Instructables

Build a kid's long-wheelbase low racer recumbent bicycle

Featured
This is a companion piece to my other instructable on building a low racer recumbent. My oldest kid likes to ride bikes, too, and had to have a racer to match mine. It was a much easier build and I'm very pleased with the results.

 
Remove these adsRemove these ads by Signing Up

Step 1: Materials and Tools

Materials:
  • One whole kid's BMX-style bike with 16" wheels
  • The steering tube and steering components from another bike (or some ingenuity)
  • One length of 1" EMT electrical conduit (around $7 for 10')
  • One length of 3/4" EMT electrical conduit (around $5 for 10')
  • A couple of feet of 1" x 3/32" mild steel or some other stout steel for brackets
  • Enough 1/2" - 3/4" plywood to fit your kid's back and posterior
  • Miscellaneous nuts, bolts and screws
  • Optional: An old 3-speed bike for the rear hub, front sprocket, and chain guard

Tools:
  • Flux core welder, welding gloves, tip dip, wire brush, chipping hammer
  • Various clamps
  • Angle grinder with cutoff/grit/wire wheels
  • Bench grinder with cutoff/grit/wire wheels
  • Hack saw
  • Bike assembly tools
  • Woodworking tools (to cut out and shape the seat)
  • Files/rasps

You will also need a positive attitude, patience, creative thinking. If you have a child helping, please use common sense and pay extra attention to safety. Explain what you intend to do, why it is unsafe and what you are doing to make it safer. Make this a fun learning experience, not a trip to the hospital.

Step 2: Disassemble and Cut Frame

Picture of Disassemble and Cut Frame
Strip your donor bike down.

If you are careful with the source bike you select, you should only have to cut the frame in three places.
*where the top-tube hits the seat tube
*where the bottom bracket and chain stays intersect
*where the seat tube and the bottom bracket intersect

If your donor bike top tube doesn't match up with the 3/4" conduit well, you will just want to remove the top tube entirely and replace it. Try to avoid this as it makes things trickier.
1-40 of 68Next »
AronC081611 months ago
If you want to buy "tie rod ends" from your local specialty hardware store you are going to want to ask for "heim joints"

