Introduction: Our Dog's $100 Recumbent Trike

Our chocolate lab, Louie, just loves to run.  His favorite used to be trotting along on a leash while I rode my bike.   But a few weeks ago an unleashed/unattended dog came at us while riding through a nearby neighborhood.  Louie instinctively bolted toward the dog and when I couldn’t release his leash quick enough, my bike went over and I took a splatter on the pavement.   The damage was minor but I became concerned it could happen again and be much worse.   So I decided to build something a little safer than my two wheeler, which turned out to be Louie’s Recumbent Trike.

I picked up two decent 20" bikes at a local flea market for $35 and purchased $65 worth of metal from a local supplier.   This included 20' of 1.5x1.5 square tubing, 12' of 1x1 square tubing, 4' of ½ x ½ square tubing, 6' of 1" black pipe and 4' of 2" wide 3/16th flat stock steel.  The remaining odds and ends for the project (nuts, bolts, upholstery material and primer) were things I had in my shop and would probably add up to about $10 or $15 if they had to be purchased.

I would rate this project as “moderately difficult” since it requires a good bit of welding as well as cutting and shaping some metal parts.  It may also require some design work since the old bikes you find to make your trike might be quite different from the ones I happened to get.  You also need a basic understanding how a bike is assembled and taken apart as well as a decent grasp of how a derailleur works and how it is adjusted.   Most of this information can be found on the web if you lack hands-on experience.  Derailleurs were a mystery to me when I started this project.  So thank you internet.

Step 1: Front Wheel and Steering

I opted for a “delta” design, single front wheel to do the steering and dual rear wheels.   I am also a big fan of trike builder Bill Irvine (google “bill irvine trikes” to see some of his work) who builds trikes with front wheel power trains - pedals and chain drive go to the front wheel.  For a first time builder, I found this design to be the simplest and most economical.  Note, however, that this design also results in some "pedal steer" and takes a bit of getting used to when first riding.

I began with this Huffy Roadmaster 20" frame and 6 speed sprocket set.  (Photo 1)   I used a 4" angle grinder to cut away unneeded pieces of the frame.  (Photo  2)   Next I marked and cut a “birds mouth” in the seat tube so that the tube will point forward 18 degrees from vertical rather than to the rear as it did originally. (Photo 3) The seat tube is then bent forward and welded.  (Photo 4)  The seat tube is strengthened with a steel gusset.  I first made a patten using heavy paper (Photo 5) and then cut the gusset from 1/8" flat stock and welded it in place.  (Photo 5)   Cut off the balance of the lower support bar.  (Photo 7)

The steering head is cut away from the down tube.  (Photo 8) Cut a length of 1.5 x 1.5 square tubing one inch shorter than the head tube.  (Photo 9).   Cut away one of the four sides of the square tubing making it into a U-shaped channel.  (Photo 10).   Fit the channel around the head tube.  (Photo 11) and weld it in place filling in the gaps on the top and the bottom with small pieces of flat stock.  (Photo 12)

Cut the top portion of the steering tube away from the front fork assembly.  (Photo 13)   Remove the seat post from the saddle.  Butt weld the seat post to the steering tube.  Make sure the tube and post are straight and aligned by inserting appropriately sized tubing into the inside of the tube and post.  I used a 13 mm socket to slide inside the steering tube and then found a leftover length of thin wall tubing from a solar light set which slipped inside the seat post tube AND fit snuggly over the 13 mm socket.   (Photo 14)    These parts are clamped together to hold them tight and straight and then the butt joint is welded (note: the 13 mm socket is sacrificed to the cause).  (Photo 15)   Cut away the remaining “ears” of the fork attachment points.  (Photo 16)    This is now the new steering tube.  (Photo 17)

Step 2: Main Frame

Cut 1.5 x 1.5 square tubing for the main frame.   I used a 120 degree angle at the top and bottom of the vertical and an 18 degree angle to mount the head tube to the main frame.  The top stub is about 4" long.   The angled vertical tube is about 15" and the bottom tube is 27".   (Photo 1) None of these measurements are etched in stone.   To keep things square and in place for welding use two pieces of 2x4 cut to exactly the same length (for this trike, 13") to keep the lower tube and upper tube parallel.  Then clamp the parts together and weld.  (Photo 2) Weld the head tube assembly to the top stub of the main frame.  (Photo 3)

Step 3: Front Forks

Temporarily assemble the front wheel and steering tube to the main frame.  (Photo 1) Note that  with the drive sprockets now on the front rather than the rear, the ratcheting mechanism requires that the sprocket set must be reversed (the wheel needs to be turned 180* in the drop outs)  This also requires that the pedals be installed in the reverse position so that the pedal sprocket is on the same side as the drive wheel cog set.  As will be shown later, the derailleur must also be turned upside down.

