Newsletter - 2004 Archive

BC Randonneurs Cycling Club

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Getting Fixed by Ron Penner Life is funny sometimes: When I first got the itch to attempt to ride fixed gear, I went into it the same way I do with all things bicycle. Spend a lot of time thinking about it, reading about it on the web, then finally, jump in and give it a shot. This sensible attitude did not help me avoid buying a Softride frame and deciding I really didn't like bouncing around on a beam while riding, but in general it has worked out pretty well. So, for fixed gear there were initially two issues. (1) How do I turn my older GT with vertical dropouts into a fixed gear bicycle, and (2) if I only have one gear to choose from, what exact gear should I choose? I checked out the famous Sheldon Brown website and he suggested in his articles that there were a few ways to make the conversion. The first attempt with a "Surly Fixxer" failed because I got the lock nuts wrong and ended up with a seized hub half way to work one morning. The second attempt, last weekend, with a "White Industries (ENO) Eccentric" rear hub, would end up doing the trick. Next issue: gearing. After attempting to ride on my geared bike in known configurations, I settled on approximately 70 gear inches as a good compromise for a somewhat hilly commute. At that ratio, I was more concerned about spinning out of control on the downhills than having to walk on the uphills. Sheldon Brown also mentioned that chain tension would be an issue for vertical dropouts and I would have limited gear combinations that would work. I bought some half chain-links to improve my chances of getting a good fit. I found some online chain length calculators that helped me determine a good combination: 39 x 15 (71.7 gear inches) should allow me to use the existing inner ring and give me a decent chain line. Then I remembered that my current crankset on the GT was an old Shimano Biopace. I generally don't notice it, so I have left it alone till now. Back to Sheldon Brown's web site. Yes, he says, you can do it, but it puts even more importance on getting the chain tension right, because it will vary through the pedal cycle. Yikes. Another wrench in the gears. Would this work at all? Well, last weekend the rear wheel with the eccentric hub was finished, I put the whole thing together and was able to get a chain tension that worked. I took the bike out for a short test ride and found the experience good enough to be worth attempting the weekly commute. There were minor grinding noises, but I knew the chain and chain ring were old and would have to be replaced soon. Well, one week of commuting (about 150 km) told me that I like riding fixed, but that my gear choice was a bit ambitious! I was expecting to spin freely on the flats, work hard on the uphills and spin like a crazy man on the downhills. I found that the uphills were REALLY hard, the downhills were not as bad as I thought and on the flats I was not doing the desired 85 - 90 rpm. I thought, am I getting old (hard to admit but possible), or not in as good a shape as I think (even harder to admit)? Well, I decided this past weekend it was time to replace the oval chain ring with a round one, and put a new chain on as well. That should hold things for the winter. I got the new 39, and new SRAM chain (love that power-link). Now here's the funny part (finally). Last night, as I was pulling off the old biopace chain ring, I happened to look at it instead of just throwing it away. Lo and behold, it's a 42! Suddenly, the gearing that I was complaining about was 77.2 gear inches. No wonder. Suddenly I am not aging too quickly. This morning I found myself busy going down River Road in Richmond doing a good and proper 90 rpm on the pedals, grinning from ear to ear and thinking happy thoughts about tonight's hill climb on the way home. It is always strange to me how much of our sport (or any sport I suppose) is mental. How can an 8% change in gearing make for such a complete change in attitude? November 29, 2004 _