Great instructable by the way I love it!
davec86563 years ago
hey Homba, love the build. I'm getting stuff together to build one and was wondering if any major differences using a 20" kids bike instead of 16". I have parts of a 20" left from my first build.
for the steering i would have just cut the frame and re welded it so alls you need is a longer peace of pipe
This has inspired me to at least try to build a recumbent unicycle. Now that would look cool cruising down the street.
japanbiker4 years ago
Bellisima!
 Thanks much for sharing this and your other plans.  Both look great.  I'll be using your plans as inspiration to build my first recumbent.  Thanks again.
sayoian995 years ago
can you mass produce those?PWWEEEESE?
homba (author)  sayoian995 years ago
I wish I could - not enough used bikes for raw materials laying around. If you can get a hold of a bike and borrow/beg a welder, you should try a build - this is not a difficult project. There's only 5 welds or so on the frame and 4 welds for the seat brackets. Everything else can be done with simple hand tools (hacksaw, files, etc) and a drill. A grinder and wire wheel attachment would help, but is only a time-saver.
sayoian99 homba5 years ago
is it possible w/o welds,and on a budget?
homba (author)  sayoian995 years ago
Budget - definitely ... scrounge bikes from the trash, EMT tubing is well under $10, and a can of primer and a can of paint is cheap. The most expensive items would be the tie rod ends and a die to cut threads (but you could probably just buy threaded rod cheap) No Welder - maybe ... you might be able to do some clever bolting, but it won't be very strong and might be dangerous. A welder can be pricey unless you're clever and a little risky and build one of the frightening 'ible welders. I would get everything cut out, cleaned up, and ready to weld and see if you can nicely ask your local school or trade college if the students could weld it for you. I've had some success with that in the past. Pizza and a couple of 2-liters of soda are usually appreciated. Do you have an uncle or brother-in-law or a co-worker that you can beg to weld it? Offer to scrounge an cut out a frame for him/her if they will do the welding. I've done that before to get access to a tool I couldn't afford. If you give it a lot of thought, I bet you can come up with a solution. My uncle has tons of tools (he used to own an auto-repair shop), so I would often bring over lunch to get access to a tool I needed. He'd often get interested and help out, too. If you put it out there, you might even find someone on the site that lives close that would be kind enough to help out. You can do it! Just get into that creatively-cheap-a$$ mindset and come up with a solution to your lack of resources - trash picking, thrift store-ing, scrounging, and bartering are great skills to develop and have :)
sayoian99 homba5 years ago
well,the idea for my bike that im making is more like the one shown http://www.instructables.com/id/Front_Wheel_Drive_Center_Steer_Semi_Recumbent_Bicy/
homba (author)  sayoian995 years ago
I've seen that one - I say go for it. Front wheel drive is odd at first, but you get used to it quick. Good Luck!
sayoian99 homba5 years ago
do you know where i can get a 20" bike for about $10-$20?(for front wheel drive.)
homba (author)  sayoian995 years ago
I always either do thrift store or trash pick ... if you put it out there to neighbors and relatives that you are looking for free junk bikes, that will often work. You might not get exactly the bike you are looking for, but I bet you'll end up with more old bikes than you can use (I've had that happen in years past). At this point, I find mostly 80's era 10 speed road bikes, crappy walmart/target "Magna" brand pieces of junk, 16" kid's bikes, and 20" bmx bikes. I use the 10 speeds if they are good quality, strip the magnas for parts if they are any good, use the 16" and 20" for stuff for my kids and recycle what's left over. Having said that, it's been around 2 years since I've done any bike building. My kids are growing out of what we currently have, so next spring may be the time to start up again.
sayoian99 homba5 years ago
well,what frame materials do i need,i think one of my neighbors(lots of tools with him,you should see his garage...)has a welding tool(im not 100% sure...) that i might be able to get help with...
homba (author)  sayoian995 years ago
You need EMT from the local hardware store (Lowe's, Home Depot, etc.). It is metal electrical conduit and the cheap bike builder's friend. They are almost always galvanized (zinc coated). Please make sure that you sand/wire wheel/chemically remove the coating 2 inches or so away from where you will be welding. Also weld outdoors and use a fan to blow the fumes away from you (blow it across the work in front of you). Burnt zinc fumes will give you metal sickness which isn't deadly, but it's really unpleasant and long-term not too good for you. There is and 'ible somewhere that shows how to remove it with drain cleaner or toilet cleaner (can't remember the details, so you might want to look it up). I always sand the ends with emery paper until you get to the shiny metal underneath. If you can find a copy of "Atomic Zombie's Bike Builder's Bonanza" from your local library, it's definitely worth a read. The author (Brad Graham) is on the site and has posted a couple 'ibles as well. I didn't end up building any of his designs, but they are a good starting point if you haven't done anything like this before.
ininlolo6 years ago
i loved it thats cool
would a 20" bike work,too?
homba (author)  sayoian995 years ago
It should - you'll probably want to bump your tubing up to the next size (or measure the bike frame tubes and match them).
traceuis5 years ago
I guess I missed the step where you explain the steering mechanism. Could you give me some detailed information on it? I have a couple of donor bikes and I'm currently learning welding, MIG, TIG and 70/13 as well as fabrication. Thanks
homba (author)  traceuis5 years ago
It's pretty basic - add another steering tube and handlebars in reach of the driver. Attach tie rod ends to tabs the same distance apart from the pivot point of each steering tube. cut and thread a piece of round metal stock to connect the tie rods. If you have any more specific questions, feel free to ask. You may also want to check out my other recumbent instructable. It uses the same steering set up.
SirJoey5 years ago
Homba, I really like the looks of this bent. I'm considering building this one with 24 or 26 inch wheels, as an adult's bike. Any thoughts? Thanx! :)
homba (author)  SirJoey5 years ago
Yes - do it! ... and post photos! ;)

Check out my other 'bent instructable for an adult version. Recumbents are great if you want to go fast and want comfort. If you can scrounge free bikes and have access to a welder, you can make a fantastic bike for super-cheap!
SirJoey homba5 years ago
(removed by author or community request)
homba (author)  SirJoey5 years ago
You're all set, then! I would say this is an easier build than my other one, though. Also, you don't have to fool with chain management either. I wasn't terribly happy with the steering on this one. I ended up putting in a stop as the wheel could flip around backwards. It wouldn't do it while riding, but it freaked my kid out.
Rockerx5 years ago
Well I have the parts...finally. but I decided I'm going to build something a bit different. I was planning a bike but after seeing what I had on hand i settled with a trike design. so anyway heres my sort of concept video of my project.
Just thought you'd like to see it. i'll let you know when I get it done!
good concept!! thats exactly my idea also but settled on a 4 wheeler that is almost complete. see pic.
' how do i upload a picture?
Thanks! For the pic just hit add images and click upload from my computer...or something like that. I'd like to see it.
homba (author)  Rockerx5 years ago
Front or rear wheel drive? Front would be easier to build - check out http://www.python-lowracer.de/ for ideas. There are several people that have made trikes in this style and they work well. Here's my version:

