside down and look for several screws holding the top half together with the bottom.  Sometimes they are hidden under the rubber feet, which usually are just pressed in.  Separate the halves. Sometimes there are also plastic snap together tabs inside which you can pop apart with a screwdriver.  You can remove all the wiring and the motor brushes, but you will have to leave the switches  or there will be holes in the top.  The wires have copper in them and can go to metal recycling.  You should remove the power cord, so that no one does anything stupid later on.
On the left is a 1/4-20 tap, in the center are some roller skate wheels with a 1/4 inch center hole, regular nuts and a nylon insert lock nut, and on the right is a tube of thread locking compound, a 1/4" coupling nut, a short piece of 1/4" threaded rod, and two dished washers that have a 1/4" hole in the center and are wide enough to span over the bearings.  The upper dished washer is from an old record player spring mounting, the lower washer is from the rubber mount for a car shock absorber.
Modifying the easiest type of blender
Starting with the easiest type of blender, hopefully you have a fan on the bottom of the motor.  Clamp the top drive wheel with locking pliers so that it won't spin, (if you can't get a grip on the drive wheel, you should be able to wedge a piece of wood inside the motor), and unscrew the nut and remove the fan.  The thread on the end of the shaft sticking down will be a very fine pitch thread, and you need to change this to fit a 1/4-20 coupling nut from a hardware store.  Lightly oil a 1/4-20 tap and run it right over the old threads.  Proper tapping procedure is to turn 1/4 to 1/2 turn forward, and then back slightly to break the chips loose, then repeat.    Degrease the oil off the shaft with a solvent like rubbing (isopropyl) alcohol, add a drop of thread locking compound (epoxy will work too), leave off the fan and screw on the coupling nut, then add thread locking compound to a short piece (6"-8" long) of 1/4-20 threaded rod  and screw that into the other end of the coupling nut.  After it has dried, you have a shaft sticking down.  Reassemble the case, you might have to cut a hole in the bottom case for the spindle to fit through.
Modifying the top fan type of blender 
The harder situation is with the fan on top, and the motor frame encloses the bottom of the shaft.  We had this situation on the blue bike.
Here is a fan on top motor taken apart, on the left is the metal motor frame,  and the rotor on the right had the fan on the top, so there was no shaft sticking down below to tap new threads on.  We had to weld a bolt onto the bottom end of the rotor.
For this situation you will need to take the motor completely apart.  Wedge a piece of wood inside the motor so that it doesn't spin, and unscrew the drive connector on the top.  Really old blenders have a drive connector that is pressed on, avoid this type.  Remove the screws holding the motor in the top case and take out the motor, then take the motor frame apart.  You can take the electrical brushes right out.  Take a short (1"-2" long) 1/4-20 thread bolt and cut the head off, then weld it onto the bottom of the shaft.  Use electric welding, not gas, so that you don't burn up the rotor.  This does not have to be done with high precision accuracy, but you should make a jig so that it comes out very close to spinning true.  The weld will probably be lumpy,  you will have to grind it smooth so that the shaft will fit throught the bearing again.  Then take the motor frame and cut a hole in the bottom bearing housing so that the extended shaft can pass through.
This picture is from a third blender that also had the fan on the top.  Notice the weld has been ground down, and tapers from the 5/16" shaft on the left down to the 1/4" welded on bolt, so that it can fit through the bearing again.  Also, the metal motor frame bearing housing has been cut away with a hacksaw so the shaft can stick out.
After you reassemble the motor, you can attach the coupling nut and 1/4-20 threaded rod onto the bolt, similar to the easier fan on the bottom motor example above.
The underside of the blue bike's blender, with a bolt welded on the bottom of the shaft, and a hole filed through the bottom of the plastic bearing housing.
If the extended 1/4" threaded rod wobbles when you spin it with your fingers, you can lightly bend it with your hand so that the spot where the roller mounts spins true. 
TTH admin,
Dec 5, 2010, 5:49 PM