Thunder Cruise - a 2 Wheel Recumbent Bike Project

Introduction: Thunder Cruise - a 2 Wheel Recumbent Bike Project

Due to the 2020 pandemic it was difficult to travel. Instead of a beach holiday, or a mountain holiday we decided to rather spend the time with parents, and as we were separated, and could not visit them for a prolonged period, once there was a window of opportunity, we decided to make our visit count. We aligned about the details ahead, and spent an entire week, working on and off - on our recumbent project. The first step was to visualize the desired outcome. The picture attached was created in photoshop. And the photo next to it shows the result of our 1 week work. Pretty accurate isn't it? If you are interested and would like to follow further developments you can also peak into our channel with interesting Recumbent Bikes related videos: https://joinmy.site/DU7BA6 . Be advised, I put an IP tracker on the link. This will collect high level data, like which countries and regions are most interested in my videos. Nothing harmful, but you are advised not to click on link if you value your privacy more than what you could learn from the videos.

Step 1:

Our goal was to make a recumbent without any welding. This could be easiest achieved by using existing bikes and bike frames. The first thing was therefore to identify the donor bikes and how they would fit together. The yellow frame of a cruise bike was chosen as it had a large space between the steering tube and the seat post. Ideal for all kind of experimenting and installations. The donor bike was a fully suspended mountain bike. (Cheap and made in Asia, so it was not very safe to begin with and destined for DIY haha!). One of the pictures shows an earlier attempt, where the mountain bike would have been the main frame. Due to safety issues we abandoned that idea fairly quickly. Can you guess why?

Step 2:

By the time night set in we had frame with two tires and a salvaged rare suspension. First of all, the rare fork had to be shrunk, as it was receiving a front tire with a narrow axle. The front fork in turn had to be widened to accommodate the entire cassette of the rear tire. The fork manipulation is a real challenge. We used a 30 cm long nut with bolts and tensed the fork with pliers first. When the nut started to bend under pressure we switched to a car-lift (car-jack). Using a car jack is tricky, my dad volunteered and managed to widen the fork but unfortunately only one branch was bent and the frame became crooked. Careful corrections had to be made. This is really delicate, as depending on the strength of your frame it may crack or break under frequent or sudden pressure differences. As I took over at this step we were lucky and managed to salvage the situation. Once the forks were done we could insert the wheels. The rear wheel of the mountain bike together with entire shifter and breaks was installed as front wheel into the cruise bike's front fork. This is usually done by cutting and welding, we managed to fit both forks onto the main axle. The cruise bike's forks were bulging from the inner side. The bulges had to be grinded down nevertheless.

Step 3:

The next morning we turned the entire house upside down as we searched for the old childhood skate-boards. The wooden board was decided to be quick and cheap alternative for the resin reinforced glass fiber seats. (I actually made one, but my dad insisted it will be safer if we just use a hard plywood board). An hour later my mom got curious about what was going on. As we told her she confessed the skateboard was thrown away a long time ago. So we spent that day searching for second hand and junk-yard skateboards... After having no luck we decided to buy one. This became the most expensive component of the final cruise bike, haha! And we failed in our attempt of keeping the build weld-free. The support structure of the seat actually had to be arc-welded. The metal rod supporting the seat was bent, welded and the skateboard was cut and screwed-on at an angle. The wooden board was screwed back using the screws and holes made for the skateboard-tire mechanism. So we managed to keep the integrity of the board stable. The more difficult part was attaching the seat-mechanism onto the bike. The spring-suspension kept the seat too wobbly, so we ended up fixing the seat to the seat-post - rendering the spring useless. The front of the seat mechanism was drilled into the bike's frame and attached using a door hinge, which was originally intended to allow for the spring-suspension to suspend the seat. At last, we bent and formed a metal rod headrest holder.

Step 4:

The bike was then transported abroad and I continued working on the seat independently. The most convenient approach was to use hardened foam from the hardware store, cut it up and glue it on to the skate board using duck tape. The headrest was also made out of hardened foam. The entire seat was then covered with a car seat cover. I hammered on eyelets all along the seat cover's circumference and used them along with reinforced rope to bootstrap the car seat cover enveloping the seat.

Step 5:

The next problem I discovered was the gears over the front wheel were shifting the weight of the bike to the front and it was very difficult to steer and even to hold balance. So next I invented two spring mechanisms to reinforce the front wheel. These kept the wheel in balance and made steering much easier. I can not recommend it enough. Please always use spring stabilization on front drive recumbents. It makes the ride so much more enjoyable.

Step 6:

I forgot to mention, that the pedals over the front wheel had to be mounted to the steering rod of under the handle bars. This was accomplished with screws. The steering rod therefore squeaks every time the pedals are under pressure. We also replaced the steering for monkey-bars. They provided for the required clearance for the upper thighs. Also, it has to be mentioned, learning how to ride one of these things takes almost as long as learning how to ride a bike for the first time. haha!

Step 7:

I was just an occasional biker, but since we built the recumbent I take it out every week, even ride it to the grocery store. Even in the winter. (Put on the ski cloths, warm boots, a facemask is nowadays also not weird and keeps your face nicely warm. Gloves are also essential for winter riding.) It is so much fun! I love this baby and can not recommend it enough! If you would have some questions, recommendations or proposals you can reach out to me here: petera_sha@yahoo.com.hk

Happy cruising!

Cheers!

1 Person Made This Project!

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2 Comments

0
seamster
seamster

1 year ago

Nice! I love the skateboard deck as the seat. Very clever! : )

0
petera_SHA
petera_SHA

Reply 1 year ago

thanx, was probably the most expensive component on the entire build, haha!