… back in my day …
My bike preferences and tastes were shaped in my bike-shop years around 1980. I like friction shifting, rim brakes with the cable routed out of the top of the brake lever, triple cranks with square-taper spindles, and leather saddles. I think traditional-diameter steel frames look normal and ride great, and wheels with fewer than 36 spokes are only for special applications. In many cases, changes from these designs do not solve any real problems, at least for my needs, and they create new problems of confusing proprietary non-standards and incompatibilities. The main purpose of “innovation” in bike design seems to be change for the sake of change and to manipulate people into buying new bikes in response to the allure of perceived progress, lust for the latest and lightest, and creating barriers to fixing the old bike.
This is a story about how a repair that should be routine gets complicated by changing industry practices.
When I converted the Brown Bike to 650b wheels in 2007, I installed a Harris Cyclery 13-34 cassette and new 26-42-50 chainrings on the existing TA crank. This made for a nice wide-range step-and-a-half sequence as described in a previous post. Eventually, the Brown Bike was replaced by the new Rohloff bike for utility and touring. Some of the parts were transferred from the Brown Bike to the Rohloff bike, but the rear wheel, cassette, and crank from the Brown Bike ended up on the new rando/sport bike.
Since installing this drive train in 2007, I had replaced chains many times, but the cassette had about 14,000 miles on it when the rando bike hit the road in December 2016. When it became time to replace the chain again, two years and 4,000 miles later, it was clear that the cassette was shot – the new chain was very noisy, shifting was terrible, and it felt about to skip.
It quickly became evident that a direct replacement for the cassette was not be had. Harris no longer assembled custom cassettes.
But a greater vexation was that the 13-tooth smallest cog appears to be extinct — 11 teeth seems to be the default. From a practical perspective, the lack of a 13 would mean that I need a smaller chainring on the front to maintain a useful top gear (no more than about 100 inches). Furthermore, a new middle ring would be required to keep the step-and-a-half-with-granny gearing sequence that I like. In addition to this immediate practical consideration, I think the trend towards smaller cogs is bad because smaller cogs are less efficient for power transfer and they wear more rapidly.
The TA Pro 5 vis (usually referred to as “Cyclotouriste”) crank transferred from the Brown Bike has seen use and abuse for many miles and many years. Aluminum has a finite fatigue life, so I decided that it might be prudent to retire the crank from long-distance service rather than purchase new chainrings for it. The crank may go back on a bike intended for short trips, since rings are still readily available (Peter White seems to have the best selection), but I don’t want the crank to fail on a long ride far from assistance.
So I now have two major components to research and purchase: a cassette to replace the custom cassette that is no longer available, and a replacement crank and appropriate chainrings.
I eliminated some “update” options. If I converted to a 10- or 11-speed cassette, I would also need to replace the rear wheel (the hub is limited to 9 speeds) and the shifters (really intended for 7-speed so the cable pull is maxed out with 9). If I chose a wide-range cassette (like 11-42), I would still need new double chainrings to get the range I need and I would also need a new rear derailleur. Depending on the specifics, the cost of these changes could be significant, but I like the current arrangement and these changes would not add to the functionality of the bike.
I chose a Shimano XT 11-34 cassette and replaced the 11 with a 12. I seriously considered an IRD, but it does not work well for step-and-a-half gearing because the cogs are not sized with consistent percentages between steps.
I wanted a crank that would last, forged of good aluminum alloy, square taper bottom bracket, real triple (rather than triplizer chain ring), a reasonable Q factor, and with readily available chainrings. After much deliberation, I chose a Rivendell Silver, cold forged of 7075 T6, with standard 110/74 bolt circle diameters. I am not wild about the chunky styling, but it meets all the technical requirements. The rings that come with the crank aren’t quite what I needed, so I purchased a two Stronglight rings (38 and 46) from Peter White.
When I attempted to install the crank, I discovered that the newish 126 mm SKF bottom bracket spindle on the bike was much too long (Riv warned me, but I didn’t believe them). After trying a few other spindle lengths, I confirmed that a 107 mm BB (previously used with a single chainring on the 7-speed IGH Schwinn) was the appropriate width, even for this triple. This old BB is basically sound but it has a lot of miles on it and will need to replaced soon.
One final complication: With the 46-tooth large chainring, the front derailleur could not be mounted low enough because the end of the derailleur runs into the chain stay. It still shifted reasonably well but dumped the chain with unacceptable frequency. I did not think a derailleur designed for two chainrings would work well because it is still dealing with a big range of chainring sizes. My solution was to cut down an IRD triple derailleur that I had in the parts bucket.
I am happy with the result, though it is not perfect. I have 21 usable gears with one or two near duplicates and a range of 18 to 100 gear inches (1.5 to 8 meters). But I would have been happier I had only needed a new cassette.
Rolling and tumbling 