Choosing Appropriate Gearing for Cycling

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09/23/2005| 0 comments
by Travis Woodruff

Choosing Appropriate Gearing for Cycling

We?ve all seen Lance Armstrong spin his trademark high cadence up the mountains while his counterparts turn bigger gears.

roads. It has become common for bike manufacturers to spec entry-level road bikes or touring bikes with triple chainrings. Cyclists doing long rides or tours often take advantage of the triple gearing as it is ideal for vastly changing terrain, as well as giving the legs a break after many hours or days in the saddle. A triple chainring is also a great option for average riders who don't want to mash 40-50 RPMs up hills. Triple chainring setups have had a negative stigma attached to them, as some riders think it will make them appear "weak", but they've become more acceptable as people realize that the benefits outweigh the grief that they may receive from their riding partners. The added weight and seeming complexity of a triple chainring setup may be the only things preventing its further popularity.

 

A relatively new alternative is the compact crank. Using a double chainring configuration with fewer teeth per ring, riders are able to capitalize on new gear ranges. Compact cranks are finally coming to the forefront as a viable option for riders of all abilities to consider. Anyone living in mountainous or hilly terrain should give serious thought to the benefits of a compact crankset. Rather than using the standard 130mm Bolt Circle Diameter (BCD), compact cranks have a smaller 110mm BCD that allows for smaller chainrings. Compact cranks commonly have a 50 tooth large ring mated with a 34 or 36 tooth inner ring. These smaller rings allow for lower gearing and a higher climbing cadence. With this setup you not only have an additional lower gear, but also a higher gear (when compared to a traditional set up of a 53/39 crankset with a 12-25 cassette). This wider effective gear range is accomplished with fewer duplicate gears. Riders as well as racers are beginning to appreciate the gearing of a compact crank. Only very powerful sprinters or criterium racers that routinely use the 53x11 will be hampered by the having just 50 teeth on the big ring; for most racers this is not a concern. A 53x11 gear will give you 126.6 gear inches when using a 175mm crank and 23mm tires on 700c wheels. This is slightly larger than the 119.5 gear inches of a 50x11. We should also consider the difference in gearing at the low end. A standard 39x23 yields 44.6 gear inches while the 34x23 offers a gear of 38.8 inches. If you switch to a compact crank, but leave your same cassette you'll essentially lose your biggest gear, but gain two lower gears.

Of course, you can simply swap out your rear cassette to give yourself easier gearing options. Your cassette will likely have cogs of 11 or 12 teeth ranging up to cogs of 21, 23, 25, or 27 teeth. Standard cassettes are usually a 12-23 or 12-25. Switching to a larger cassette could be the most cost effective way to achieve a suitable climbing cadence. A 12-25 or 12-27 cassette might make all the difference you need in achieving optimal gearing that allows for

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