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The simplest, cheapest, quickest thing you can do is to put a smaller ring on the front. It is not clear what you have on there currently so cant recommend specific. Shimano ultegra road triple front deraileurs of that era were very finicky about tooth difference but I think that is mostly big to middle, not so much middle to small so you should be okay with 26 or 28. The downside is the big jump from middle to small.
Anything other solution will require more parts-cassette, rear deraileur, cranks, chain. Putting a 30 on the rear is about a half gear so you want more than that unless combined with change in the front. Anything beyond that will probably require a different rd such as suggested above because Shimano road long cage rd were designed for chain rap rather than sprocket capacity.
Agree that the best solution is to replace the entire drivetrain and get a 46/30 or 44/30 compact crank with 34 or 36 cassette. And yes you will have to replace the front rd as well as the rear because now you will run up against the finicky min and max tooth difference limits on the ultegra triple front. It was designed for 10Tdifference and you can barely get away with 9-12, or maybe 13 if you are lucky. I actually have this front der on a tandem*, though it might be the 6700, with a 13T difference and have gotten it to work-barely- with some careful hand bending/messaging. The Dura Ace triple front actually has a wider range and can do 14T no probs.
*Edit: I checked and it is 6700 and actually 50/39 so 11T difference that is just barely working, and in fact was rubbing yesterday. So I may be at the low end of the spec for tooth difference on this model deraileur. Point being that these are sensitive tooth difference.
Last edited by marciero; 07-04-2022 at 10:11 AM.
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07-02-2022, 05:49 AM
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