Originally Posted by
justinzane
28F/28R ~= 1
...
48F/11R ~= 14
That is with a 28/38/48 triple front and 11-28 rear. Gear numbers are based on a cadence-equivalence spacing.
Unless question was misunderstood (lowest gear actually USED, not lowest gear available); If 28F/28R is actually the lowest gear you use on your rides, even a 34F 32R would not cover that range.
Find the lowest gear that you actually USE to comfortably get over hills on your rides. Then use the sheldon tables to find gain ratios equivalents and figure out what combination in stock compact cranks / cassettes would cover those ratios. Add an extra low cassette sprocket for good measure and you'll be set.
Say you actually use 28F/25R to get over the hardest climb. 28F/25R is almost the same as 34F/30R or 36F/ 32R. Stock road cassettes do not go over 32 (and you'll need a long cage rear derrailleur for 32). So for good measure i'd go with 34F/32R (34F/30R would cover your current lowest gear need, having the 32R would be there for saving the bad days, longer rides, longer climbs, hill repeats, etc).