Building large trike and would like some insight

[zensurfer]

This will be my third burn this year and I wanted to build a large trike.

I was wondering if people with more experience could help me in avoiding any pitfalls on my journey.

Sketches will be uploaded after I get some more questions finished.

First some insight in my plans then questions about bike designs.


I want to build a trike that is powered by two people and capable of carrying at least two others. I want a wide space in the middle with netting to allow the passenger to lay down and "float" over the playa while moving.

What is the most efficient setup with the wheels and the drive train?
-Should I have two wheels in back that are powered and drive with the front one. Or should I have one wheel steering in back and two front wheels powered. I have seen many awesome ones using the two front wheels powered.

-How big of wheels would be needed to carry 4 people but only be powered by 2? Should I aim for all tires to be same size or mix and match alright? Inflated tires or just wide rims?

-I know nothing of bike part prices, how much in raw materials would this project cost (rough estimate)? Under 500? Under 800?

-What parts of bicycles could I use Frankenstein style for my project?

-Is there websites out there that would be helpful in my endeavor?

-Any advice on designs to stay away from?


Thanks for any advice you can provide.

[motskyroonmatick]

http://kinetickingdom.com/KK-how2/index.html

[LeChatNoir]

Hi zensurfer,

This is a big broad thing you're asking about. If you're totally green to it, take the time to examine as many bike and trike designs as you can. Scour the net and see what you can dig up. The Kinetic Sculpture folks have a wealth of knowledge to learn from.

For flat places like the playa, bigger diameter wheels work nicely... less rolling resistance. Give yourself a range of gears, but be sure to have some real low one so it's easier to pedal. This sounds fairly large and large things get harder to move when the wind is blowing right at you.

Hang around and post some pics of your ideas. There's lots of folks here who'll help out, especially if you're putting your heart into it.

[Captain Goddammit]

Yep The Cat is right, wide range of gears including some extremely low ones is a must with any big human-powered vehicle on the soft playa.

I think for simplicity, important since you say this stuff is new to you, I'd lean toward a single front wheel that steers, with power to the rear wheels. Setting up good steering for a pair of front wheels would be much more involved (start by Googling the term "ackerman angle").
Sending power via chain to non-steering rear wheels is simple too, but you'll need to use a differential between the rear wheels rather than just a solid axle linking them together or it'll be hard to turn when you have passengers aboard.

[LeChatNoir]

Perhaps an old pedal trike could be cut apart and reassembled on a new, larger frame?

How’s your welding skills, zensurfer?

Here's an excellent trike creation for you to check out for inspiration

Further info on some really cool pedal-powered creations:

http://krankboomclank.com/

[Tiahaar]

also some neat bike/trike/quad creations, galleries, and plans here at http://www.atomiczombie.com/

[Elliot]

http://kinetickingdom.com/KK-how2/index.html

Wow, my 15 minutes of fame!

The Captain is right, but you can also skip the differential by letting each rider drive one wheel, with no drive-connection between the two.

As has already been mentioned, you are biting over a lot with a fairly small mouth (lack of engineering and fabricating experience). So your top priority right now is to learn.

My first trike (below) was not built overnight!



You are getting great advice from the others, so I'll shush up now.

[zensurfer]

@LeChatNoir - Is there a limit to returns of having large wheels. Is a 4ft wheel going to be a lot easier to get moving vs a 2ft wheel? How bout the 8ft vs 4ft? Those wheels are AWESOME? I wonder how much those cost to build? It's hard to figure out how they used plastic storm drain material to get that outter wheel. Did they melt it together?

@Captain Godddammit and LeChatNoir - Where are good places to get gears for this trike? Can I use bicycle gears? Or should I buy new ones online? Are their best practices in what ratio of gears people have used? I was aiming for two people peddling and have 2-3 extra people enjoying the ride? is this too ambitious or just need lower gears and bigger wheels?


What is the difference in putting my single steering wheel in the front vs the back? Reading the kinetic kingdom article it talks about I would need a differential if I use a solid axle

"What does not work is a solid axle -- forcing both drive wheels to turn at the same speed. You would not be able to turn. Been tried. Doesn't work. "

What should we finalize first? wheels? frame? or drive system?

Is it worth it to build off of old biycles or use new materials? Does anyone have favorite new material to use (steel tubing, electrical conduit, aluminum, ... etc)?

I was very inspired last year by the giant wheels that had a working ferris wheels inside. It was made by a heart surgeon, ai professor, and an artist. Our team for our project is software engineer, mechanical engineer, and physicist/beer brewer.

I just got back from Asia and ready to go full speed to get this done.

Thanks for all of the support and help so far.

[LeChatNoir]

Bigger wheels have less rolling resistance, especially in bumpy or soft terrain. Think pulling a small wheel dolly through sand verses a larger pneumatic wheeled one. But they can require more power to move at a given speed compared to smaller ones. The thing to remember though is that you have to have lower gears for bigger wheels, since they cover more ground with one revolution than small wheels. The bigger the wheel, the lower the gear. The circumference of your wheel is the ground you will cover with one revolution. From there you can figure your drive train out by knowing your comfortable cadnece at the pedals and the mph you wish to go. Obviously bikes and reach pretty good speeds on the flat playa, but I’d suggest for transporting people you don’t try to go faster than 5 mph. Slower, but easier with a load. Your team mechanical engineer should be able to help with the ratios.

Unless you have an affinity and direct desire to reuse old rusty junk, like me, I’d definitely chop up old bikes for parts. Easy to find and all parts of the drive train are easy to couple together. Elliot or the other Kinetic Racing pros could better advise you on bike parts than I.

[LeChatNoir]

Those wheels are AWESOME? I wonder how much those cost to build? It's hard to figure out how they used plastic storm drain material to get that outter wheel. Did they melt it together?

They just cut two-ring sections of the appropriate sized drain pipe. In their case, very large. I'm honestly not even sure where to find it that big around my part of the country, though I'm sure it's a lot to do with knowing the right people in the right sector of the construction industry.

[theCryptofishist]

Bigger wheels have less rolling resistance, especially in bumpy or soft terrain. Think pulling a small wheel dolly through sand verses a larger pneumatic wheeled one. But they can require more power to move at a given speed compared to smaller ones.

I knew about that bigger wheel thing. That's why I have 8 inchers instead of 6s. And that power thing makes sense of something I never wondered about--why my power chair wheels are smaller than the push chair.
One other thing I know; smaller wheels make tighter turns.

[zensurfer]

I just got back from talking to a bike shop and a steel warehouse.

Bike shop confirmed most of my design ideas, but I was still unsure on the frame materials.

Went to the steel place, which was really helpful and gave me quotes on different widths and thickness of welding steel tubes. The two sizes he gave are 1.5" width 16 gauge and 1.5" width 13 gauge at $1.26/ft and $1.82/ft.

Also there was 6601 alloy aluminum 1.5" width 1/8" wall.

Can anyone give their opinions on building frames with any of these materials and tips or tricks with working with them to build a frame.

Now we need to find someone to teach us welding and figure out how to rent/borrow welding equipment.

After working out exact measurements and design on paper we will buy the pipes and get them cut there and weld those pipes together and then focus on fun drive mechanism and shade structure.