Shimano Hollowtech/Octalink Crank Arm Shortening |
175mm becomes 154mm 172.5mm becomes 151.5mm 170mm becomes 149mm 165mm becomes 144mm | |
Hollowtech FC-5501, 5502, 5504 and 5505 105s and 6500 series Ultegra are the only ones that can be shortened Due to the way these thing are made, there will be some variation in how close the end of the tunnel is in relation to the end of the crank. They are forged around a steel tongue. The pedal end is fatter on the outside. Then the tongue is pulled out and the end is stomped flat, closing the tunnel. A lot of hand shaping and finishing must be required to make them look so nice, because they really aren't that symmetrical.
175mm or 170mm
I've never had a problem shortening a 175 or 170 by 21 or 22mm. (Not so far anyway, but it certainly could happen.)
165mm or 172.5mm
Out of 3 sets of 172.5 I did tap into the tunnel on 1 arm at 150.5. Since then, I've done about 20 sets at 151.5mm
and just barely tapped into the tunnel once. Based on this "Too small to be statistically valid" sample, I'll leave it up to you to decide if it's worth taking the chance.
If I tap into a tunnel, because it is unusually long on your arms, I don't charge enough to be responsible for replacement.
I will NOT shorten Shimano 105 FC-5503 or FC-5500 See photo at top for Model # Location on back of crankarm.
Hollowtech MTB cranks
Hollowtech II hollow two piece cranks No way, not even close. |