Introduction: Build a Kid's Long-wheelbase Low Racer Recumbent Bicycle

Picture of Build a Kid's Long-wheelbase Low Racer Recumbent Bicycle
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.

Step 1: Materials and Tools

Picture of Materials and Tools
  • 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

  • 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.

Step 3: Extend Top Tube and Chain Stay

Picture of Extend Top Tube and Chain Stay

Measurements are tough on this one, but you will need to add conduit to stretch the bike out. Base the measurement on the length of the rider sitting down with legs stretched out. The new tubes should allow for the measured length from the seat back (with padding, etc.) to the pedals when they are as far as they get from the rider.

I was able to jam the new top tube piece into the old top tube and weld. If I had more time, I would have smoothed this transition a little more with body filler. Weld the top tube about halfway down the seat tube.

The new chain stay piece will attach centered up where the old one did on the bottom bracket. you will have to make a little bracket for it to attach to both the bottom of the seat tube and the chain stays. If you attach the new tube to the bottom of the seat tube, it will be too high to weld to the old chain stays, so I cut the tube so that I can weld a piece of 1/8" stock to both the new and old chain stays. That bracket is shown below.

I do my best to keep everything straight and have had pretty good luck with eyeballing it. These long bike frames are long enough that you can see if something is off. If you aren't confident in your eyeballing abilities, clamp the frame to something you know to be straight when you weld to form a temporary jig.

Step 4: Steering

Picture of Steering

Now to create the remote steering. This is where a second head tube assembly from a junker bike is handy. If you are clever, you could fabricate something and just use one bike for the project.

The measurements are iffy on this one. You will want to measure it to the passenger. The easiest way is to assemble the head tube together with handlebars and have your rider hold it somewhere comfortable. Measure up for a riser tube to mount the head tube to, cut, fit, and weld. Try to make sure that the remote head tube is close to the same angle as the donor bike's head tube. Its also good to make sure that you can make the tie rods for steering fairly level.

My tie rod ends were from Wick's Aircraft Supply and are really nice, but probably the most expensive part of the bike. I've heard of people buying them cheaper at Summit Racing Systems (which is only a few miles from me - d'oh!). The images below illustrate how the tie rod ends are connected. The tie rod itself is made from 1/4' scavanged round stock. I cut threads to match the tie rod ends.

To make sure things were secure, I created a gusset for the remote steering tube out of and old crappy kid's bike gear.

Step 5: Seat

Picture of Seat

The seat is simply plywood with a few brackets holding it together. I covered it with foam and some leftover denim fabric I had. The seat is attached at the bottom with brackets made from tubing split down the middle with wings attached. See the photos for details. The rear bracket is bolted to the old seat adjustment bolt holes. In theory, you can re-drill the bracket and scooch the seat back as the rider grows.

Step 6: Prep and Paint

Picture of Prep and Paint

Go over all your welds again and fill with body filler. Sand the body filler smooth, prime, sand, and prime again.

The paint my son chose was fluorescent yellow and was a flat finish. To make it shiny, I added a clear coat.

The front fork was painted gloss white with a coat of 3M retro-reflective clear. You can really see this bike coming. It's hard to look at in the sunlight!

Painting all the little brackets was time consuming, but worth the effort. I even ended up painting the old Raleigh emblem white and refitting it.

Step 7: Assemble and Ride!

Picture of Assemble and Ride!

I let the paint dry several days in the sun. It still is soft (a year later!), so I have to be careful with it on the bike rack - I usually wrap and contact points in a plastic bag. I ended up cutting out small grommets and washers out of a 2-liter soda bottle so that the nuts and bolts wouldn't mar up the finish.

I gave everything a good dose of quality bike grease and cleaned up and lubricated the chain. After mounting and adjusting the brakes and the shifting mechanism, we were ready for a test drive. It was a little twitchy at first, but he got the hang of it quick.

I added a few photos with measurements so you can get an idea of seat size, etc.

This bike turns heads everywhere we go with it. My son likes the ride and loves the attention he gets. Because it's a 3 speed and comfortable, I can take him with me on rides that I couldn't before.


AronC0816 (author)2013-08-01

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!

davec8656 (author)2011-05-26

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.

