One (expensive) option for wide-range gears on a compact double....

I'm now upgrading my CX bike's SRAM 50-34 compact double with a XX RD and XX 11-36 cassette (11-12-14-16-18-21-24-28-32-36). I'll have a 122 inch high gear with the 50-11 and a 25 inch low gear with the 34-36. Not everyone needs such a low gear, but I'm planning on taking the bike on some trips where I'll be in the second or third of 90+ mile days in the western mountains and I want the safety net of having a bailout gear, especially with my bad knees.

The drawbacks (obviously) are the big jumps in the rear cogs (14%-17% typically), but this can be somewhat mitigated by finding an in-between gear on the other ring. Even with double-shifting, there is one "worst case" jump of about a 14% change in gearing right in the 14-15 mph cruising gears which may be bothersome on long gradual uphills, but such is the compromises one makes. If I had my druthers, I'd make the smallest cog on the back a 13 and tighten up the spacing to avoid the three-tooth jump from 18-21.

- Mark