campy cassette cog-9 speed
Currently I have a 53/39 up front. In the back I have 12,13,14,15,16,17,19,21,23.
Going on a ride in late August that has a lot of climbs. I don't think the 23 in the rear is going to cut it for my granny gear. I need another climbing gear.
What would be suggestions on what do go with? 25,26,27 or 28? I can do steep climbs in the 23 but can't sit. I need a sitting gear. Looking at doing 15,000 ft of climbing in 3 days and 200 miles. Those climbs could be rough near the end. Legs might be shot.
Is it possible to then pull the 12 and insert the new cog? Or do I replace one of the other gears?
This is what I'm looking at buying. Can order in any of the sizes. Will one of these work?