Shorter crank, new saddle position?
10-11-07, 12:41 PM
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Climbing Above It All
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Shorter crank, new saddle position?
I just swapped out my 177.5 crank for a compact 175 for the winter. I need to adjust my saddle to compensate for the difference in cranks. Should I first move the saddle back 2.5 mm then measure from the BB to the same place on the saddle for height or, Move the saddle to the proper height first then check for fore/aft placement? I had the saddle dialed in with the old crank, I hope it doesn't take long to get it right with the new compact crank.
10-11-07, 01:10 PM
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Many people lower their saddles during the winter to account for thicker, warmer clothes. Shortening your cranks should have same effect.
10-11-07, 01:19 PM
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That won't really apply to me cause I wear bibs or shorts through the winter with knee/leg warmers. It never gets that cold here. The few days it does I just ride the trainer.
10-11-07, 01:24 PM
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I would ride it first and see if there is actually that much of descrepency between the two sizes of the cranks
I would not touch the fore/aft as I believe the only thing you really need to do is lower the saddle maybe 1/10 if that is even necessary.
I would not touch the fore/aft as I believe the only thing you really need to do is lower the saddle maybe 1/10 if that is even necessary.
10-11-07, 02:35 PM
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Yeah, I went for a quick ride and ended up raising the saddle height maybe 2mm. Didn't touch the fore/aft at all. Feels pretty good but of course time will tell. It's so close and not that big a change. I remember going from 175 to 177.5 and could feel the extra length. But two weeks ago I did an extended test ride on a Tarmac with 175 cranks and it felt fine. So it is probably not much to worry about. Thanks.
10-11-07, 02:51 PM
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Yeah, 2.5mm, is almost certainly not enough to matter, but technically, different length cranks will move the spindle position used for KOPS. Going from 175mm to 170mm cranks will move the spindle back 5mm - again I don't know if that's enough to matter.
Seat height shouldn't change at all. If anything, you might want to raise the seat if you're using shorter cranks, as otherwise your legs don't extend as much as before.
Seat height shouldn't change at all. If anything, you might want to raise the seat if you're using shorter cranks, as otherwise your legs don't extend as much as before.
