Originally Posted by
sstorkel
Yes. But check to see what your front derailleur can handle. Specs for most say max of 16T difference between two adjacent chainrings and max of 22T difference between smallest and largest. That's why when you drop to a 26-tooth small ring you also have to drop the large ring to 26+22=48T. You might be able to get away with larger jumps, but shifting quality sometimes suffers if you go that route...
I don't have experience with road front derailleurs, but with the few mountain bike FDs, their quoted capacity is much smaller than their actual capacity (On my folding bike, for example, I have an SRAM X.9 triple FD that I use to shift 50/39/24 crankset which is well beyond it's capacity but works beautifully).
That being said, you're absolutely right to point out that this needs to be a consideration as some FDs clearly won't work.
Originally Posted by
jim p
If cost was no object, I would take the bike out and ride it as slow as I could without falling over. Then I would set the gearing so that at my fall over speed my cadence would be 90 rpm. Since I don't care to go over 30 mph, I would set my top gear so that I would be doing 30 mph at 90 rpm cadence.
I think this isn't a crazy way to go about it.
For
my folding bike gearing, I'm actually pretty close to this (4.7 mph to 28.3 mph at 90 RPM) although I'd like to go both a little lower and a little higher.