What is the biggest component difference between a cheap road bike and an expensive road bike? I am shopping around for road bikes now, and I wanted to know what components to look for. I am not talking about the frame, carbon or otherwise, I mean types of shifters, brakes, cranks, rims, etc.
As with any other equipment, it depends on how much you would like to spend...

The main difference between a cheap and a better bike is the quality of the materials and the comfort/performance they provide!

I have several cheap bikes and two "better" bikes, the differences between these are:


better derailleur system, both the front and back, it makes a lot of difference!
better shifter (the cheap one has a thumb-type shifter, and the better has a shimano trigger-type shifter), for me having trigger-type shifter is a huge difference in comfort
better brakes (you could go for the v-brakes, but there are some flavors to choose from; you could also go for a disc-brake; also the brake levers can make a lot of difference also!)
tyres, normally the cheap bikes have sub-par tyres and tubes.
obviously the wheel (good rims, good spokes, I have noticed that indeed!)
the frame, weight, strength, shape (cheap frames can affect a lot on the way you ride, but honestly I've had cheap frames and loved them!)
seat, a good seat and seat post are important.
overall, good materials, that don't disintegrate after some time and resist (as possible) to the corrosion.


I may have forgotten something but this gives you an idea.