abshih

Hello,

I am fairly new to road cycling and I recently got a 2013 Cannondale Super Six Tiagra and I am getting the drivetrain changed out for an Ultegra.

When purchasing the Ultegra parts, it lets me pick the Chainring sizing? How do I pick the size?

" Choose from (170mm, 172.5mm and 175mm crank arms with 34/50 chainrings, 170, 172.5 or 175 with 39/53 chain rings or 170, 172.5 or 175 with 36/52 chain rings)"

And I know my crank arm is 172.5mm based on my height and inseam, but now I need to choose between 34/50, 39/53, 36/52.

Thanks for your help