Up: Table of contents Fractions Improper Fractions Decimal Increments and Range
Exact drive ratios of bicycle hub gears, as improper fractions
Brand Speeds Model[1] Shifter position
-4 -3 -2 -1 (near) unity +1[2] +2[3] +3[4] +4[5]
Ratio
Bendix 2-speeds Red Band, Yellow Band         15/22 1        
Blue Band         1 22/15      
3-speeds (See Sachs, SRAM)         47/64 1 64/47      
Rohloff Speedhub, 14-speed Each value in this row is the one directly below it, times the third-stage ratio of 221/541. 3315[6] 5304[7] 34255[8]  221/541 38896[9] 6851[10] 4862[11]  
11902[12] 16771[13] 95216[14] 83855[15] 12984[16] 8115[17]
For these ratios, the third stage is locked at unity.   15/22   24/31  155/176 1 176/155 31/24 22/15  
Sachs, SRAM 2-speeds Doppel-torpedo         16/21 1        
Automatic, Duomatic, Automatix         1 64/47      
Orbit         48/65 1        
3-speeds 25,29        3/5     3/4  1        
Universal Dreigang          4/5  1 5/4      
53          3/4  1 4/3      
55          3/4  1 4/3      
All 3-speeds 1970-, 3 x 7, DualDrive         47/64 1 64/47      
4-speed Universal Torpedo        3/5     3/4  1 4/3      
5-speeds Sachs H 5100, 5113, 5120, 5213        2/3     7/9  1 9/7 3/2    
SRAM P5 5-speeds       19/30 57/73 1 73/57 30/19    
7-speeds Sachs Torpedo H 7203, -13, -20    273/460   21/31 75/92 1 92/75 31/21 460/273  
Sachs Super 7, SRAM S7, MH7205, -15, -25  252/439   21/31 72/89 1 89/72 31/21 439/252  
8-speeds SRAM G8 14/23 49/69  224/279   28/31    98/93   112/93    42/31    49/31   
  SRAM G9 112/207 14/23 49/69   224/279  28/31   98/93   112/93    42/31    49/31 
9-speed SRAM I-Motion 9[18] 161/297 4376    8/11   99/116 1 116/99 11/8 7049 297/161
  7049 4376
12-speed Sachs Elan/SRAM E12 Speeds 1   203/291 10987[19] 1 1512035[20] 3989143[21] 6529[22]  
through 6 12901[23] 1282728[24] 2993032[25] 4408[26]  
Speeds 7  258808[27] 661518[28] 1056/551 5287177[29] 13258869[30] 20835[31]  
through 12 160341[32] 374129[33] 2565456[34]  5986064[35] 8816[36]  
Shimano 3-speeds 333, SG-3S21, G-3S23, F, G, 3SC, 3CC       3/4 1 4/3      
Nexus Inter 3 pushrod shifting       11/15 1 15/11      
Nexus SG-3R75, pulley shifting       12/19  20/27 1        
4-speeds Nexus Inter 4         1 97/78 3/2 623/338  
5-speeds Nexus Inter 5       ? ? ? ? ?  
7-speeds Nexus 7-speed     12/19   20/27 3348[37] 620/627 340/297 279/209 17/11  
3971[38]
8-speeds Nexus, Alfine 8-speed   49/93 [39] 22589[40] 8134[41]  343/403 [42] 1 461/377 166/117 21/13  
35061[43] 10881[44]
11-speed Alfine 11-speed  49/93  49/72   931/1209  245/279  931/936 245/216 Ratios on the first line are 49/93 times the ones below them.
  31/24 19/13 5/3 589/312 155/72
Sturmey-Archer (Also licensees and copies: Brampton, Hercules, NK, Schwinn-Approved, Sears, Styre, SunTour for the AW, BSA for the X.) 2-speeds S2 (1966)          5/7  1        
S2, S2C, B2C (2010)         ? ?      
