Chainring range on Tiagra FD-4503
 

Hello all, I own a 2011 Masi Randonneur and would like to have a little lower gearing for loaded touring. I've been searching around here for info, but haven't found an answer to this specific question.

Background: I swapped out the RD (now a Deore Mtn Bike RD) and cassette to get from 11-25 to 11-34 teeth. That has helped, but I would like a smaller ring up front too.

Right now the front triple (Tiagra FD-4503) has 50/39/30 rings on it. The Shimano manual says this derailleur should have a front tooth difference of 20 teeth or less. But, I'd like to get away with only buying one (smaller) ring, probably a 26t.

Does anyone know if the FD-4503 would work with 50/39/26 (24 tooth difference)?

Thanks for your help!

I can't answer your specific question but I can say that I am running that FD with 50/39/28 chainrings. I pair that with an 11-34 cassette for loaded touring (e.g. pulling a trailer with camp gear, food, etc. for two people through the Canadian Rockies).

Thanks Ryker, it sounds like the 20t range is more of a strong suggestion than hard-fast rule. Do you have any problems shifting on the FD with that setup?

Sorry - should have said in my original reply. Shifts flawlessly. FWIW I used a granny ring from Sugino. My ring is asymmetric so the gap between chainrings is only correct if it installed in the correct orientation.

I currently using a Tiagra on a 46/36/20 crankset. I've also used it on a 48/36/22 and a 50/39/24. No issues.

The 50/39/24 had some problems with the chain being able to sneak in behind the 39 and jam but that's not a derailer issue. There's a lot of open space between the 39 and 24.

Thanks for the help guys. When I have the funds I'll put that 26 on there.

Do it. I've swapped out the factory 30T chainring for a 26T on a bunch of Shimano and even a Campy triple road cranks with great results. They are all geared 52/42/26 or 53/42/26 and shifting is fine. They are all a bit sluggish upshifting from the 26 to the 42 but they do shift and you aren't in a big hurry for that shift anyway.

why dont you just try a 12-36 cassette, that way you dont have to mess with your chainrings.

I'm using that FD with a 52-42-26 triple without any issue, and it shifts fast, and clean.

A 26 tooth should work fine. I would recommend also installing a Chain Catcher or some other chain retention device to prevent derailments when shifting into the small ring. Using a smaller chainring is generally preferable to using a bigger-range cassette because it keeps the spacing between the cogs a little better, and it is also a lighter setup.