this gear calc is awesome. http://www.machars.net/bikecalc.htm

put in your wheel size, crankset and cassette, and it gives you the gear inches of all the gears, so you can see your overlap.

like, my 3x8 hybrid with 700x32 tires is running...

gear inches[TABLE="class: mytable, align: center"]
[TR]
[TD="class: c0n, align: center"][SUB]front[/SUB][SUP]rear[/SUP][/TD]
[TD="class: c1n, bgcolor: #CCFF66, align: center"]13[/TD]
[TD="class: c2n, bgcolor: #CCFF66, align: center"]14[/TD]
[TD="class: c3n, bgcolor: #CCFF66, align: center"]15[/TD]
[TD="class: c4n, bgcolor: #CCFF66, align: center"]17[/TD]
[TD="class: c5n, bgcolor: #CCFF66, align: center"]19[/TD]
[TD="class: c6n, bgcolor: #CCFF66, align: center"]21[/TD]
[TD="class: c7n, bgcolor: #CCFF66, align: center"]23[/TD]
[TD="class: c8n, bgcolor: #CCFF66, align: center"]26[/TD]
[/TR]
[TR]
[TD="class: c0n, bgcolor: #CCFF66, align: center"]48[/TD]
[TD="class: c1n, align: center"]99.8[/TD]
[TD="class: c2n, align: center"]92.6[/TD]
[TD="class: c3n, align: center"]86.5[/TD]
[TD="class: c4n, align: center"]76.3[/TD]
[TD="class: c5n, align: center"]68.3[/TD]
[TD="class: c6n, align: center"]61.8[/TD]
[TD="class: c7n, align: center"]56.4[/TD]
[TD="class: c8n, align: center"]49.9[/TD]
[/TR]
[TR]
[TD="class: c0n, bgcolor: #CCFF66, align: center"]38[/TD]
[TD="class: c1n, align: center"]79.0[/TD]
[TD="class: c2n, align: center"]73.3[/TD]
[TD="class: c3n, align: center"]68.4[/TD]
[TD="class: c4n, align: center"]60.4[/TD]
[TD="class: c5n, align: center"]54.0[/TD]
[TD="class: c6n, align: center"]48.9[/TD]
[TD="class: c7n, align: center"]44.6[/TD]
[TD="class: c8n, align: center"]39.5[/TD]
[/TR]
[TR]
[TD="class: c0n, bgcolor: #CCFF66, align: center"]28[/TD]
[TD="class: c1n, align: center"]58.2[/TD]
[TD="class: c2n, align: center"]54.0[/TD]
[TD="class: c3n, align: center"]50.4[/TD]
[TD="class: c4n, align: center"]44.5[/TD]
[TD="class: c5n, align: center"]39.8[/TD]
[TD="class: c6n, align: center"]36.0[/TD]
[TD="class: c7n, align: center"]32.9[/TD]
[TD="class: c8n, align: center"]29.1[/TD]
[/TR]
[/TABLE]


so... if I'm in my granny ring (28), I just use the bigger 4-5 max in the back, then go to the middle ring... by the time I get up to middle + 14, I'll step over to big+17. I generally use the big ring with 21-13, right now my strength is such that I'm cruising the flats in the 68-92 gear inch range, mostly around 86 GI.

my bike came with a stupid 11-34 rear, which I found ridiculous. if I can't push 30 GI up a hill, I should get off and walk (haven't yet).