On Sat, 28 Apr 2007 18:06:27 GMT, still me <
[email protected]> may
have said:
>Why don't we see more variation in crank lengths?
Lack of demand, mostly.
>Frames commonly vary form 53 to 62cm, but cranks only vary from 165 to
>172.5, maybe 175 (commonly anyway).
IME, 175 is more common than 165, and 170 comes in a strong second.
What's often lamented is the difficulty of finding a 180 or longer
crank, as many tall riders would prefer one. (Yes, *some* cranks can
be had in 180 and longer, but the prices are usually quite steep
unless you can use a BMX crank...in which case you're going to find
the longer sizes readily available.)
>Are people's bodies proportioned such that the crank lengths don't
>need to vary - or is this just a cheaper way out for manufacturers?
I do not know if any valid research has been conducted to determine if
taller or longer-legged riders would benefit from a longer crank.
There has been discussion of the disproportionality, but I haven't
followed the technical end closely. If I could afford a 185 or 190
crank for one of my rides, I'd have at least a personal opinion to
offer, but I haven't found one that's within my budget as yet.
Although it can be postulated that manufacturers benefit from limited
optional characteristics in a profit, they also benefit from increased
sales of a product that is able to be fine-tuned by replacement of a
component to achieve a better match to the user's requirements. I
doubt that the component makers are the problem in this instance.
>(I
>se the problem of BB height restricting the upper end).
Not as big of a problem as it might seem, really.
>I know little about anatomical proportions, but it seems like the guy
>on the 53cm frame will have much shorter legs (typically) and need a
>much shorter crank than the guy on a 63cm frame.
Logic would seem to dictate that this should be true, but logic is a
little tweeting bird, chirping in a meadow. Logic is wreath of pretty
flowers that smell bad. OTOH, can either the faceless monolitic
corporate entities or the often-misinformed user base be trusted to
provide impartial and accurate ansers to this question either? I
think not.
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