Originally Posted by WhyFi

Maybe, but not likely. The most common sizing method for road, and what Shimano recommends, is big/big + 2; this would leave your chain too short for the additional teeth.



Most likely yes on the new chain, not necessarily on the new RD - I haven't tried it, but many people seem to get on just fine when exceeding Shimano's largest cog spec by two teeth (check to see what the official spec is). Alternatively, you might be able to use something like a Wolftooth Road Link as long as the RD can handle the wrap.