Design Review Report: Swing Bike

As I said in my design inspiration post, I plan on building a swing bike. A swing bike is a bike with an extra pivot on the seat tube, which allows the front and rear wheels to steer independently of each other thus opening up a dimension of agility and fun that normal bicycles can’t match.

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Normally, the first instinct when designing a bike is to make it as racy and futuristic looking as possible, since most of the revenue generated in cycling comes from racing. Things like lots of carbon fiber, deep dish aerodynamic wheels, and electronic drivetrains come to mind. However, this swing bike isn’t designed to be raced; it’s designed for fun, old school fun. You’re supposed to be twisting and curving on the road and enjoying how fun it feels, not killing yourself going full gas to go as fast as possible. Therefore I will be applying a much more carefree aesthetic to it. My plan is to make it a bit raw: I might take cans of spray paint to it and splatter the whole frame with a huge range of colors. Make it my own, something that’s not easily replicated. The idea is to make the bike seem like an instrument of fun and light-heartedness upon first impression.

This swing bike will operate like a normal bicycle, except with the seat tube pivot it will be able to swing all over the road. It will lend this machine agility that cannot be achieved on a normal bike: for example, you could ride in a circle with a small radius, with the wheels in different planes, and make much tighter turns than usual. A bike like this may not be the fastest or be the best option for climbing, but it’s just fine for cruising around town and having a good time. There are events such as the Tour de Fat in Ft. Collins or the Thursday night Cruiser ride during the summertime in Boulder where the swing bike will fit right in as well. Even amongst the crazy costumes and bikes you’ll find at these rides, the uniqueness (and likely bright colors) of the swing bike will still stand out.

While I have seen a few people online make their own swing bikes, they often stop once it’s functional and it’s left looking like a welded piece of scrap. I intend to make my bike a more finished looking product by applying an aesthetic via a paint job. I got this idea from a company called Squid Bikes, who sell frames unpainted to their customers so they can take a spray paint rattlecan to it and customize it however they like. There are also a couple other creative elements that I could implement to differentiate my bike from the rest. I could weld the bike so that it resembles a chopper for a motorcycle aesthetic, although whether I have the budget and time to do that remains to be seen.  I could also see if I could design a robust locking/unlocking mechanism for the seat tube pivot for if you want the bike to function as a normal bike. I will decide on these later in the design process.

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Someone’s finished Squid frame, custom painted the way they like it.

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A Squid bike frame. They are sold unpainted.

 

 

 

 

 

 

 

 

 

 

I think the trickiest part of this project will be making sure the bike frame is strong and won’t collapse when you actually ride it is essential. I have consulted someone I know who welds for input on how difficult welding a bike frame would be, and while he said it isn’t a very hard project I haven’t welded anything of this nature before. Modeling the frame in Solidworks and making sure it’s a good structure will be essential.

I don’t know if I’d be able to create a prototype. Welding a frame takes quite a bit of time, more so than I think I’d have time for in this project. Also, the cost of finding old bikes to cut apart is significant as well. However, I don’t think a prototype is as necessary for this project as it may be for others. There are other examples of swing bikes online and most of them follow a similar build, so as long as I keep my build of a similar nature it shouldn’t fail. Yes, I know I should be trying to add my own twist to the concept. I plan to instead differentiate my design through visual aesthetics and touches that enhance its functionality and not through actual structure. But I believe that modeling my design in Solidworks should be a sufficient “prototype,” since it’s a lot cheaper and easier to do and I can edit my design without having to re-build another prototype.

This project shouldn’t cost much for me. Swing bikes require two junk bikes and welding materials. I already have two junk bikes that I can use, and I have access to welding equipment both through the school and through friends. For the rest of the bike, I have tons of unused bike parts lying around the house that I can utilize. The only costs that I should need to account for are for taking a welding class in the idea forge, for whatever materials I need to finish and paint the frame, and for creating the locking mechanism for the seat pivot.

  • Welding class (maybe): $200
  • Paint/paint stripper/clearcoat: $50ish
  • Bikes: Free
  • Welding equipment: Use ITLL or friends
  • Bike parts: already have ’em

Scheduling is tentative, but I plan to set aside even chunks of the next two months for 3 separate parts: design (Solidworks, maybe engineering the seat pivot locking mechanism), fabrication (welding), and decoration (painting, customizing, putting the bike together). This is all subject to change.

  • March 2-March 18: Design
  • March 16: Welding class at Idea Forge.
  • March 28-April 8: Fabrication
  • April 9-end of semester: decoration

Here’s a video to give you an idea of what swing bikes are all about:

https://www.youtube.com/watch?v=NYpjXztfrhM

Photo credits: squidbikes.com

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6 Comments. Leave new

Shawn Sprinkle
March 7, 2016 5:03 pm

This will definitely give you the opportunity to weld! If you need to manufacture some parts and need help let me know, I’ve done a decent amount of machining this semester for senior design. Can’t wait to see the final product!

Reply

I have seen this bike before on one of the Thursday night bike rides, it’s such a great idea. Check the Thursday night bike rides to see those people if you need. I love the project and glad to hear that you are planning on having a lock to it so it functions as a normal bike.

Reply

A locking mechanism would be great. It would really make the bike dynamic and user customizable. The project idea is really cool, and something I have never seen before. Starting with a bare frame would be a great starting point as a blank canvas for your design. This project seems fairly advanced in the manufacturing. Do you have experience welding? Will you do engineering calculations to make sure that the bike will be safe to ride? Adding lights would be awesome as well. Cool project.

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Samantha Maierhofer
March 7, 2016 12:33 pm

Really cool idea and excited to see the end result. It seems like it might be a pretty ambitious project. Are you worried about getting everything completed before the end of the semester?

Reply
Meridith Richter
March 7, 2016 12:32 pm

I love the idea – what is your ideal concept for the final aesthetic of the bike, color, style, etc? Can’t wait to see it!

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Brendan Warren
March 6, 2016 11:46 pm

This project is going to be sweet! I agree that the bike will fit right in on the Thursday night rides in Boulder. Have you considered putting lights or bells on it to compliment that evening event? I’m excited to see it come to life!

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