Originally posted by Davet
The 'problems' I'm having with STI shifting, is primarily shifting down under pedal pressure, like going up a hill. On my solo bike no problems, I can relieve the pressure and the shifts are fine. On the tandem, it's difficult to relieve the pressure on the pedals to allow the STI's to shift, without throwing the cadence or rhythm off.
You didn't mention if it was the front or rear derailleur that was resisting the shift so I'll go out on a limb and assume that it may be the front as this is the one shifting scenario that perplexes most new tandem teams; but, the same "cause-effect" can also make rear derailluer down shifts "ugly" as well as big ring up shifts.
This is most likely -- and again I'm guessing -- a team-work issue where your Stoker still has the drive train loaded up while you are trying to shift. When most people ride a single bike and shift -- knowingly or not -- they reduce pedal pressure ever so slightly. It's almost an intuitive but learned behavior that we all take for granted UNTIL we hop on a tandem. On a tandem and in particular one with STI or Ergo levers, new Stokers don't have any form of visual or mental cue -- like moving a shift lever -- that causes them to momentarily "lighten-up" on the pedals when the Captain initiatives a shift. Bar-ends actually do have an advantage in this regard since the Captain's movements when making a bar-end shift are quite noticeable but I believe it's only a short-term advantage as even more subtle cues will eventually be used. Nonetheless, the Stoker being disconnected from the mental and physical process of shifting the gears is where the troubles begin with respect to executing smooth shifts on a tandem. The most troublesome and obvious place where this usually happens with new team is on hills and most often when teams try to shift into granny just a tad later than they should have. In this scenario there is just too much torque on the chain in the 42x28 or 42x34 for the derailleur's spring to pull it off the middle ring. Likewise, sometimes the rear derailleur will have a hard time moving a chain up when it's too loaded up but Captain's tend to apply brute force to overcome the drag and force the chain up to the larger cog.
So, if any of this sounds familiar here's what you do. You use audible commands to call out shifts (e.g., OK sweetie, "Shifting" or "Lighten-up") for a while and make a point to shift earlier, i.e., when your cadence drops to 70 instead of 65 or 60. If you make a habit of doing this uniformly most Stokers will begin to develop the ability to intuitively know when you -- as their Captain -- will shift based on the terrain, your RPM and the amount of effort you're putting in as a team. However, what is more important is that they will also learn to feel YOU shifting through the pedals, recalling from my earlier comment that most of us do in fact alter our pedal pressure slightly when we shift. In fact, what seems to happen is that Stokers intuitively learn to "soft pedal" enough for Captain's to regain the feeling that they are making effortless shifts because they can once again intuitively "soft pedal" through the shift like they do on a single bike: only now, it works because the Stoker has reduced their pedal pressure enough to allow it to effective.
The other place this learned team soft-pedal technque works is for moving back up from the middle ring to the big ring on a tandem. By their very nature, tandems that use wide range chain rings (e.g., 54-42-28) sub-obtimize the heck out of front derailleurs by forcing them to work a gear capacity that is sometimes off of the official spec sheet. Therefore, a lot of teams will find that the cranks travel further than average to get the chain to lift from the middle to the big ring (grind, grind, grind, Ka-chunk). If you or anyone else reading this ever experiences this performance issue the soft pedal technique will also allow you to move the chain from the middle to the big ring ring as smoothly as can be (Ka-chunk). Again, you'll have to start off using an audible "request" to your Stoker to "lighten up" until it becomes intuitive via the pedals.
Originally posted by Davet
Bar-cons, in my mind, seem to be a simple no-sweat shifting system. The shift levers sort of let you know what ring/cog you're in, and you can shift down, or up, a bunch of gears at a time. And trimming is a cinch. The only downside I can see is the necessity of taking my hands from whatever position they are in, to shift.
Bar-ends have their pros and cons, as do STI and Ergo. There definitely is the visual gear position indicator aspect to them along with the relatively simple and bomb-proof design. However, Shimano made in-line gear position indicators that are still available, it's relatively easy to home-make gear position indicators that go on your shift cables at the down tube, and at the high-end Flight Deck and Campy's ErgoBrain both provide very nifty data regarding the position of your chain. Well, and since you're riding a tandem you also have one other "gear position indicator" on board and just behind you called your Stoker. As for gear selection and shift range, trimming on Ergo's is as effective as bar-ends and STI has gotten better since they increased the number of stops from 3 to 5. As for covering the cassette with a sweeping gear change, Ergo does match bar-ends in their ability to shift up or down through nearly the entire cassette in a single sweep. STI, on the other hand, does have its limitations but don't loose sight of "practical utility" and real-world data: pros seem to be able to "get by" with single click upshifts and the number of cogs that can be downshifted in a single sweep (I'm pretty sure it's 3 and 3x3=9). The big difference IS hand-on brake hood control and that's a very useful thing to have if you are an aggressive team that wants to run with the "big dogs". Out of the saddle shifts are not practical (if even possible without undue risk) on downtube or bar-end shifters, whereas they have become the norm for STI and Ergo users.
Ultimately, as I mentioned before, the pro-con discussions on bar-end vs STI vs Ergo are all meaningless since the choice must ultimately be made based on what's best for each user. Hey, I'm glad Lance likes STI... but Ergo just works better for me.
Originally posted by Davet
The tandem seems to take more thought and planning in it's ride and operation, therefore my consideration of bar-con shifting was to make it (supposedly) simpler and easier.
Ultimately, familiarity is what you'll want between your tandem and the single bikes you ride the most. As much as I really enjoyed my SunTour Superbe Pro friction shift grouppo, life was never so confusing as when I jumped from my older road bikes to a newer one with STI to our first tandem that was fitted with Sachs Ergo/Shimano XTR. I reached a point where I didn't know what was up or down on the STI or the downtube shifters and ultimately decided to go with Ergo since it fit my small hands the best and seemed the most idiot proof (right or left thumb down = chain moves "down" to smaller rings / right or left index finger in = chain moves "up" to bigger rings).
Mind you, this isn't a pitch for Ergo levers.... it's just an anecdotal story of my search for what was 'best for me' and the most important thing was making sure I didn't have to re-learn shifting as I moved from bike to bike to tandem.
Hope this helps and, if not, that it was at least entertaining/interesting reading. If I totally missed your shifting issues please provide me with some additional details and I'll take another whack at it.
P.S. FWIW: I've had bar-end shifters on single touring bikes and our first tandem came with the bar-end shifters. But you say, "Hey - Wait a minute. Not two paragraphs ago you said your first tandem was fitted with Sachs Ergo?". Yes, it did have bar-end shifters... for exactly two rides. Hence the Sachs Ergo shifters which, in 1996 were the only OEM integrated shifters that could be used with a front triple chain ring. Shimano introduced 105 triples in 1997/8.