Originally Posted by
HTupolev
I dunno, things like "rub" get mentioned a lot which makes no sense in a friction-shifted context. And if you get much before 1990, there's almost nothing triple-specific going on, since neither shift gates nor interestingly-sculpted front derailleurs existed.
I certainly don't see how the friction shifting itself would be a culprit. In my experience, flawless indexed front shifting is generally still flawless when used with a friction shifter, and friction shifting can allow all kinds of crazy setups that would never work with indexed shifters to behave somewhat reasonably. Like half-step-plus-granny arrangements, or those absurdly wide-range doubles like 44-20 that "shift fine" according to the people who use them.
I wasn't thinking in terms of "rub" but in the lack of "snappiness" that people complain about with triples. Old friction systems with flat rings were a bit more balky than more modern index systems.
By the way, I'm one of those people with what most would consider a crazy set up like a 44/34/20 for mountain biking and a 48/36/20 for a touring bike. But I'm using index systems on both mountain and road bikes. Shifts are never a problem in any situation I've run across.
Originally Posted by
HTupolev
II'm wonder how much the shift ramps have to do with it, given the typically small size of shifts on triples. I've got multiple unramped triple setups in my stable that shift flawlessly.
Ramps are also only a consideration when a factory-standard gear combo is being used; unmatched shift gates in custom setups don't seem to accomplish much of anything in my experience.
I think the shift ramps help tremendously. Gone are the days of a lot of clattering to get the chain from the middle ring to the outer ring. Doubles clattered just as much but the fog of nostalgia clouds people's memories.
Originally Posted by
HTupolev
IThis probably does matter. One of my drivetrains is running a 1970s Sugino Mighty Tour triple, currently fitted with 52-42-34 chainrings, with a 1970s straight-cage Suntour Cyclone front derailleur. The middle-to-small shift can be a little baulky if the upper run of the chain is kept under high tension.
That's not an issue which actually affects me very much, though... on my ride yesterday I had a moment where I was chasing an ex-pro up a steep hill*, and even there, that front downshift was snappy and clean. Amusingly, I actually had more trouble with my rear shifting: the switch from the 24T to the 28T on my TZ20 freewheel clanked a couple times under the strain before completing.
But, I suppose that it could be a big problem for someone with poor technique, who doesn't shift until the cadence has already badly bottomed out.
*There's a segment that contains the rise that averages about a 4% gradient where we averaged just under 17mph, and his power meter was clocking a sustained 550W on the steep bit, so I was pedaling pretty hard.
Not to say that I'm a particularly strong cyclist... this guy was cruising along at those intensities on a 50-mile ride, I only rode along with him for about 10 minutes. One of many interesting pieces of a whacky 109-mile road adventure.
The failure of the chain to drop from the middle to the inner ring was always a problem in mountain biking. That's why the reverse action front derailer was such a breath of fresh air. Mountain biking is usually done on the edge of that low cadence problem and it's also done on steeper angle trails which slows the cadence even more. There was a real art to shifting soon enough, throwing the shift lever fast enough, easing off on pedal pressure just enough to avoid stalling out
and getting the chain to drop but not drop off completely. I can do it but it would be so much nicer not to have to.