Originally Posted by
Princess_Allez
The drivetrain is all fairly new. It has ~1500 miles on it. It's all the factory stuff that came on my 2018 Specialized Allez Sprint.
So the takeaway here is that I can go 11-30 without changing chain or rear mech, but if I want to go 32 or 34, then it would require a new chain and mech?
That's not quite what was said. Given that we don't know how your current chain length was measured, your drivetrain might be at its limit with your current 28 sprocket. A 30 sprocket will be within the chain wrap capacity of your current RD, so you know that you're not going to need a new RD if your switch cassettes, but again -
this is a separate issue from chain length, which is the one individual variable about which we know nothing. You will not need a new RD, and you may not need new chain. Easiest thing to do is put your drivetrain on large/large and confirm that your RD is not at its limit. If it still has a bit more forward travel, you likely will get away with your current chain