Sorry, I think that I'll put on a dunce hat and sit in the corner. Do you mean that the stock RD may not work or are you just saying I may need a shorter chain?

Looks like an extremely slow link:

john@atuin:~$ wget http://cycle.shimano.co.jp/media/tec...9830799952.pdf
--2016-03-05 17:23:12-- http://cycle.shimano.co.jp/media/tec...9830799952.pdf
Resolving cycle.shimano.co.jp (cycle.shimano.co.jp)... 96.17.10.26, 96.17.10.25
Connecting to cycle.shimano.co.jp (cycle.shimano.co.jp)|96.17.10.26|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 211938 (207K) [application/pdf]
Saving to: ‘EV-FC-T551-3247A_v1_m56577569830799952.pdf’

0% [ ] 1,088 --.-K/s eta 1h 50m

The RD wrap question was only relevant to the "just replace the small ring" option several people were recommending (the rear derailleur has to be able to take up the difference between small-small and large-large; if you only change the small chainring this difference increases).

[MENTION=232894]Earl Grey[/MENTION]: Ah, thank you for the clarification! BTW, love your tea. LOL

I would just leave the gearing as it is. A difference of two and a half inches on that small of gears is absolutely imperceptible.

Ha, yes, my screen name was chosen for the tea, before I lived in the US where Earl is not an uncommon name! Was just going to say - Sheldon explains it all... Sheldon Brown's Bicycle Glossary Ca - Ce

If I understood the entry--a somewhat dubious proposition--the new crankset will work fine, thank you.