MACKattacksnipe (author)2010-08-04

for the steering i would have just cut the frame and re welded it so alls you need is a longer peace of pipe

rlnbkseeberger (author)2010-07-27

This has inspired me to at least try to build a recumbent unicycle. Now that would look cool cruising down the street.

japanbiker (author)2010-03-27


idiosyncrazy (author)2010-01-01

 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.

sayoian99 (author)2009-06-23

can you mass produce those?PWWEEEESE?

homba (author)sayoian992009-06-23

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 (author)homba2009-06-24

is it possible w/o welds,and on a budget?

homba (author)sayoian992009-06-24

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 (author)homba2009-06-24

well,the idea for my bike that im making is more like the one shown

homba (author)sayoian992009-06-24

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 (author)homba2009-06-24

do you know where i can get a 20" bike for about $10-$20?(for front wheel drive.)

homba (author)sayoian992009-06-25

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 (author)homba2009-06-24

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)sayoian992009-06-25

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.

ininlolo (author)2008-07-27

i loved it thats cool

sayoian99 (author)ininlolo2009-06-24

would a 20" bike work,too?

homba (author)sayoian992009-06-25

It should - you'll probably want to bump your tubing up to the next size (or measure the bike frame tubes and match them).

traceuis (author)2009-04-23

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)traceuis2009-06-23

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.

homba (author)2009-02-24

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.

SirJoey (author)2009-02-23

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)SirJoey2009-02-24

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!

Rockerx (author)2008-08-29
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!
blackflashdog (author)Rockerx2008-12-18

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?

Rockerx (author)blackflashdog2008-12-19

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)Rockerx2008-09-02
Front or rear wheel drive? Front would be easier to build - check out for ideas. There are several people that have made trikes in this style and they work well. Here's my version:

corey_caffeine (author)homba2008-10-01

looks pretty nice i've always been turned away from that design how well does it steer?

homba (author)corey_caffeine2008-10-01

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!

corey_caffeine (author)homba2008-10-05

i think i might do a rear wheel steering tadpole trike so i dont have to do the crazy pulley stuff

corey_caffeine (author)homba2008-10-01

is that yours?

Rockerx (author)homba2008-09-02

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?

killerjackalope (author)2008-07-23

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)killerjackalope2008-07-23

You'd have to get the alignment right, but I like that idea. It would look pretty cool too if you did it right.

killerjackalope (author)homba2008-07-23

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, 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):

Aye that's the type I meant but you could probably figure a way of using on at the other end if needed or anywhere since there only need to be a solid point that stops the cable cover moving and a a mount for the adjuster, granted the handlebar is the most logical place for such a thing. Tensioning the chain would be as simple as two old dérailleur hangers with the guide sprockets in place pulling the chain taught in the middle, alternatively you could throw a spring dérailleur on one and and it would hold aswell but be pretty messy and not that attractive... The cable steering would be simple enough though may not be that reliable as it would be hard on the cables and change often as they stretch. A possible steering option that doesn't limit you much on any axis would be using two gears and a trnasmission shaft of sorts, when the bars turn the gears turn at a 1:1 ratio down to the forks, you could have it pretty much any way as long as the gears mesh, one cool trick would be to make the shaft mounted gears much smaller than the gears on the forks and bars, still identical at each end but the shaft would spin insanely fast, apart from looking cool it wouldn't be much use though... Many thieves are deterred by bikes that are customised or out of the ordinary in a big way, they're more recognizable, potentially difficult to ride and harder to move on if they're a selling thieve...

I actually have a shaft design for both steering and drive to be used on the airshocked trike 'bent I'll be building once I can find all the parts I need (airshocks are hard to find used even in junkyards, as are small enough u-joints). But for the 'bent I'm making now, it's too complex and I don't have the u-joints. I figure if the cables dont' stretch much on my shifters (which are under constant tension in one gear or another), they ought not stretch too much on steering either, though I know it's more of a load. I think any method I were to use to tension a direct full loop of chain would end up seriously in the way on the current design (even the chain would be, too); the cables have the advantage of being routable in ways a taut chain is not. :-) I definitely appreciate the feedback on my comments/ideas, as they give me food for thought for future versions!

