This instructable explains how to save two old bicycles from the grave to create one immortal tandem bicycle.  

I had always fancied building something for fun and actually dedicating a bit of time to a project rather than just the odd quick fix here and there.  With a charity bike ride looming a couple of months away it seemed like a great idea to try to build a tandem and enter it just for fun.  A few friends and I had entered the event the previous year dressed as glam rockers and it got a good response so we decided to repeat it this year.  (Hence why this tandem has a bit of a Gothic look to it!)

I had never ridden a tandem before and didn't really know what I was aiming for so I looked online at some different frame designs to gain some inspiration.  I decided that I didn't want my bike to look like two bikes - I wanted it to look like a genuine tandem frame.  I also learned that having a decent spacing between the driver and passenger was essential to ensure that the passenger could actually see some scenery and not feel too cramped on the back.  Throughout this instructable I refer to the driver as the 'captain' and the passenger as the 'admiral' because this is proper tandem lingo dontcha know!

This bike cost very little to build as most of the existing components were cleaned up and reused.  The only parts bought new were bearings, chains and cables.  The only really specialist tools I used were a bicycle chain tool (cheap) and a MIG welder (err, not so cheap)

Tools you will need:
- A pair of grips
- A pair of pliers and cutters
- Allen keys and spanners (various sizes depending on your donor bikes)
- Hammer/Mallet (for persuading stubborn bike parts to come off)
- Screwdrivers
- Sandpaper
- G-clamps or large magnets (for holding the frames together when welding)
- Angle grinder (with cutting disc and grinding disc if possible)
- Metal hole cutters (you could use a hacksaw and then file the tubing to shape but this takes a LOT of time)
- A pillar drill (a pillar drill is ideal in order to cut the angles more accurately but a similar result can be achieved using a hand drill and a jig)
- Bicycle chain tool
- A MIG welder - or gas/TIG if you have one available!
- Some wood to make up a frame jig prior to welding
- Spray paint (primer and colour)

Other things you will need:
- Some old bikes! (Free)
- Piece of mild steel tube (from scrap metal yard £10 / $17)
- Paint (£25 / $40)
- Bearings and cables (£10 / $17)
- Chains (£7 / $11 each)

Step 1: Donor bikes and Dissembling

First things first - you are going to need some donor parts.  By using some old bikes that were destined for the bin; a) they were free and b) this project incorporates recycling in its purest form  : )  

The donor bikes were sourced for free – I found two in a skip and the other in the garden of someone’s house.  (I did ask before I took them!)  I figured that the third bike would come in handy for some extra spares should I need them.  All three were in a pretty sorry state and rust had got to most of the components.

The fun begins by unbolting everything from the old bikes.  You won’t need much in the way of specialist tools for this although a chain tool is essential for breaking the chain and will come in handy later on when the new chains are to be sized and fitted.  A crank extractor tool will also make it a lot easier when removing the crank arms from the bottom bracket but this is not essential. If you've got a wooden mallet and a good shot then hit the cranks hard and they will come off eventually.  It ain't pretty and I wouldn't advise doing this on anything other than an old bike where the frame is steel and the cranks are massively over-engineered!  Basically don’t go trying this on your carbon cranks!  : )

To remove the bottom brackets I used a pair of water pump grips to get the bearing cups out of the frame.  You need to remember that one side is a normal thread (undo by turning anti-clockwise) and the other is a reverse thread (undo by turning clockwise).  This also applies to the pedals where they bolt into the crank arms but I will go in to more detail on this later.

As you can see the bearings looked like they were due a bit of a service(!!) Due to how badly corroded they were. I scrapped them in favour of some nice shiny new ones.  I also cleaned all of the cups out with sandpaper and a wire brush so that the bearings could glide around happily in some slimy new grease.

If the brake and gear cables look in good condition (shiny metal and not frayed) then you may wish to reuse some of them if you’re doing this project on a budget.  In the interests of safety and smoother braking/gear changes I’d suggest you replace them all as they are very cheap and it means you don’t have to waste time undoing the old ones – snip, snip!

To remove the forks, undo all headset bolts and the steerer tube nut (the nut at the top of the forks where they clamp onto the handlebar stem).  You will then be left with two bearing cups in the head-tube of the frame (top and bottom).  To remove these you can either use the proper tool (boring!) or get a wide bladed screwdriver and tap them out gently with a wooden mallet ensuring that you tap equally all round the bearing cup to prevent it getting stuck at an odd angle. Also be careful not to damage the surface where the bearings sit.

