STI (integrated shifting) was less than ideal for tandems when it was first offered by builders back in the 90's. Shimano's STI in particular was awful when it came to front derailleur shifting. In fact, STI was late to the party on tandems because it was not offered in a triple front derailleur configuration until several years after STI first arrived. There are a lot of folks out there who still cling to the early problems that recommend bar-ends, rightly or wrongly.
Originally Posted by ChristineS
Anyway, as I said, the front derailleur shifting was awful because there was no trimming (the ability to make small adjustments to the front derailleur position), just the fixed stops for the big / middle / small chainrings based on single bike / 130mm rear spacing. For tandems with their 140mm, 145mm and in particular Santana's 160mm rear spacing it created all kinds of problems with mis-shifts, overshifting and the like which truly needed something like the non-indexed trimming afforded by the bar-end shifters that had become standard fare on stock non-racing tandems. Racing tandems used downtube shifters which, again, afforded riders non-indexed front derailleur shifting.
Enter Campagnolo's Ergo shifting marketed by Sachs with it's 8-stop (vs 3 stop STI) front derailleur shifting, and problem solved. Sachs was even compatible with Shimano. However, because Shimano had gained such a huge market share as the OEM component offering by the big S (Santana) and others, most tandem buyers didn't get to enjoy relatively problem-free shifting for several years. It took a reworking of STI to add intermediate trim positions in later models of their triple front derailleur shifters to solve the basic problem in later years to 'fix' the STI issue for builders and buyers who were locked into Shimano components (rightly or wrongly), while folks who stuck with bar-ends or who adopted Sachs / Campagnolo Ergo systems enjoyed trouble-free front derailleur shifting, noting that there is no distinction between a "double" and "triple" integrated shifter in the Campy group: all shifters are triple compatible because of the multiple index positions.
Anyway, in the mean time, old-school tandem enthusiasts cooked up all kinds of 'reasons' to justify their preference for sticking with bar-end shifters, some with merit and others with less than solid reasoning. They included:
1. Loss of a visual cues for gear positioning, noting that like down tube shifters... bar-ends would give a captain a fairly accurate idea of which chain ring or rear cog the chain was in based on the position of the shift lever. The solution to this valid issue was to, (a) ask your stoker for input, (b) crane your neck and look down and back to see where your chain was, (c) buy or make your own mechanical gear position indicator, or (d) buy Shimano's FlightDeck cyclocomputer with it's electronic gear position graphics.
2. Loss of reliability given the added complexity and cable-wear that came with STI. The latter was somewhat valid in that, Shimano did have some early problems with STI reliability. Moreover, if tandem owners did not replace derailleur cables and housing on a regular basis (like every other year or so), a cable could fray inside the STI lever and create a real mess of a problem.
3. Cost of STi was also an issue because a pair of STI levers was more expensive than a pair of bar-ends + a pair of Dia-Compe 287 brake levers... standard fare for tandems.
4. Finally, there was an issue with brake compatibility. STI levers were developed for road-racing bikes that used compact caliper brakes, not the linear-pull (aka, V-brakes) that had just become popular on tandems about the same time that STI was offered. V-brakes required a different brake lever / cable-pull ratio which necessitated the use of a brake cable pull adapter called a "travel agent". No such device was needed for folks who were using bar-end shifters and Dia-Compe 287 brake levers.
Now, on the other side of the coin were various arguments for STI....
1. For anyone who was riding a relatively contemporary road bike, STI was the state of the art for shifting and it made a lot of sense to have the same type of shifters on your road bike and road tandem: one less thing to think about.
2. For fast recreational, sport or competitive tandem teams, STI allowed the captain to shift while standing on climbs or otherwise while out of the saddle... again, something they likely did on their personal road bikes.
3. For folks buying racing or sport tandems fitted with compact caliper brakes, there was no brake lever / cable-pull compatibility problem.
4. As STI (and Campy Ergo) systems evolved, integrated cycling computers were offered that provided a wealth of features that integrated normal computer functions with gear position indication to create things like 'virtual cadence' that many tandem enthusiasts quickly embraced as an important feature.
Anyway, you get the idea... there were and still are all kinds of arguments to made for and against integrated shifting. They key to me is familiarity. It's weird enough going from a road bike shifting like Ergo to an off-road bike with thumb shifters or grip shifting, why make life even more of a challenge by having more than one type of shifting function on your road bikes. For me, I was an early adopter of the Campagnolo-based Sachs Ergo system and liked it so much that all of our road bikes and tandems (6 at last count) are fitted with Campy Ergo shifting.
Bottom Line: No one else can tell a tandem captain what they "should" prefer; each captain will need to figure out based on their own biases and how they'll be riding their tandem. Short of unsupported world touring, I'd be hard-pressed to come up with a compelling reason for someone who presently uses STI, Ergo or SRAM integrated shifting to not use that same system on their road tandem.
Have a great time tomorrow afternoon.