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Replaced crank
Hi I replaced my crank that was 170m to a 175m do i need to replace the derailleur also? the reason im asking is the derailleur would not go to the high gear. if you have any ideas pls let me know thanks
You shouldn't need to replace the derailleur. I just did this swap on my bike and I dropped down to a smaller large gear in the front. I just had to lower the derailleur on the frame and then readjust the high and low limit screws since the new crankset had a little bit more spacing between the gears than the old one.
i tried everything the derailleur wouldn't go all the way out so the chain can go on the larger gear. I released the cable to see if that helped but it did not
changing the crank arm length would not have any effect on the gears unless, you also changed the tooth count on the chainset?
or, the chain line has been affected?
i kept the teeth count the same 42-32-22 was the count
well I just checked it out and my teeth count did change went from 42-34-24 to 42-32-22 do you think that's the problem?
rokee - changing the arm length or the tooth-count that you have now, will not result in the problem you described.

What WILL cause this problem is installing a crankset (other model or brand) that requires a shorter bottom-bracket spindle.

If you did, perchance, replace like with like, just a diff arm length - I would guess that you have a square spindle. The aluminum arms will, over time, distort/ enlarge. This is why we need to check the tightness of the crank arm bolt during a maintenance session.
As they are repeatedly tightened, they move inboard and we compensate by adjusting the Hi limit screw on the drlr. When you install a new crankset of the same, the drlr Hi limit screw must be backed out until the shift will complete.

Make sense?

Wheelies don't pop themselves. (from a QBP fortune cookie)

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