The difference between a junkie bike and a racing bike?

Question

So I found this used old bike in the junk. My experience with bikes was zero, so in order to fix it I had to learn about bikes on youtube and other places. What I understood is that one can basically build a bike from scratch. I saw some websites were you can buy every single piece of a bike and then assemble them all to make a customized one.

When I looked on the frames on some of the new racing or fancy bikes and then compared to my junkie bike I found the frames almost identical in terms of shape. Of course there was a huge difference in terms of the fancy equipments but to me the most important pattern was that the frame was identical.

I asked couple questions here regarding fixing the bike or painting it, and one time I got a response: "are you really going to spend too much money on that junkie bike?". Then I asked myself the question as to what is the difference between a junkie bike and a new fancy one?

I mean if I spend money on new parts AND considering that the frame is identical to fancy bikes, wouldn't that simply make it as valuable as a new fancy bike? Suppose that every year I change a part and at the end I paint it very well, would that still make it a junkie bike?

I am interested in the answer to know if it is really worth it to spend money on it or not. Because if it is worth it, then maybe I can sell it and make money.

Here are pictures for the bike:

Painting a bike with minimum cost

Safety check for a used bike

Answer 1

From the pictures you've posted across a few different questions, I can almost guarantee you will not make money selling that bike, no matter what you do to it. At the very least you will need a new freewheel and chain, new tyres, cables, and brake pads. Sadly, those will probably set you back more than you could sell the bike for. Given your apparent lack of mechanical know-how, you really should leave the repairs to a professional mechanic, which will further add to the costs.

I believe you underestimate the differences between your "junkie" bike and modern "fancy" bikes. Yes, you can buy the componentry found on "fancy" bikes separately, but most of it will be designed to fit modern frames, which more than likely have different diameter tubing. Although you should be able to find new parts to replace the knackered ones, they are unlikely to be of high quality. Whatever you do to that bike, it will still be heavy and cumbersome. One can't polish a turd, as they say.

Modern, more expensive frames and components are generally lighter, stiffer, smoother, better-fitting, and better-looking... none of which are essential for getting around.

If you don't have much of a budget, the best thing would be to find a local bike co-op and learn how to perform basic maintenance from volunteer mechanics. Otherwise, I'd donate that bike to such a project, and buy something a bit nicer second-hand. Or just get your LBS to do the bare minimum to make it rideable, ride it til it falls apart, then get a new one!