The New Old Crank Set

As we neared the end of the year, some issues with my bike started cropping up. Because I am me, I immediately diagnosed them as problems with the front derailleur. Because I am me, my diagnosis was 100 percent wrong.

The problem was a noise — a sort of a creak — that started whenever I pedaled in the small chain ring. When I shifted to the big ring, it was quiet. On a club ride two weekends ago, I spent as much time as possible in the big ring, just to keep from hearing the noise. But some hills were involved in that ride, and riders near me were treated to a “creak — creak — creak” noise whenever I applied power or started climbing.

I dropped it off with our club’s bike mechanic, who was surprised to be seeing me again so soon. He’d just done some work on my rear derailleur. The next day, he sent me his verdict: bad crank arm and bottom bracket. My mind  brought up memories of  an incident that happened on a New Year’s Day ride. My left crank arm fell off. Having to tighten it before each ride after that got old fast, so I got some blue Loc-Tite and smeared it into place. Once it cured, no more crank arm problems.

Don's crank set.

I was pleased about that, because I liked this setup. Guest blogger Don Blount had sent me the crank set after I’d posted about needing 172.5 mm cranks instead of the 175s that came with the bike. The shorter crank arms let me deliver more power to the pedals. But it turns out my fix was only temporary, and in the long run it did damage. The bike mech summed it up:

“The noise issue appears to have been started by a degrading crank.  The non-drive crank arm appears to have worked loose over time.  This damaged both the crank arm by wallowing out the splines and, because it allowed for play on the crank, ended up damaging the non-drive bearing on the bottom bracket.”

The only way to fix the problem, he said, was to replace both the crank and bottom bracket. Yech. But I had a solution, sitting right in the garage — the original crank set and bottom bracket that came with the bike.

The original.

He put them on, and I was rolling again the next day.

Because Christmas intervened, and we were out of town for five days, I haven’t ridden it much yet. I have gone out on some short rides with my wife, and really pushed hard today when we did Veloway laps. I will have to lower the seat a bit — maybe not the full 2.5 mm the new cranks have added to my pedal stroke, but enough to keep that twinge away from my knee — and futz with the saddle, because lowering it means I have to put it back a bit, too. Heck, I haven’t had the bike fitted for almost two years. Maybe it’s time to do it right and make an appointment to get it done right.


Click to embiggen.

Christmas was a modest affair around our house. Pat set a low gift expense limit, so neither of us went overboard, but we both got what we wanted. I got some new wool socks, because I like the ones I have so much. But these are truly high-tech socks. They’re even sized for each foot. And they tell you which one, right on the toe. Makes me feel like being in kindergarten again, when we had red ribbons tied to our right shoe so we would be able to learn left from right.


  1. says

    You know, of course, that you can adopt the title “Serious Cyclist” when you are to the point of wearing stuff on your bike out!

    I run 172.5 crank arms on both my single bikes, and the tandem has a 175. I don’t notice any difference when I bounce between them. The only way I know the difference is by measuring and comparing the distance between the saddle and the bottom bracket on the different bikes.

  2. says

    I have so much bike stuff stored in my garage that I pine for a problem so I can use some of it.

    We don’t exchange gifts any more in my house. Instead we adopt a family or sometimes two at the Salvation Army and give them a nice holiday. Like you, we have everything we need.

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