I will be self-supported touring down the Oregon Coast this summer. I would like to reduce my gear inches to 21, and am looking for advice on the most economical way to reach this low end gearing. Will a 26t chainring work OK with the derailer and chain? Or is this too much of jump to the 39t middle ring?
Crank Shimano Tiagra 50/39/30
Cassette SRAM PG970 11-32, 9 speed