Recumbent Tadpole

I need to put my Cannondale recumbent bike on the web site but this is how I got started riding other alternative bikes over the years. I had a good amateur radio friend Ron Erxleben W0IFL he got me to go riding with him. He had a Bike E that was built in the US. It was a recumbent with a 20 inch back tire and a 16 inch on the front. He had two of them so he let me use one. He had bought it for his wife and she did not ride it. So I rode it all summer and decide that I would buy one for my 50th birthday. So I put one on order and come to find out they went out of business that same week! So I was not going to get a new Bike E. The bike dealer that order my Bike E also sold Cannondale's. Come to find out Cannondale had just released a new recumbent called EasyRider. It was really superior bike compared to the Bike E. The dealer let me have it for the same price that I was going to get the Bike E for. I have ridden it for about 8 years and put about seven thousand miles on it. I have been extremely happy with it but they no longer build it either. But if anything would ever break except the frame, I could replace most of it with after market parts.

Getting back to the tadpole, I have seen multiple drawings of tadpole built on the Internet. I also was searching and found a set of books called the evil genius series. They had a bike builder one that I asked for Christmas two years ago. The author is quite a good designer and built some outrageous machines. One that caught my eye was a recumbent built out of square tubing.

In the winter months I normally do not work at the bike shop. So I really have a lot of time on my hands. I decided that I could build that recumbent so I started on it. First I decided that I would use my new book to build the frame. I really did not want to buy new tubing for frame but the author kept repeating that you would never get the frame straight. I also had another friend here in town that built his own and did use round tubing. So with that in mind I decide to use some old tubing that I had here. You will ask where did that tubing come from? Well, my wife had a old swing set that the bottom of the seat had rotted. So the swing frame was still in pretty good shape. I started to cut it up and here is what it looked like:

I knew I need to get the frame straight so I found every straight edge that I had around the house. The frame was so long that I felt like I could use a longer straight edge so I went to Sears and bought a drywall square. As you can see from the following picture I picked up a couple of junk bikes from the shop that people had left and did not want to fix. I also had in the work of progress that I would not buy anything for the tadpole and use all used parts! I really did not know how it would turn out. Here is a picture of the start of building the frame. If you notice I used the back frame from a Wal-mart bike that had full suspension. I had never seen a tadpole with suspension except in my new book.

This is the start of cross boom section for the steering. Using the Ackerman steering concept here is a picture of the kingpin build and steering drawings

As you can see in the next picture I need to weld the cross frame boom for the steering. It needs to be tilted back 12 deg's for the caster angle.

I have jumped ahead and as you can see in the next two pictures I built the headsets and mounted the wheels:

The next thing that I worked on was how I would mount brakes on both front wheels. From my readings putting brakes on the rear wheel does not do much good because your weight is on the two front tires. So the rear tire would just slide when applying the brakes. I am going to use some old style 10 speed brakes. Plus I need to be able to change a tire by taking off of the brake easily. Here are pictures of the build process

I started to build the steering, the tie rods and tie rod ends. Here are pictures of the build process:

This is the start of the seat build. I did not like the one that was in the Evil Genius book. I did find one that I liked on the internet. It was a sling seat, I used conduit benders on some of the smaller diameter pipe that came from the swing frame. It really worked out well, here is some pictures of the build:

My wife Gail helped me to build the seat. We bought the material at Joan's Fabric store, it was Duck cloth. As you can see from the pictures we made it wider and longer than the seat. She sewed a small seam on the long part of the fabric and I put long rods on each side. I then punched holes to lace twine like a tying a shoe. I had read articles from guy's that had tried to set grommets in the fabric. The grommets tended to pull out of the fabric.

I should have taken more pictures of the build process but here is the completed project. A few notes, I used a top of a fence post to attach the crank and it slips in and out of the main frame. This allows you to adjusted the bike for a shorter or taller rider. The bikes seat is also adjustable. I used roller blade wheels to help guide the chain. The chain is also guided through black yard sprinkler pipe. That way it does not rub on the bottom of the seat. To flare the ends of the black pipe I heated them with a heat gun and forced the ends on a ball peen hammer. It took three bike chains to reach the back of the bike. I used a longer pipe on the crank assembly to hold a water bottle, computer and GPS. I am wanting to change the crank at some point to a 3 piece crank and not the old one I have on it now. I have ridden this bike about 300 miles this summer and have really enjoyed it. I hooked a trailer up to it to ride my grand daughter. Hope you enjoy also: