# Crank Arm Length to Saddle Height



## loneclimber (Feb 2, 2011)

I recently went from a 172.5 to 170 crank set. How much do I need to adjust my saddle position in terms of height and fore/aft.


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## wim (Feb 28, 2005)

If you want to re-establish your old knee angle at the crank bottom dead center, you need to raise your saddle 2.5 mm. Technically, you should also move your saddle forward about 1 mm. But because that's such a small amount, I wouldn't bother.


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