Originally Posted by esldude

Okay, I will give a partial answer. I have a 1980 bike, 12 speed, that I rode sporadically for a long time. Couple years back got an up to date road bike with 9 speed cassette. Wondered how much difference it made. Both bikes fit me well. Old bike weighs about 5 pounds more.

Over a completely level, paved loop, I rode twelve miles twice on the old bike. Averaged 1.0 and 1.1 mph less than on the newer bike. My speed was slower mainly due to gearing. The old bike I had one gear that had me spinning a bit too much to be comfortable or slowing down. Or switching up to the next nearest gear was just a bit too tall for me to continue pulling for long.

So bottom line, little other than convenience has improved in general on road bikes. Other than more gears. Brifters are convenient, the old bike had friction shifters. Weight is a bit better, not much of a deal on a level course. Stiffness is a bit better, but the old bike was stiff enough. Brakes are better, but not a huge concern. So more gears makes you faster by being able to keep your cadence and load closer to the optimum range.

Now about quality of parts, well sure that plays into it. Just basic things like feel, durability, reliability. Get too cheap, and bearings and such won't last or have more drag. Lighter wheels are always good to have.

So I don't know, get an older top quality bike and put more gears on it. Get a newer bike of decent quality and ride it. If you are hoping a cheap bike with more gears will get you similar results to a good bike with more gears, well sorry, no it won't.