Originally Posted by msheron
What rear cassette would give best climbing gear options...........a 12-23, 12-25, 12-27, 11-21, you get the picture.
If best = lowest then obviously the 12-27.
If best = most low gear choices when climbing hills....then I still think it's the 12-27, especially with the 10-speed where the lower gears are "filled in" a little better than on my 9-speed 12-27.
Or some crazy custom cassette with a 29 or 31 tooth cog with a mountain derailleur...but my guess is that's not the route you need to go.