looks pretty nice i've always been turned away from that design how well does it steer?
homba (author)  corey_caffeine5 years ago
The center steer stuff is really squirrely - it took me several hours to learn to ride. There are severl trike versions that are pretty nice - you can keep your hands free while you bike!
i think i might do a rear wheel steering tadpole trike so i dont have to do the crazy pulley stuff
is that yours?
Rockerx homba5 years ago
Front, I was thinking I could take one bike and cut off the handlebars and front wheel. Then flipping that upside down so that I could use the bottom bar (old top bar) to weld on the pipe to extend to the back steering and seat. I like yours in the video. It has a pivot in the front for turning right?
Excellent instructable, great explanations, great photos, great final outcome... Really impressed by the whole project... As another easy way to create the remote steering you could take two same sized sprocket add them to the respective steering tubes then attach a chain... It would be one more part that needs oiled but it would be relatively simple...
homba (author)  killerjackalope6 years ago
You'd have to get the alignment right, but I like that idea. It would look pretty cool too if you did it right.
The trick to alignment would be simple, lock the wheel and bars dead straight and then put the chain on, pretension it and basically make a locked out design, so you have to split the chain again to remove it. You could even gear it up or down slightly for looser or tighter steering, I'd imagine at higher speeds a slightly loose design would be good but a higher geared setup would be best around town...
I thought of something similar for the project I'm currently designing at http://electricle.blogspot.com, except that instead of two sprockets and a full chain, it uses a short chain (just enough to complete the necessary steering semicircle), and two lengths of cable.

The sprocket is on the bottom end of the steering tube, just above the fork itself, rather than at the top (tougher to setup but I need it as low as I can get it). The sprocket will be setup so that I don't have 1:1 steering ratio, but rather so it is more like "power steering", in that a minimal movement of the handlebars will result in a normal movement of the steering at the wheel itself, because my arms have a lot of trouble with steering normally (I'm getting older and joints aren't what they used to be--the less I have to move them under load, the better off I feel!).

The cables each have one end fixed to a different end of the chain, and the other end of each cable goes thru a pulley mounted on the down tube to one side of the under-seat handlebar. One side is a standard cable clamp, and the other side is a tension adjuster from an old brake handle, so I can fix it as the cable stretches. :-)

I thought it was a nice original idea, but I've remembered that I've seen most of the idea somewhere else (dunno where, though). Not sure if they had any kind of fine tension adjustment, though.
Well for the adjustment a barrel adjust can be spliced in to a line nearly anywhere the housing ends and starts depending on the adjustments needed, granted at the shifters is simplest or down on the dérailleur... As for the steering if you find it easier to move your arms less distance then gearing up a little to have sensitive steering would be good, it would be a little disconcerting to learn but would guarantee that no thieves would get too far before making a mistake... The idea I had is pretty much the same as that, just a closed loop and I considered that a simple tensioner that locks in place could be used to lock the chain on but make it removable for service and adjustment...
Didnt' think of the barrel adjust, but I don't have one in my junkpile, and nothing will be bought for this bike. :-) Unless you're referring to the type of adjust that can be done at the ends of most cabled controls these days, with the twist-barrel grips at the insert points of brakehandles and rear derailers and such, in which case that's already part of the plan, on one end of the handlebar mountings for the cable. I did consider a chain loop but I do not want to be restricted to an essentially parallel axis for both handlebars and steering, so I decided on the cable between the sections--as soon as I did that, the entire handlebar sprocket/chain end went away as it'd be more effective to mount cables directly to the bars instead, for my purpose. Plus I couldn't figure out a good tensioner that didn't add too much complexity for the chain, that I could build easily from junk bike parts. :) I hadn't considered the possible effect on thieves, but I'll take anything I can get over them. :-) Since even the Dayglo Avenger I ride now is covered in recycled bits for various purposes, and is pretty ugly and uniquely visible, it's been at least a bit of a deterrent so far. Also it's really really heavy, which helps. (weight to be fixed with the new one, though, I hope). (this is a pic of the DA one motorization version back, the motors are now between the seatpost and the rear wheel, and the batteries are in front of the seatpost):
BikeMotorizedLeftside.JPG
1-40 of 68Next »