Originally Posted by
gif4445
CCCorlew, on my LHT loaded (32 lbs bike, 30 lbs pack and 205 lbs me), I used the 26-34 on many occasions touring in Western US. Yes, a heavy bike with a heavy load. The unknown will be the Roubaix on climbs such as these, with a hopefully lighter me and no pack besides the bare necessities. Changing the cassette would appear to me to be the easiest solution. Adding a third chainring would include replacing the front derailleur I assume.
I have the same bike (2011) but have a triple (50-39-30) on the front. When I rode the Triple Bypass I had a low gear of 30-28, which was fine, but I am glad that I had the low gear by the end of the day. Vail will be the easiest of the climbs on the Triple Bypass so if you used the low gear on your LHT than you probably would want to at least put a 32T cassette on the back. It's better to have a low granny that you won't use rather than to be wishing for lower gears.
It looks like the power requirement for a 6% grade at 6 mph would be about 210 W for 267 lbs and about 180 W for 217 lbs. About a 15% reduction in power requirement, but the difference between a 26-34 and 34-30 setup is huge. As someone already pointed out, much has to do with your climbing abilities but having the right setup for your abilities makes the ride much more enjoyable.
Last summer I rode the Markleeville Death Ride and beforehand I switched my 11-28 cassette out for a 12-30, giving me a 30-30 granny. This ride has some stretches of 12-14% grades so there were times I used it. I should say, though, that I prefer to spin at a pretty high cadence when climbing so if you are more of a masher, that may effect your decision also.
Hoping for warmer weather in the midwest, SOON.