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Triple vs Double and fit
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Every year I rack the training/race bike, 175's double, and go to work on the trainer bike, 172.5 and a triple. Every year I get the same experience, 1) I can spin those 172.5's with little effort. 2) It takes a long time to transition back to the other bike -- feels like a huge dead spot at the top of the stroke. Both are beam bikes. No obvious bouncing during the spring but it takes nearly a month before I get comfortable on the regular bike. Subjectively it feels like I want the triple back...it just feels better being "wider." Historically I've assumed that it was the 172.5's that enabled me to spin eaiser. Now I wonder if its the little extra width the triple affords me that actually may make me more efficient because I'm more comfortable. Thoughts?
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Re: Triple vs Double and fit [Chappy] [ In reply to ]
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My guess is that you should stick with the 172.5 cranks. Why go to a longer crank? Maybe even the 172.5 is too big. Tell us more.

but then I use 165s with my sawed off legs, so what do I know?
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Re: Triple vs Double and fit [ajfranke] [ In reply to ]
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Fit guy, whom I trust, says 175's was the way to go 2 years ago when he built the current bike. As I recall the decision was based on foot length (13), leg length discrepency(?), and strength. Inseam is 31.5. Long torso. He's seen me a number of times since and from his vantage point everything looks good, and acknowledges the transition period in the spring will feel awkward. That I have a IM focus going on also has us leaning towards the 175's. I think the crank length is something to consider I also wonder about how the width of one's pelvis might factor into the mix. I'm fairly wide and wonder if THAT might be a bigger factor in the triple feeling more comfortable. It would seem to me there ought to be an optimal width of BB-Crankset for any of us, one where we are the most comfortable and generate the most power.(?)
Last edited by: Chappy: Dec 31, 03 15:33
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Re: Triple vs Double and fit [Chappy] [ In reply to ]
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Quote:
Fit guy, whom I trust, says 175's was the way to go 2 years ago when he built the current bike.


All due respect to the fit guy, but nobody is that smart. Crank length is a self-selected thing, like shoes and gloves. There is no biomechanical "correct" length (and plenty of excercise phys PhD candidates have nearly died trying to find a formula for one). Do you feel better on the 172.5's? Then that's your crank length. Period. End of discussion.

As for width -- I doubt it. Try the shorter cranks on your race bike for a while (just put the triple ones on there without the granny ring). I'm betting you'll be fine. I ride a triple road bike and a double tri bike, and I cannot tell the slightest difference going back and forth between them (both have the same crank lengths).
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