Everything else will unbolt from the frame with spanners and Allen keys.  Eventually you will be left with a tray full of rusty bits, a couple of old frames and some well used wheels!
<p>Nice build. I'm glad to see others are re-cycling those old bikes.</p><p>I built one of these about 25 years ago. My wife and I decided to buy a 10 speed tandem, only problem was the $500.00 price tag. I picked up a couple of 10 speed bikes, with lug frames and cotterless crank sets. These bikes are higher end stuff. </p><p>I split the headstock on the rear frame. And attached it to the forward frame. I eyeballed the alignment. I did have one small problem. I had wanted to put a larger frame in the front, and small to the rear, for my wife. The way the frames were damaged, I had to reverse the sizes. Since my wife can't ride a bike, I'm on the smaller frame. But, for a freebee, who cares. The thing handled well, was very soft on bumps. There was enough spring in the frame to absorb, all kinds of rough pavement. We never had any problem with breaks. I didn't weld the frame. It is all brazed construction. </p><p> We had several people stop us, to inquire about the bike. I finally broke down and put a name on the diagonal. &quot;Re-cycle&quot;. I had a few riders, ask us where they could get one. They were always surprised to learn that I had built it. I'll post a picture. </p><p> We haven't ridden ours in quite a while. It's out in the barn. I'll post a picture. But you have to not laugh. I paid $.29 for the paint. It's powder blue. </p>
I love Metal too.
Nice effort. <br> <br>I am shit frightened of bikes coming apart underneath me, especially at speed, down a big hill, hitting some rough road while going fast, with a truck coming up behind me. <br> <br>Just horrible - and almost entirely avoidable. <br> <br> <br>There are two sorts of frame failures.... the slowly developing ones - that give plenty of warning when things get a bit loose and sloppy... over time, or where they go &quot;wobble wobble&quot; and then the frame breaks in two. <br> <br>I think this would be a very lovely bike for the casual riding - like 20Kmh around town and country side rides. <br> <br>I'd be a little bit wary of going down big hills fast, on pot holed roads, with trucks up my arse. <br> <br>For a serious bike - I'd be getting a proper engineering books on welding, the engineering of tandem bicycle frames and the properties and treatments of assorted frame building steels. <br> <br>It's like the subtlties of bolts. The classic 8mm bolt - then the classic high tensile grade 8 - 8mm bolt... and then the aircraft certified high tensile bolt. <br> <br>They do not use corner bolt / auto shop high tensile bolts in air craft..... <br> <br>For good reason. <br> <br> <br> <br>I'd also be doing a basic welding certificate - at least to be able to use all the equipment with reasonable competency. <br> <br>Nice job on the butting up of the frame tubes. <br> <br>
If the grips don't slide on easily, lube with hairspray instead of soap or plain water. It dries quickly enough and won't slip once dry
iron maaaaaaaaaaiden
Nice project for a good cause! Well done.
Nice job on the building the Iron Tandem! I have a classic tandem and I always thought it would be great if the stoker would be setup to do the shifting. Only so they would be considered more a part of the team and give them a little responsibility. <br> <br>Great job posting and I wish you the best!
Where did you buy the bicycle parts? Could you suggest me a cheap bicycle-parts website?<br>Thanks and nice work!!
Ebay is good, craigslist is better! If don't really know your bicycling &quot;stuff&quot;, I would look for a local bicycle co-op. Hopefully there is one. If not, there maybe people from the local school that would be interested in starting one. <br> <br>Oh, also your local freecycle.org is a good source for free bikes and parts.
Hi and thanks for your comment. I use Chain Reaction Cycles online. eBay is also good for used parts and parts for older bikes. Good luck!
Good job, and lovely pix, though some presented at odd angles. I enjoyed your instructable. Lots of good tips.
or the grips you should use dilute soap solution, dishwashing soap works just fine. Once it dries they're stuck on. I've used this method for years and years. <br> <br>Also you can keep all the chains on one side if you tie the two cranks together with a fixed chain around the two smaller front chain rings. <br> <br>See Brad's DIY tandem here at Atomic Zombie: http://www.atomiczombie.com/Tutorial%20-%20Simple%20MTB%20Tandem%20-%20Page%201.aspx
I don't know if it would work but you could always try warming the handlebar grips with a hot air gun (or hair drier). It may just expand them enough for them to slip on easier. Another thing. Have you considered brazing the tubes together? Much less chance of distortion and a braze is certainly plenty strong enough. I had a fair few bikes with frames that were brazed in my teens.
at first glance I thought this was titled &quot;Iran Tandem&quot; :-) while you haven't had any problems, I'd question some of your very important welds, the penetration doesn't seem very good. when the welding bead looks like caulking there is little strength and it is just laying on top. nice job on this article.
Saw the logo on your bike pic and immediately started doing the intro to &quot; The Trooper &quot;..... good job and up the irons
Nice! MIG is fine for thicker walled tubing- I've done it plenty of times and it works best on the less expensive bikes that use high tensile steel tubes. It's the more expensive bikes that use the thin walled chromoly with short butted sections on the tube ends and for those TIG is the way to go.

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