Cycling

The Trouble With Triples

I’ve learned more about bike mechanics in the last two months than in the rest of the four or five years that I’ve been tinkering with them. Restoring an old Peugeot 10-speed to use as my one bike to do everything has been an education and  a frustration. A broken spoke within the first ten miles has been the only mechanical failure, but this meant having to remove the freewheel to replace the spoke, which of course meant purchasing a freewheel removal tool designed for old French wheels.

Niggles aside, the bike is proving to be a fine all-weather daily commuter and mini-tourer. The old carbolite frame and plush 38c tyres are a joy to ride on, and contrary to all expectations I’m averaging much higher speeds on my old 14kg Pug than I did on my modern racing bike. In part this is down to the gearing; a large chainring with just 42 teeth allows me to keep spinning at a higher cadence for long periods, which helps to sustain a higher average speed. Compared to the 50t or 52t big ring on more modern racing bikes this makes pedalling far more efficient over time, and much less tiring. Spinning really is winning.

I think a more upright riding position is also partly the reason that I can ride faster for longer. This may sound counter-intuitive, but the relatively high position of the handlebars compared to a bike with modern racing geometry means a shorter reach to the drops, less neck and shoulder pain when riding stretched out, and therefore more time spent riding in the most aerodynamic position. You can’t get as aero on a thirty year old tourer as you can on a contemporary racer of course, but if you can only ride with a slammed stem and bars for a short time before discomfort sets in and you have to sit upright, you really won’t be that much faster overall. Retrogrouch has a fascinating insight into the differences between older and newer bike geometries that touches on this.

This tends to support my theory that the current race-oriented bike market tends to sell bikes that have too high gearing for the reality of daily use by ordinary cyclists who aren’t trying to win the Tour de France, and that people are often encouraged to buy bikes with aggressive geometries that don’t really suit them in the name of speed. You only need to peruse a few cycling forums to see the position-related aches and pains that people suffer from to see that this might be the case.

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There is one niggling feature with my new steed though. I switched from the original 52-42 double crankset to a custom 42-34-28 triple setup for a more comfortable range of gears. Try as I might though, the Suntour road derailleur I bought for the job is just a fraction too long. When I try to shift to the inner 28t chainring, the derailleur cage catches on the chainstay. I’ve bodged a fix for this by locating the derailleur higher above the crankset (see picture), but this makes for poorer shifting and means I can’t use the granny ring at all because the cage just isn’t low enough to catch the chain.

I considered using a bottom bracket that had a longer spindle but this wasn’t really satisfactory. Instead I’ve ordered a Shimano Alivio mountain bike derailleur designed for a chainring no larger than 42t. It is smaller than the Suntour one (which was designed for 48t) and so the cage shouldn’t catch on the chainstay. This weekend’s project is to install the new derailleur and get the triple set-up working correctly so I can begin to think about tackling some of the local hills.

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