While many people advocate the big/big method, it suggests the shortest possible chain. If you later want to change the cassette to get a larger cog, the chain will be too short. Not so, if you use the little/little method. It provides the maximum wrap capacity. If you're deliberately exceeding the RD's wrap capacity, then the big/big method must be used, but the chain will hang loose in the little ring and perhaps several of the smallest cogs, since 1 inch of chain equal 4T of wrap.


Some people here mention shortening the chain by a link or two, but the minimum increment of change to the length is two links or 1 inch of chain. You can't remove an odd number of 1/2 inch links. A link is only 1/2 inch, since they are sold as having 114 links and the length is 57 inches.