Originally Posted by
Drew Eckhardt
How much do you weigh, what's your mean maximal power curve look like, what's you're preferred cadence range, what happens to your fatigue when you're forced to pedal slower, and what are the lengths and grades of the climbs near you? Without that we can't provide any sort of meaningful answer.
I found that a 34x23 low gear (and 30x21 or 42x28 before that which are all the same) was enough to spin up almost any grade (obviously not the short 12% segments of Magnolia Road). A little arithmetic suggests that at 145 pounds I'd have been doing 90 RPM up 6% grades for climbs under an hour.
With a 36 small ring you need another 1-2 teeth to gain an equivalent low gear which may not be significant.
OTOH, at the small end of your cassette a 36 gives you another cog's worth of low end before you need to shift (ex - 36x13 is close to 34x12) and being able to put out over 15% more power before you shift is significant.
You have a much better idea than we do about whether or not you'll be happy with a low gear equivalent to you current 34 ring with about a tooth less.
I'm 150-155 @ 5'9. I usually hover around 8% bodyfat, lean athletic build.
I don't have easy access to a power meter, so I don't know what my power curve would be. When climbing I don't like to get under 70RPM sitting. I prefer high 80s on sustained climbs. My last big ride with 6.5k' of climbing, near the end, I was struggling with my 39/26 (legs were all cramped up).
Climbs I'll do on a regular basis are pretty short - just under 1km to ~1.5km. My favorite short hill is 0.6km, 2 sections of 20+% (garmin shows 23-25% as a max) and nothing under 10%. I'm usually fine on these climbs with my 39 ring, until I'm doing heavy repeats (10+). About once a month in the summer, I'll drive to get better climbs in, but no big mountains near by. These climbs are ~10km in length.
When I said earlier another smoother front shifting, I meant less variance in cadence.
If it matters, my bike is on DA 7900.