Fact Or Friction?

The more I ride the Cervino, the more I want to keep riding it:

In case you missed it, the Cervino is ostensibly a Nishiki, but it is in fact hiding a small Viner between its stays:


I’m also sorry for the following photo:

You can sort of feel summer zipping up and getting ready for the descent into fall, but in the meantime it’s still hot and I’m getting good use out of the Pearl Izumi Attack Air Jersey and Attack Air Bib Short. The jersey in particular is light and comfortable, and the aggressive name notwithstanding the ensemble has an understated appearance that goes nicely with a classic bike–though I still need to address my shoe situation (or “shoe-tuation”):

Rest assured I’ve already taken several important “steps” (see what I did there?) towards doing so.

Speaking of steps, I’ve also taken a crucial one in preparing for the Classic Cycle 21st Century Friction Shifter Shoot-Out:

This involved mounting the first test derailleur onto the official test bicycle (or “test-cycle”):

I figured I’d go in more-or-less chronological order starting with what I’m assuming is the oldest derailleur, the Shimano Altus LT, which as far as I can tell dates back to the late 1970s and early 1980s:

Here are the specs, via the Disraeligears website:

When this derailleur was current I was riding around on a Schwinn Scrambler with a coaster brake so I have no idea what its intended use was, though it’s probably safe to say it was “geared” (that’s another pun!) more towards so-called “casual” riders than racers. I was also too busy riding off curbs to be measuring rear spacing and counting cogs, but I’m assuming it would most commonly have been found on bikes with 5- or 6-speed freewheels and rear spacing of 120mm to 126mm–and if I’m wrong I have a feeling you won’t be shy about correcting me.

In any case, here we are over 40 years later. Will the Altus LT work on a bike with a bike with 130mm spacing, a 34/50 compact crank, and a 13-29 Campagnolo 10-speed cassette? Here’s the test-cycle as I’ve been riding it, with a short cage 10-speed Shimano 105 5700 rear derailleur. This is the 5700 on the largest cog and smallest chainring:

And here it is on the largest cog and the largest chainring:

Here’s the corresponding shift lever position:

And here’s the weight of the 5700 derailleur:

Weight weenies should note these are not the original pulleys, though I can’t imagine that would meaningfully affect the overall weight. Then again, when you’re a weight weenie any measurable difference is meaningful.

Installation of the Altus LT derailleur went as smoothly as one could reasonably expect given my lack of competence. Throughout the test I will do my best not to change anything that might introduce bias into the overall results, so for that reason I kept the chain filthy. (That said, the test will require me to open and close the chain at least seven times, so I do reserve the right to change the quick link if I begin to question its integrity.) Here it is on the large cog and the small chainring:

And here it is on the large cog and large chainring:

As you can see, its capacity seems sufficient. Its range is also more than sufficient to cover the entire cassette, and when in low gear there appears to be plenty of clearance between the pulley cage and the spokes. (This is a problem I’ve had before when using old derailleurs with newer, wider cassettes.) And here’s the position of the shift lever when in low gear:

The long throw required for the 5700 isn’t at all a problem in practice, but I’d still file this under “improvement.” I should also note that the position of the limit screws as well as the fact that you can look right into the parallelogram and see where they’re sticking out makes adjustment easier than it is on newer derailleurs like the 5700 (not like it’s particularly difficult, but still), though this is somewhat mitigated by the fact that the anchor bolt is a hex bolt and not an Allen bolt. And yes, the Altus AT is a whopping 28 grams heavier:

But that’s only about the weight of a single fancy crabon water bottle cage, and since I don’t have any fancy crabon water bottle cages on the bike I think I can spare the grams.

Okay, so this 40 year-old relic weighs only slightly more than a 10-speed 105 derailleur, has the same range and capacity, and is easier to adjust. How have derailleurs actually improved? Well, as some of you have noted, the newer derailleurs in this test have a “slant parallelogram” design, as you can see here:

The older ones, including the Altus LT, do not:

So for reasons we’ll conveniently not bother with, the newer derailleurs should work better. But there’s also other stuff that makes modern bikes shift better too, like ramped cogs and improved chain design, so we’ll see how much of a difference a slant parallelogram makes on a bike that already has all that other stuff.

But there is one feature the Altus LT has that newer Shimano derailleurs don’t, and that’s a “Centeron Mechanism.” Here’s what that is, according to contemporary Shimano documents via (where else?) the Disraeligears website:

In the pre-SIS, pre-Hyperglide days, this was Shimano’s attempt to make shifting smoother and easier. Here’s the actual mechanism, which you can see doing its thing when you shift, or even when you tighten the anchor bolt:

Of course I won’t be using it with the Centeron shifters for which it was designed, and not having actually ridden the bike yet I have no idea how or even if it will work in practice or what effect it will have. It was also present in the first iteration of XT (and I’ll of course be testing one of those, too) but the mechanism was gone by the time SIS (that’s indexing) came in–though as I understand it the underlying concept lives on in Shimano’s floating pulley, which I believe are (or at least were) also called Centeron. In any case, if nothing else it’s noteworthy as one of Shimano’s last big attempts at shifting refinement before the SIS/Hyperglide era.

Anyway, everything checks out pre-flight, so I’ll let you know how it does out on the road.

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