105 STI Shifters: Can I change chaingring sizes?

[xkred27]

Howdy.

I have a standard Shimano 105 group, including STI brifters and 52-42-30. As my age in years equals the number of teeth on my large chainring :eek: , I find I want a serious granny, like a 26. But since both front and rear shifters are indexed, I'm thinking that I'm locked into these specific chainring sizes. True?

I know it's not an FD capacity issue, b/c I have another ride (but with SRAM twist shifters) where the same 105 FD handles 50-38-24 just fine.

An alternative I'm also considering is a 46-36-26 touring crankset. Any hope of the 105 STI brifters working with these? Thanks. Peter.

[Peter@vecchios]

Howdy.

I have a standard Shimano 105 group, including STI brifters and 52-42-30. As my age in years equals the number of teeth on my large chainring :eek: , I find I want a serious granny, like a 26. But since both front and rear shifters are indexed, I'm thinking that I'm locked into these specific chainring sizes. True?

I know it's not an FD capacity issue, b/c I have another ride (but with SRAM twist shifters) where the same 105 FD handles 50-38-24 just fine.

An alternative I'm also considering is a 46-36-26 touring crankset. Any hope of the 105 STI brifters working with these? Thanks. Peter.

As long as the relationship to the chainrings remains about the same, no problem. With the 50/38/24 works because you lowered the FD for 50t. If it was higher for a 52/38/26(4), it may not work well but a '10s' FD, made for a 52/39/30 probably would.