Swapping Casette

mccutchie

Hey guys,

I'm trying something new for me, i've some big tests coming up, endurance cycling. I currently ride shimano ultegra 6700 11-25. For what i'm doing next over very hilly terrain i'm switching to the same model cassette but 11-28.
I'm wondering will i need a different chain, or should my current one be ok, size wise etc. Current chain is only 2 months old.

Cheers,
Mccutchie

bobgfish

Same chain will work provided it's not too worn. Use a chain checker. I find that after about 2500Km a chain is poked and needs replacement. I have found that sometimes a new chain on a worn cassttte will skip it's first ride or two as it beds in to the most worn sprockets on the back.

Flamez

I did the same and the rear short mech and existing chain was fine.

fludey

I have just done the same with 53/39 up front and gone from 11-25 to 11-28 and the chain is just fine on short cage rear deraileur.
But as said above just check the stretch on the chain dont wanna ruin your new cassette.

buckmulligan

Not that I want to disagree with everyone else but...

Assuming your chain was the correct length originally, changing up to a 11-28 may mean that your chain is too short for some big-big combos. I know it's not a combination that you want to be using, but if you have a have a brain-spasm and end on the big ring up front and one of the biggest two on the back, you could easily damage your rear derailleur.

Have a read of this thread, it explains the maths of getting the right derailleur and chain length in a very simple way!

If you measure it and it comes up short, I'd definitely add a couple of spare links, better to be safe than sorry.