The front forks are attached to the existing mounting holes from the Huffy.  (Photo 2) Cut a 1 ½" x 2" piece of 3/16 flat stock, drill holes to match the mounting points and screw the flat stock to the drop out.  (Photo 3)   Cut a slit in the end of a 3' section of 1" black pipe and place it over the flat stock.  (Photo 4)    Drill a 3/8" hole through the steering stem.  (Photo 5) Put the stem in place in the steering tube.   Line up the top end of the black pipe with this hole in the stem and then tack weld the bottom of the black pipe to the flat stock mounting tab.  Remove the black pipe and finish welding the mounting tabs.   Cut off any excess portions of the 3/16 flat stock. (Photo 6)

Attach the lower end of the black pipe to the drop out and then drill a 3/8" hole in the top end of the black pipe to match the hole through the steering stem.   Use a bolt or threaded rod to secure the top end of the black pipe to the steering stem.  (Photo 7)   The front forks are now complete.  (Photo 8)

Step 4: Rear Frame

Cut 2 pieces of 1.5" square tubing at 30" and 4 pieces at 21" and weld them as shown.  (Photo 1)   Cut four “drop outs”, 4" long, from 2" wide 3/16" flat stock.   Drill matching holes in each of the four drop outs.  The holes should be the diameter of your axles.  (Photo 2)   Using an angle grinder, cut open each of the drop outs making them slightly wider at the mouth.  (Photo 3).   Line up the drop outs using a wheel and axle as a guide (Photo 4) and weld the drop outs in place.  (Photo 5)   The trike can now sit on its own three feet.  (Photo 6 and 7)

Step 5: Brakes

Cut the front brake bracket away from the rest of the front fork.  (Photo 1)  Cut two mounting plates from 3/16" flat stock.  (Photo 2)   Drill holes and attach the mounting plates to the brake bracket.  (Photo 3)   Position the brakes and weld the mounting plates to the front forks.  (Photo  4 and 5)

Cable guides for brakes and derailleurs can be purchased but you can also make your own using #10-24 x 3/4" coupling nuts from Home Depot.  (Photo 6)   Clamp the nut in a drill press vise and bore out one end large enough for the ferrule.   The bit should only go about  ½" deep into the nut leaving enough metal at the bottom or the nut to prevent the ferrule from slipping through.  (Photo 7)    Put the nut in a vise and slit it lengthwise with a 4" angle grinder.  (Photo 8 and 9)

Step 6: Derailleur

The derailleur must be installed upside down in order to operate properly. The mounting point must also be moved 2 1/4" forward and about 1/16" higher than the original axle mounting point. A bracket to do this is made by welding together two pieces of 3/16" flat stock. (Photo 1) Holes are drilled to mount the bracket on the axle and to mount the derailleur to the bracket. Note the smaller hole which is used to keep the derailleur from spinning out of position. (Photo 2) The bracket is mounted on the axle (photo 3) and the derailleur is attached (Photo 4)

Step 7: Adjustable Recumbent Seat

The metal frame for the seat is made in three separate sections allowing for full adjustment of the back position and the headrest position.   The seat frame is made of 1" square tubing.  The bottom and top sections are 10" long and 9.5" wide.   The longer middle section is 19" long and 9.5" wide.  (Photo 1)   The cushions which cover the frame are 12" wide.   The top and bottom cushions are 11" long while the middle section is 17" long.

The sections are “hinged” to each other by welding 1"x2" pieces of 3/16" flat stock to the outside of the frame rails for the top and bottom section of the seat.  The hinges extend toward the center section of the seat and holes are drilled through the hinge section and the side rails of the seats center section. (Photo 2)  The sections are then bolted together.  (Photo 3 and 4)   The seat sections can be moved to an unlimited number of positions relative to each other and then the hinge bolts can be tightened to hold the seat in place.  (Photo 5)   Addition support for the seat is provided by two small braces on the back side of the seat which are also fully adjustable.  (Photo 6)

The seat cushions are made using ½" strand board as a base.  (Photo 7) Holes are drilled through the metal frame and wooden seat base and tee nuts (Photo 8) are used to secure the seat base.  (Photo 9)  To secure the seat to the main frame of the trike, metal tabs are welded to the bottom of the seat frame and holes are drilled through the tabs.  (Photo 10)   The seat frame is flipped over and can be slid forward and backward along the center rib of the trike’s main frame.  When a comfortable pedaling position is found, the seat bolts are tightened in place.  (Photo 11)

The cushion padding consists of 4 layers of 1/4" closed cell foam glued together on top of the wooden seat base.  The edges of the foam and base are sanded to provide a smooth and even surface.  (Photo 12)   The upholstery for each seat section consists of three pieces.  The seat top, the seat side, and a strip of welting.  (Photo 13) The three pieces are sewn together inside out.  (Photo 14) The upholstery is then turned right-side-out, stretched over the foam, and stapled to the bottom of the wooden seat base.  (Photo 15)

Step 8: Ready to Ride.

The finished trike (Photo 1 and 2) Also a short video of Louie taking an early cruise.

The trike has been on the road for a number of months. In fact, Louie has lost about 10 lbs due in part to the great exercise he gets running along with the trike. I recently tore the trike down, however, to apply a paint job AND to install an electric motor. The Instructable for making the trike electric (dual powered) can be seen here.