Quote:
Originally Posted by trailangel
IMHO you are better off looking at gear inches than ratios.
There are not any sweet gears.

This will do gear inches but it's fairly trivial, I wanted to share something clever.
Edit  sigh  replace all smileys with colon D.
[TABLE="class: grid, width: 500"]
[TR]
[TD][/TD]
[TD]Tire size 700c x 32mm
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]rim mm
[/TD]
[TD]622
[/TD]
[TD]630 (27), 622 (700c), 559 (26 & fat)
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]tire mm
[/TD]
[TD]32
[/TD]
[TD]25 (1), 28 (1.125), 32 (1.25), 38 (1.5), 41, 45 (1.75), 51 (2), 54(2.125), 76 (3), 96.5 (3.8), 122 (4.8)
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]tire dia
[/TD]
[TD]=(B2+2*B3)/25.4
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]top
[/TD]
[TD]bottom
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]ring steps
[/TD]
[TD][/TD]
[TD]=LN(F8)/LN(D25)
[/TD]
[TD]=LN(G8)/LN(D25)
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]ratio of rings
[/TD]
[TD][/TD]
[TD]=E10/F10
[/TD]
[TD]=F10/G10
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]2step ratio
[/TD]
[TD]1step ratio
[/TD]
[TD]gear
[/TD]
[TD][/TD]
[TD]3rd
[/TD]
[TD]2nd
[/TD]
[TD]1st
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]road triple
[/TD]
[TD]52
[/TD]
[TD]39
[/TD]
[TD]30
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]8x11 to 30
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]11
[/TD]
[TD]no gear
[/TD]
[TD]=IF($D12="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D12*E$10*$B$4))
[/TD]
[TD]=IF($D12="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D12*F$10*$B$4))
[/TD]
[TD]=IF($D12="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D12*G$10*$B$4))
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]=IF(D12="no gear","",D14/D12)
[/TD]
[TD]=IF(D12="no gear","",D13/D12)
[/TD]
[TD]10
[/TD]
[TD]no gear
[/TD]
[TD]=IF($D13="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D13*E$10*$B$4))
[/TD]
[TD]=IF($D13="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D13*F$10*$B$4))
[/TD]
[TD]=IF($D13="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D13*G$10*$B$4))
[/TD]
[TD]high
[/TD]
[TD]=MAX(E11:G22)
[/TD]
[/TR]
[TR]
[TD]=IF(D13="no gear","",D15/D13)
[/TD]
[TD]=IF(D13="no gear","",D14/D13)
[/TD]
[TD]9
[/TD]
[TD]no gear
[/TD]
[TD]=IF($D14="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D14*E$10*$B$4))
[/TD]
[TD]=IF($D14="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D14*F$10*$B$4))
[/TD]
[TD]=IF($D14="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D14*G$10*$B$4))
[/TD]
[TD]low
[/TD]
[TD]=MIN(E11:G22)
[/TD]
[/TR]
[TR]
[TD]=IF(D14="no gear","",D16/D14)
[/TD]
[TD]=IF(D14="no gear","",D15/D14)
[/TD]
[TD]8
[/TD]
[TD]11
[/TD]
[TD]=IF($D15="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D15*E$10*$B$4))
[/TD]
[TD]=IF($D15="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D15*F$10*$B$4))
[/TD]
[TD]=IF($D15="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D15*G$10*$B$4))
[/TD]
[TD]overall ratio
[/TD]
[TD]=I13/I14
[/TD]
[/TR]
[TR]
[TD]=IF(D15="no gear","",D17/D15)
[/TD]
[TD]=IF(D15="no gear","",D16/D15)
[/TD]
[TD]7
[/TD]
[TD]13
[/TD]
[TD]=IF($D16="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D16*E$10*$B$4))
[/TD]
[TD]=IF($D16="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D16*F$10*$B$4))
[/TD]
[TD]=IF($D16="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D16*G$10*$B$4))
[/TD]
[TD]chain wrap
[/TD]
[TD]=MAX(E10:G10)MIN(E10:G10)+MAX(D12
22)MIN(D12
22)
[/TD]
[/TR]
[TR]
[TD]=IF(D16="no gear","",D18/D16)
[/TD]
[TD]=IF(D16="no gear","",D17/D16)
[/TD]
[TD]6
[/TD]
[TD]15
[/TD]
[TD]=IF($D17="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D17*E$10*$B$4))
[/TD]
[TD]=IF($D17="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D17*F$10*$B$4))
[/TD]
[TD]=IF($D17="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D17*G$10*$B$4))
[/TD]
[TD]RD max cog
[/TD]
[TD]=MAX(D12
22)
[/TD]
[/TR]
[TR]
[TD]=IF(D17="no gear","",D19/D17)
[/TD]
[TD]=IF(D17="no gear","",D18/D17)
[/TD]
[TD]5
[/TD]
[TD]17
[/TD]
[TD]=IF($D18="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D18*E$10*$B$4))
[/TD]
[TD]=IF($D18="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D18*F$10*$B$4))
[/TD]
[TD]=IF($D18="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D18*G$10*$B$4))
[/TD]
[TD]FD diff
[/TD]
[TD]=MAX(E10:G10)MIN(E10:G10)
[/TD]
[/TR]
[TR]
[TD]=IF(D18="no gear","",D20/D18)
[/TD]
[TD]=IF(D18="no gear","",D19/D18)
[/TD]
[TD]4
[/TD]
[TD]20
[/TD]
[TD]=IF($D19="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D19*E$10*$B$4))
[/TD]
[TD]=IF($D19="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D19*F$10*$B$4))
[/TD]
[TD]=IF($D19="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D19*G$10*$B$4))
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]=IF(D19="no gear","",D21/D19)
[/TD]
[TD]=IF(D19="no gear","",D20/D19)
[/TD]
[TD]3
[/TD]
[TD]23
[/TD]
[TD]=IF($D20="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D20*E$10*$B$4))
[/TD]
[TD]=IF($D20="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D20*F$10*$B$4))
[/TD]
[TD]=IF($D20="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D20*G$10*$B$4))
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]=IF(D20="no gear","",D22/D20)
[/TD]
[TD]=IF(D20="no gear","",D21/D20)
[/TD]
[TD]2
[/TD]
[TD]26
[/TD]
[TD]=IF($D21="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D21*E$10*$B$4))
[/TD]
[TD]=IF($D21="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D21*F$10*$B$4))
[/TD]
[TD]=IF($D21="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D21*G$10*$B$4))
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD]=IF(D21="no gear","",D22/D21)
[/TD]
[TD]1
[/TD]
[TD]30
[/TD]
[TD]=IF($D22="no gear", "no gear",IF(E$10="no gear", "no gear",1/$D22*E$10*$B$4))
[/TD]
[TD]=IF($D22="no gear", "no gear",IF(F$10="no gear", "no gear",1/$D22*F$10*$B$4))
[/TD]
[TD]=IF($D22="no gear", "no gear",IF(G$10="no gear", "no gear",1/$D22*G$10*$B$4))
[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]cog ratio
[/TD]
[TD]=D22/MIN(D12
21)
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]# gears
[/TD]
[TD]=COUNT(B13:B22)+1
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]one step
[/TD]
[TD]=(MAX(D12
22)/MIN(D12
22))^(1/(D241))
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]half step
[/TD]
[TD]=SQRT(D25)
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]1.5 step
[/TD]
[TD]=D26^3
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]2 step
[/TD]
[TD]=D25^2
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]3 step
[/TD]
[TD]=D27^2
[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[/TABLE]