Rear Deraileur Cable Shimano 105

[cny-man]

A shorter cable will not affect shifting at all - the derailleur does not know how much cable extends beyond the clamp. Further, it cannot be the cable alone, as that would not affect both ends of the range. If too tight you may not reach the small cog, if too loose you may not reach the large one.

The limit screws on a new derailleur are going to need adjustment, period. They don't know at the factory the exact setup you (or anyone else) has. Luckily the limit screw are intentionally set tight so that you don't just slap on the derailleur and shift into the spokes.

So the first step is to adjust the limits, which is best done separately from the cable tension. Check the above tutorial, partktool.com/blog or sheldonbrown.com for adjustment procedure, but if it's not specified adjust the outer adjustment with the cable tension loose, and adjust the inner limit by pulling on the cable like a bowstring instead of using the lever. Then proceed to adjusting tension for the in-between cogs. If you are not confident in doing the above then take it to a shop or co-op for assistance.