Troul 

Thinking back to the days of old clunker bicycles I've had & comparing those to what I would value more "higher end" it seems as tho the clunkers with derailleurs shifted well & the most noticeable thing was during shifting it was less delicate sounding (more of a clunk) . The other bicycles that were more expensive & often contained sought after group sets required more attention for adjustment not just for initial setting up, but also throughout use. They were less noticeable during a shift, however, both the "cheaper" & "higher end" derailleurs I've experienced shifted just as fast, barring any installation errors or other defective parts dictating shift speed.

With the above, can you relate to that or are my experiences all anomalies?

rayooo

yea it seems to me that the basic techniques for getting a bicycle chain moved over to a different ring or cog has been pretty well understood for many years. Some basic tweaks have surely occurred with respect to the ramps and bumps etc. on the rings and cogs but the actual speed/quality of the shift has been good for ages.

Overall, though the refinement of the user interface has changed dramatically, the actual shifting speed and process is and has been about as good as it'd going to get I'd think.

More recently I spent months getting an Ultegra drive-train set up to where it now works fantastically well! And even more recently I've been riding a eTap Red equipped bike. Once again the user interface has changed (which I like very much) and I've done far less fine-tweaking than with previous cable based shifting systems. As far as the actual shifting performance, it's essentially identical to Ultegra... and my old rusty Shogun shifted good also considering the UI was click-less.

Troul 

I will say that since going to brifters away from triggers, I like that I can "trim" the RD somewhat. The FD is not as trim friendly, but it is also less likely for me needing to trim up front.

Wilfred Laurier

Older bikes generally had fewer cogs with wider spacing between them, and this made the systems more tolerant of slight maladjustment. On 6sp and less, the positive 'clunk' when the chain moves tot he next cog is almost as good an indicator of a completed shift as the clicks in the shifter on a modern indexed system.

When new, the less expensive derailleurs and shifters (from Shimano , anyways, not so sure about Sram) work damn-near as well as the more expensive ones. The difference is that the cheaper ones wear out and get sloppy and hard to keep adjusted much faster - a brand new Tourney derailleur is astonishingly good considering the price, but after a season of use you can definitely tell it isn't top quality stuff.

86az135i

Remember difference in cogs between one gear to the next makes a big difference. So higher end systems usually are found on higher end bikes that have a high number of gears and generally 1 or two cogs between shifts.

MNebiker

Back in the 80s we had a his/hers pair of Schwinn 10sp World Tourist bikes. These had the friction shifters with Shimano derailleurs - SE front and Lark rear. These things seemed bulletproof and actually shifted fairly well. I did an annual strip down, lube, & tune on the bikes and we rode them for years, finally selling them in 2002. They both had the Shimano FF (Front Freewheel) system that had the freewheel in the crank rather than the rear hub. I always liked that because the chain was always in motion when the bike moved and you could downshift while coasting. Worked pretty slick and there didn't seem to be excessive chain wear. There are those occasions where you get caught in a high gear that make me wish it was still available.

With the great trails in this area I upgraded to a lightweight commuter 24 spd, but about 10 years ago I ran across a mint set of those same bikes that I picked up cheap and resold after refurbishing them. Both had the FF system, but the women's bike had the Shimano Positron shifter and rear derailleur instead of the old Lark. This was one of the first detented shifting systems, and unlike the modern systems, the detent was built into the derailleur rather than the shifter. Instead of a cable it used a solid steel wire similar to the old manual choke on cars. I had always heard these were a beast to adjust and make work smoothly, but I was apparently highly skilled (lucky) as it seemed simple to set up and actually shifted quite well.

Shimano later came out with the Positron II that replaced the solid wire system with 2 cables but I don't think that Schwinn ever used it on any bikes.

That old stuff worked OK in its day, but seems clunky and archaic now. My wife loved to ride but never really liked the friction shifters She would have enjoyed the modern stuff much more.

Retro Grouch 

How thin can you slice the baloney?

Shimano sells components in so many different group levels that I can't keep track of them anymore. The truth is that even the cheapest Tourney line components work pretty well and the higher prices groups work even better but I have to jump up 2 or 3 price levels to feel a performance difference. As you move up the food change the functional improvement line is pretty linear but the price line moves up exponentially.

You mentioned performance improvement over time. I'm wondering how much of the improvement that we enjoy today is due to improved cable housing rather than the components themselves.

Troul 

Not necessarily a performance improvement, just less noise during a shift. The speed of the shifting wasn't any better between the two from my experiences.

Ironfish653

I think a lot of it also has to do with the attention paid to chain side profiles and the design of shifting ramps on chainrings / cogs.

I have a '70s Bridgestone as my 'townie' / path-bike. It's still running most of it's original Suntour/SR drivetrain. It's a DT bike, so there's only a couple of inches of cable housing to deal with, (still spiral-wound btw)
There's definitely a mechanical feedback in the shift levers, you can 'feel' the moving parts of the V-GT doing it's thing. Originally a 5-sp, now a 6-sp, so a single shift takes an appreciable amount of cable travel, compared to my 9-sp 105 bike and even the 7-sp XT (1990's)

The big difference in shift quality on that bike occured when swapped the early '80s 5-sp fw, and the flat-sided Sedisport chain for a Shimano TZ-21 fw and a KMC Z-51 chain.
There's no more 'clatter' during a shift, once you hear the chain catch, it's up to the next gear, and any thing else is just trimming. There's still lots of pull, and you definitely know things are moving back there, but it's much less fussy than the old stuff.

big chainring 

I'm perfectly happy with Simplex Delrin derailleurs on 5 speed freewheels. I actually prefer them to anything else.