Shimano usually pairs a 55 with a 42, so a 55/44 should be fine. Their FD specs say no more than 15tooth difference (and its good to 56T). But rubbing/dropping the chain has to do more with the adjustment (limit screws or cable tension). They may need to move the FD up a bit to clear the bigger gear but it should work fine when properly positioned and adjusted.

The 55/44 combo only has an 11 tooth jump, so the front can be adjusted without problems. Running the 44/25 should not give you a problem at all (same with the 55/12 combo). Sounds like you are getting the run around from shoddy bike store work (just my opinion).

Thanks, I thought as much.

I guess ill have to bring it to a better place and save some money!

Capacity of a front derailer is the biggest difference in chainrings that it can handle. Shimano road double is spec'd at 15 teeth but many folks (including me) exceed that by 1 or 2. You have a diff of only 11 teeth so you are not near the limit. Also, Shimano road front derailers are spec'd for a big ring of 50-56 so you are also within that spec.

Rear derailer capacity is how much chain it can wrap and Shimano short cage are spec'd at 29 teeth. Add the difference between large and small cogs on your cassette and chain rings to see how much you need. You have (55-44)+(25-12) = 24 so you are not at the limit.

Sounds to me like they messed up the adjustments when they had to move the front derailer higher to handle the bigger ring.

Chainrings are sold in matched sets, at least from Shimano and Campy. It used to be an A, B, or C, and had to do with where the ramps and pins were cut in relation to the teeth. Could be that you didn't get one that correctly matched, but...

Unless something is seriously wrong, no reason it shouldn't work. This is why I do all my own work, BTW. I don't trust a 17 year old kid to work on my bike.

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After reading the below poster, check the rings for the alignment arrow on the inside of the rings. If they are not aligned, you can have issues with the chain not going easy from big to small and vice-versa(?). Just another thing to check

this is why you should support your LBS

Most likely cause is that they had to raise the front derailleur for the new chainring, and the 17 year old kid doing the work also changed the angle of the derailleur so it is now toed out. The 17 year old kid doing the work didn't know what to do before, and he doesn't know what to look for to diagnose the problem.

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Swimming Workout of the Day:

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Find a better mechanic. My road setup is a triple and for three years I ran 55/42/30 coupled with 11-23. It didn't shift well in and out of the 30, but then I only use the 30 on days when I'm doing recovery and trying to keep zone 2 and below.

My current race setup is 56/39 RotorCrank and I've used everything from 12-27 to 11-21 (10 sp). If my front der. isn't perfect, it's possible to drop the chain on downshifts, so I've learned to "ease" it over instead of trying to hammer the shift, but it runs clean once it's shifted.

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He did use his LBS (per the OP), thats his problem, he overpaid for poor service. Which is why so many are no longer using their LBS.

Sorry to hear about your trouble, it is probably one of the examples given already. Just curious as to which crank you are using. Some of the lower end FSA Gossemers have a problem matching up to Shimano FT Der, have this type of problems.

And as far as the Blanket statements about LBS. Again not all LBS have 17 year old mechs that do not have a clue. Why do so many people have to slam the LBS industry when a few out of the 6,000 plus shops are not up to the task.

There are a lot of fabulous LBS's. But this one is clearly NOT one of those fabulous ones if they don't know how to do a simple derrailleur adjustment.

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Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

Yes, for $100 your LBS should have delivered your bike to you in 100% functional condition. I would take it back and have them give the FD another go around. That being said, an FD adjustment is one that you can do yourself. Take a look at the Park Tool website: http://www.parktool.com/repair/

They have nice pictures and step by step instructions for most basic repairs (and some not so basic ones).

I agree that 55T should be compatible with your set-up, but if you are riding a 650c bike, then the front shifting my be a bit balkier with that big chainring than with the 53T, particularly when in the smaller or larger cogs because of the more acute chain angle .