Is there any down side of using a mid to long cage RD on 28t and bellow cassettes?

[zmalwo]

besides the slight weight disadvantage from a longer cage and longer chain, is there any shift performance issue associated with using a mid to long cage RD with less than 28t cassette?

[Dave]

No. Remember that triple users may have a 12-25 cassette. I did for a long time. The chain won't be any longer. The big/big plus 1 inch method still works and so does the little/little method. If you're not using a triple, your small ring will be larger and a shorter chain would be the result.

[Mark McM]

As far as shifting performances, there will be little difference.

The other differences will be quite minor (at least on the road), and will include:

• More chain bounce
• The chain/derailleur cage will hang lower, increasing chance the chain/derailleur cage can get snagged on something
• The lower run of chain may be more likely to pick up dust and spray from the road
• Slightly heavier (a few grams)

As mentioned, these are really minor, and will be of no concern to most people