Originally posted by ed gavin
Question 2, which wasn't so clear refers to the different sizes I see for cranksets (or chainwheel?), some have numbers like 52/42/30 compared to 42/34/24.
I guess I'm asking if you have more gears and a smaller crankset is that any better or worse than having less gears and a larger crankset? Or should you always try to get the most gears and the largest cranksets?
The right gearing is that which best matches the specific rider to the type of riding s/he's doing.
Keep in mind that you should avoid cross-chaining (using an inside chainring with an outside cog, or vice-versa). Therefore you can see that by basic design, the biggest chainrings are intended to combine mostly with the smaller cogs, and vice-versa.
Using the calculator at
http://www.sheldonbrown.com/gears/ you can see that on a bike with a 52-42-30 crankset and an 12-25 cassette, a pedaling cadence of 80 would give you a speed range of 7.5 to 27.1 mph. Appropriate for a road bike. Less appropriate for a touring bike. Not at all appropriate for a mountain bike.
Do the same calculation with a 42-32-22 and a 12-34 cassette, and you get a speed range of 4 - 21.6mph. This bike would be able to climb almost anything, although it would spin out on the road for many riders.
IMO, most road and touring bikes today are geared too high; only road racers and those who ride like one need or can really use a 52-11, whereas almost everyone sometimes wishes for lower gears than what they have.
Many of today's hybrids come with what I feel is close to perfect gearing for a multi-purpose 700c bike: 48-36-28 in front, 11-32 in back. 12-34 would be even better.
RichC