dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal7/29/14 11:05 AM |
Since we're measuring top tube length at the actual height of the top tube,
the effect of a 1-degree change (going from 73 to 74 degrees) is 0.9cm for each degree, assuming a frame size near 60cm (x=55cm vertical).
Or roughly 1.1 degree for each cm of effective top tube length change.
Head tube angle also plays it's part with respect to fit in that a very relaxed head tube angle may not permit such a long stem to be fitted without causing "steering heave" when riding out of the saddle.
Inversely, a steep head tube angle usually results in "flighty steering" if the stem is on the short side, and made worse by a taller handlebar height.
Moral of story here might be to not ride too large of a quick-steering racing frame or too small of a slow-steering cyclocross frame, as in both cases the stem length options won't correct the fit without handling consequences.
Unless, that is, the rider doesn't mind a very-forward or very-rearward saddle position, respectively, for each of those extremes.
As an example, this one worked out well, at least for hard-charging ~shorter rides, simply by moving the saddle forward. This frame has steep angles but the 120mm stem that it came equipped with calms it nicely:
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