Ultegra 6800 switching from 11-28 to 11-32 cassette
 

Hello,

I am switching my rear cassette and dérailleur for better steep hill climbing. I am going to a 32t from 28. Do I need to lengthen the chain?

Thank you,

Juan

Yes. Use this to calculate how long your chain should be:

Javascript Bicycle Chain Length Calculator

That said, you can probably get away with not doing it, but your chain will be about an inch too short.

While Shimano recommends the mid range derailleur for 11-32, there are folks that have used the standard derailleur for 11-32. You might try the change without a new derailleur, but that's another thread I guess. My 11-32 is the first compact I have owned, preferring triples to maintain a close enough ratio for my liking. With 11 speed I'm fine with a compact double on my wide ranging rear. Thanks for the link.

And then he'll be the guy on here complaining that his shifting isn't working right.

Follow the specs, get the 6800 GS RD, get a new chain and set it to the right length and it will work perfectly every time OR try to screw with it doing it some other way to cut corners and save a few bucks. You decide.

Agreed. This is why I started my reply "yes" to his question! :D

IF your chain is properly sized for the 28T cog, you'll be 1" too short.
What I would do is-
Shift to Big:Big
Take 2 "skinny" screw drivers and insert in a long section of chain that is accessible.
Pull the 2 screw drivers together and see how much slack you can generate.
IF 2", your chain is long enough. IF less, you need a longer chain.

As far as the RDER handling things? Ya got me.