Previous week our street had a collection of bulky waste. In two days I have really seen an enormous number of old bikes. Some bikes were probably more than 30 years old. Typically, old people save their bikes for many decades in their basements and bikes are totally useless now.
Are there are any possibilities for recycling old bikes? For example, bike frames seems a very promising part of a bike to be melted and used for new production? What about tubes and chains?
If a bike is just sitting in a shed or something for a few years (where few can be a few decades), the best way to recycle it is to just throw a set of new tires+tubes+brake pads on, lube up the chain and then go ride it. This is probably the most environmentally friendly thing to do (possibly via donation to a local charity/bike co-op). An ancient bike might require some new bearing grease and stuff, but a bike isn't like the leftovers in your fridge -- you can bring it back to acceptable condition quite easily. You can still ride an old bike fine -- my current road bike is 27 years old (and there are still tonnes of 70's bikes on the road, just not among the road racer crew). If the bike is in very bad condition, usually in a co-op situation or something, you can still strip some parts from the bike and recycle the rest.
As for recycling, there is a huge variation in whats accepted for recycling even between neighboring towns (or even parts of the same town) in the US. You have to check with your local ordinance to see if/how you can recycle them. A scrap metal shop might (unlikely) also take a frame, or artists for art projects. Tires are often recycled on cars/trucks, but I don't know if an automotive shop will take a bicycle tire.
I'd suggest checking with your local bike shop to see how they recycle old bicycles/ chains/ tubes/ tires /cassettes/chainrings/etc. -- there are services which specialize in this, and they may be subscribed to them (and you might be able to use them for a nominal fee or free, maybe). Most cyclists I know use a few of them as ties on a luggage rack or things like that, but you accumulate so many of them that they have to be thrown away.
Check the packaging for the bicycle parts you buy -- if they're recyclable, they should have some recycling logo. Then act accordingly to it for your local ordinances.
I have been working with an outfit called Cycle It Forward for several years now. The group (about 10 active members) collects used bikes and "rehabs" them for use by the "indigent" members of our community.
The bikes are sorted, and those that are in reasonable condition are rehabbed -- cleaned up, tire patched, wheels trued, chains lubed, reflectors replaced. (At least one of the front/rear reflectors is missing about 50% of the time.) The kids' bikes are given away at Christmas by Christmas Anonymous, while the adult bikes are given to adults who need them throughout the year, by way of the county social services workers.
An occasional expensive bike in good condition is sold to provide operating funds, and bikes whose condition is too poor for rehab are stripped of usable parts, have their wheels removed, and sent to a recycler as steel scrap (the wheels being sold separately at a much lower value). We probably could make a little more by separating out the aluminum scrap and selling that separately, but it would be a lot of work and bother.
This year we rehabbed about 350 bikes, in a community of around 150,000, and probably recycled about the same number. We could easily get double the donations, if we had the storage and processing capacity.
Old steel bikes are not worth recycling, in terms of economics. The price on Steel varies, but its ranges from $10 to $155/tonne based on what sort it is. And while an old bike could have up to 20 kg of steel, its fiddly to strip off all the non-steel, and the income doesn't pay for the time.
That's 1c to 15c per kilogram, or 20c-$3 for a bike with 20 kilos of steel
By comparison, aluminium / aluminum is $1.33/kg for extrusion, and $1.18/kg for cast.
Carbon fibre cannot be recycled like metals, so is outside the scope of this answer.
Do note that you have to strip a bike down to less than component parts. And most recyclers will not pay anything for oily parts, so you need to clean all the oil off too.
From a cost perspective, recycling parts that are reusable is poor economics. Recycling only makes sense if the part is unserviceable through damage or wear, as a better answer than throwing them in the rubbish.
tl;dr reuse!
