Heres my little dilemma. Im a new builder and regarding the chain I have it loose on small to small, and just nicely right on Large to large
Or less a link,
Tight on Large to large and just right on small to small this almost maxes the pull and extension of my rear der in Low gear.
Im a flat and hilly roader..but more flat than hilly. Im thinking that for climbing situations I dont want to overstress my drivetrain springs/chain.. so I may keep it the first situation.
As long as large/large and small/small don't throw up any large problems, like bending the rear derailleur or making the chain jump, the setup is probably fine. You shouldn't be using those combinations, they're bad for the drivetrain - they wear stuff out and they're inefficient. You don't even need those ratios, e.g. large/large on a (typical) 53/39 and 12-25 setup is pretty much the same gear ratio as 39 at the front and 19 at the rear, and that one will have a much better chainline.
Sounds like your ok. The general guideline (per Shimano) is: if you have a double, the pulley cage should form a 90 degree angle to the ground when in the large ring/small cog combo. With a triple, the setup (even though 2 or 3 gears are unusable) is the chain shouldn’t rub together when in the small ring/small cog combo. If it does remove a link or two. I have a triple, and I’m optimized for both. Parktool.com and sheldonbrown.com offer other chain-sizing methods.
Ahh thanks alot guys. I had read about not using the outergear ranges as you suggested so Im maintaining the present fit. ITs my first STI system and I just ran it out a few miles...quite a godsend to shifting. I like that 90 degree guidline as well thanks,
Originally posted by p55mac ..........if you have a double, the pulley cage should form a 90 degree angle to the ground when in the large ring/small cog combo.....
More precisely, the imaginary line that intersects both pulley centers should form a 90 degree angle to the ground.
