Originally Posted by
timdow
If you use an on the bike method, without running chain through rear derailleur, wrap chain around big ring and biggest cog, then add two links. I have not used mullet cassettes though.... I just read online that this method is only good for 36T and under.
If it is not exact, I personally err on the short side for the chain as I would never be in big ring big cog combo, or anywhere close to it. On the other hand, it is a lot easier to remove a link if the chain turns out to be too long than to add a link.
You should rethink giving advice on a mechanical forum. Please. Whether or not you think you'll 'never go big/big' it's stupid to cut a chain too short to do it. For the OP: Forget calculators. They're not the correct way to adjust chain length. Every manufacturer has instructions for how to size a chain for their numerous derailleurs. Find those instructions. Use those instructions. You will never go wrong doing this.