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Slowtwitch fit formulas . . .

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Slowtwitch fit formulas . . .

Old 12-18-15, 06:32 PM
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Slowtwitch fit formulas . . .

Anyone here try using those formulas Slowtwitch uses for bike fitting? They are based upon saddle height, whereby:
Saddle setback = 9% SH
Bar drop = 11% SH
Bar reach = 75% SH
(There are some minor adjustments, adding or subtracting a few mm, so this is simplified.) After doing the calculations, I was kind of shocked at the results. The fore/aft would put my knee about 3 - 4 cm ahead of the pedal axle, and the reach and bar drop are 4 - 6 cm beyond the point where my power drops off significantly. I realize these are starting points or averages -- or at least I HOPE they are! -- but still. Anyone get fitted by them? (I think some of the Guru fitters use it. I've had 2 Guru fittings, neither of which was particularly comfortable or efficient . . . seemed to be a similar too-far-forward/too-long-reach setup. Or, are they geared towards pro racers?)
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Old 12-19-15, 07:13 AM
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Hmmm, applying the percentages to my saddle height puts the numbers just about dead on to my setup. I've never had a professional fit just the advice of a long time racer friend and listening to my body.
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Old 12-19-15, 09:00 AM
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Since my current position is so far from those recommendations, does that mean my body just needs time to adapt to that kind of fit? Since its the "off season" now, guess I could set up my indoor trainer that way, and see if I get "used to it" by the time spring comes (both in terms of comfort and power). Or, does my much shorter than normal torso prevent me from being efficient in such a position?
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Old 12-19-15, 10:41 AM
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I think those numbers are still subject to the caveat that it depends on your proportions. For instance: I have long legs and a short torso, so the reach calculation is about 5cm too long for me. ( looks like it would actually have me on a 56, rather than what I am riding, a 52. A 54 is actually a little too big for me, so a 56 would be very uncomfortable.)
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Old 12-19-15, 09:52 PM
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The first comprehensive fit-by-numbers system, the Fit Kit, was introduced in the early 1980s. It was a lot more comprehensive than this, and was still found wanting. Still, it was a starting point. We've come a lot farther in 35 years.
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Old 12-30-15, 08:04 PM
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You sure don't want everyone's reach set at a fixed proportion of their leg length. That's just silly. Drop, maybe I could see.
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Old 12-31-15, 02:09 AM
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Isn't slowtwitch oriented toward TT bike fit? Are you riding a road or TT bike?
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