Installing first shimano shifter. Have been using SRAM. Setting up on a new bike. I have shifter, RD +cable installed, but no cassette yet -- waiting for wheel. I can see the dyna sys label on the box and the shifter, but when I click through the imaginary gears, I only get 8 clicks -- like on my 9 speed. Any advice? I know this is probably my error (probably something obvious) but I'm stuck.