Airshocks you say? You could actually look for pneumatic pistons, block out ports and add a no return valve with a pump adapter on the end, not you can change the pressures on the fly. Though hydraulic pistons would work just as well they're usually much heavier in build, not mention messier to work with as the oil tends to hide in them. Well I did just think of something, using a slightly heavier weight cable would likely solve the issue, you can get braided steel cable a couple of mm thicker and it's very strong, granted if you're making the fly by wire system from scratch you can use any sizes you want. I think the chain idea would be cool on something more audacious, I'm thinking paraffin lubricated since it's not under and serious duty... Anyway, good luck with your projects, I hope to see them up at some point. Oh by the way, if you're having real trouble finding U -Joints, I assume you mean ones for the frame, you might be able to find rated pipe that's strong enough to do the job. Oh and when you do route the cables don't spend hours removing the little clips, a bandsaw and some small diameter pipe can be turned in to them...

Well, the thing with airshocks is that they don't have to operate in a perfectly straight line like pistons probably would, and don't have any really precision-fitting moving parts inside. I dont' need to change pressures on the fly, but I will need to be able to air them up or down (with a bike foot pump I carry for tire issues anyway) when I'm out and about picking up or dropping off cargo of various kinds (mostly groceries, but also various Freecycled items), which will be carried in cargo pods or baskets on the trike, mounted to the shocked section of the bike to aid in carrying more fragile loads than I possibly could now. Since the bike will have different weight on the shocks with different cargo (or none) it will have a different ride if I can't change the pressure. :-)

Hydraulic pistons are right out for their weight, the oil, etc. :-(

I can't get thicker cable for *this* project because it's made only from the parts I have now (as a challenge, mostly). But it's a thought for the future. I have a small roll of guy-wire for a ham-radio tower that'd surely work, but it's so thick I think it would not bend easily enough at the pulleys.

The full-chain idea could be useful but definitely not on this one. I'd like to see what you finally do make with it!

I haven't looked for U-joints much yet, besides in a couple of non-working cars in the driveway, and a spare new car-driveshaft U-joint in a box of parts, but those are all too big and heavy to use on a bike--each one weighs at least a couple of pounds, and I'd like to not add that much weight in any one spot. I was figuring on making the ones for the airshock bike from scratch, if I had to (a while back, I saved an article somewhere on how to do that, if I can find it again).

Which little clips do you mean, on the cables? And I don't have a bandsaw, just hand tools and a Dremel, plus a 4" anglegrinder, 10" circular saw, and dinky cheap AC flux-core wire welder. Lucky to have those, as it is. :-) I'm assuming you mean the clips for the cables to route in on the bike frame--if so, well, I don't have any pipe near that size, so wherever I need those clips I have to transplant them from the scrapped bike frames. I'm trying to strategically use the existing ones wherever they end up when possible, but there are a few I know I'll have to cut off with a hacksaw and reweld (a couple of them on extended tabs away from the frame proper).

That piston thing was meant say you can change pressures on the fly...

"one more part that needs oiled" On reading that my thought process was as follows: "needs oiled"? Ah! Northern Irish grammar. killerjackalope? *reads comment poster's username* Ah yes, so it is. I miss my brother, why must he be in Africa? OK, enough crazy thoughts. (the last one probably wasn't relevant to the post) Keep it up homba, great Instructable.

Confusion spreads to others who read the post...

bedbugg2 (author)2008-08-07

thats sick!

dpocius (author)2008-07-24

Very cool! Reminds me of a bike project I saw in a Popular-something when I was a kid, back in the '60s. Same basic idea, except it used a near-horizontal steering shaft with a universal joint at the top of the fork and a homemade airplane-style steering yoke. I think I still have a copy (before Xerox!) of the scaled plans somewhere. Now I'm inspired to dig it out and build one after 40-odd years!

homba (author)dpocius2008-07-24

It's not this, is it? I remember what you are talking about, but I haven't seen it in a while. My dad used to pick up lots of back issues when I was a kid ... I'd really like to know why my mail isn't delivered by rocket, though. It seemed like such a good idea at the time ...

bob.smitty (author)homba2008-08-07

Not as good as the 20 hour week, the helicopter replacing the car and the self cleaning house... the future isn't what it used to be. *sigh*

About This Instructable




More by homba:Build a kid's long-wheelbase low racer recumbent bicycleBuild a long-wheelbase low racer recumbent bicycle
Add instructable to: