11-28 to 12-30 - Will I need a new longer chain?
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You may need a longer chain, however....do you have the new low range Ultegra mech? They brought out new low range 105 and Ultegra mechs to cope with the larger 30t. Your older one may not work. The new ones have a longer cage, and a slightly larger parallelogram.0
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ah. I've had my 6700 for over a year now so I'm guessing not. Though I seem to remember vaguely something about using 30T cassettes (before Shimano released them) working ok even though 28T was the largest listed as compatible... Perhaps someone will pop in and clarify the situation.0
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Sometimes they can 'work' but not always as they should. You could get away with it, but don't be too shocked if it doesn't and you have to fork out for a new RD as well.
Shimano's new low range RD's go up to 32t on the rear.0 -
Thanks for the info. I'll give up on the idea.. 28 should be enough anyway!0
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I'm no mechanic but if you put your gear onto the 28T sprocket and there is plenty of room between it and your RD then I guess a 30T would fit? As for a longer chain I doubt it as long as you don't use Big front and 30T rear.0
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Hi there
Been quite a few threads on this topic in the past including one I started myself back in April last year
viewtopic.php?f=40004&t=12850935&hilit=12+30
I had no problem with the switch and if IRRC - most of the others who posted on the topic were equally successful.
Most negative comment is based on theoretical chain/sprocket/ rear mech capacity calculations or limits advised by Shimano themselves. Those who have actually done the switch have generally had no issues barring maybe a tweak to the indexing or B-screw adjustment.
My advice would be to give it a go. After all the Tiagra 12-30 cassette is only about £20 and if you do have problems then it's not the end of the world to buy and fit a new chain0
