Originally Posted by
xnihilo
Gonna replace my 12-23 with a 12-26. Will I have to change the chain for the extra 3 teeth? Talkin' about a Cannondale R1000 Ultegra if that means anything.
You have 2 concerns
1) Correct chain length that won't explode your derailleur in the big/big combo
2) Current chain wear
If #1 happens then you're in for a nice repair bill. If #2 happens then you're in for some new dental work.