T,TB,TBC,TBF,TBFC,TF       3/4 1        
TC close-ratio fixed       45/52 1        
3-speeds[45] Original 1902       4/5 1 5/4      
A, C, F, FN, FX, N, S, V, X, BSA       16/21 1 21/16      
AB, AB3, AG, AT, AT3, AW, AW3, AWC, C30, K, KB, KC, KT, KTC, QS-RC3, RD-RB3, RS-RF3, RS-RR3, RX-RD3, S30, S3B, S3C, SAB3, SBR, S-RB3, S-RC3, S-RF3, SX-RB3, SX-RK3, TCW, TS-RC3, TS-RF3, XL-RD3, X-RD3     3/4 1 4/3      
AC         12/13 1 16/15      
ASC fixed        3/4     9/10 1        
AM, AM Tandem         45/52 1 52/45      
AR         69/74 1 74/69      
Brompton special BRW         30/47 1 47/30      
KS          8/9  1 9/8      
KSW          6/7  1 7/6      
S3X     5/8 3/4 1        
SW         13/18 1 18/13      
4-speeds FB, FG, FW        2/3    15/19 1 19/15      
AF, FC        3/4     9/10 1 12/11      
FM        2/3     6/7  1 9/8      
5-speeds AB5, AT5, S5, S5/1, S5/2, S5C, 5-Speed Alloy, 5 Star, Sprinter 5, XRD5, XRF5         2/3    15/19 1 19/15 3/2    
S50(W), S5C(W), S5S(W), S-RC5(W), S-RF5(W), XL-RD5(W), X-RC5(W), X-RD5(W), X-RF5(W)        5/8     3/4  1 4/3 8/5    
7-speeds AT7, S7, S7C, X-RD7, Sprinter 7[46]      3/5    20/29  115/143 1 143/115 29/20 5/3  
8-speeds X-RD8, X-RF8, X-RK8, X-RR8[47] This hub only gears up.  Gears 1 through 4: 1 41/32 29/20 120/73  
Gears 5 through 8: 1189/640 615/292 174/73 3567/1168  
S80(W), X-RD8(W), X-RF8(W), X-RK8(W)[48] This hub only gears up.  Gears 1 through 4: 1 391/300 40/27 52/31  
Gears 5 through 8: 782/405 5083/2325 2080/837 40664[49]  
12555[50]  
[1]
John Allen:
Lines in pink: need verification. Lines in blue: insufficient information or no information.
[2]
John Allen:
Unless otherwise indicated, fractions > 1 are formatted as text; Excel does not offer improper fractions as a formatting option.
[3]
John Allen:
Unless otherwise indicated, fractions > 1 are formatted as text; Excel does not offer improper fractions as a formatting option.
[4]
John Allen:
Unless otherwise indicated, fractions > 1 are formatted as text; Excel does not offer improper fractions as a formatting option.
[5]
John Allen:
Unless otherwise indicated, fractions > 1 are formatted as text; Excel does not offer improper fractions as a formatting option.
[6]
John Allen:
Numerator entered as an integer
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John Allen:
Numerator entered as an integer
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John Allen:
Numerator entered as an integer
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Numerator entered as an integer
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Numerator entered as an integer
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Numerator entered as an integer
[12]
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Denominator entered as an integer.
[13]
John Allen:
Denominator entered as an integer.
[14]
John Allen:
Denominator entered as an integer.
[15]
John Allen:
Denominator entered as an integer.
[16]
John Allen:
Denominator entered as an integer.
[17]
John Allen:
Denominator entered as an integer.
[18]
John Allen:
Reverse-engineered.
[19]
John Allen:
Numerator calculated from proper fraction
[20]
John Allen:
Numerator calculated from proper fraction
[21]
John Allen:
Numerator calculated from proper fraction
[22]
John Allen:
Numerator calculated from proper fraction
[23]
John Allen:
Denominator entered as an integer
[24]
John Allen:
Denominator entered as an integer
[25]
John Allen:
Denominator entered as an integer
[26]
John Allen:
Denominator entered as an integer
[27]
John Allen:
Numerator calculated from proper fraction
[28]
John Allen:
Numerator calculated from proper fraction
[29]
John Allen:
Numerator calculated from proper fraction
[30]
John Allen:
Numerator calculated from proper fraction
[31]
John Allen:
Numerator calculated from proper fraction
[32]
John Allen:
Denominator entered as an integer
[33]
John Allen:
Denominator entered as an integer
[34]
John Allen:
Denominator entered as an integer
[35]
John Allen:
Denominator entered as an integer
[36]
John Allen:
Denominator entered as an integer
[37]
John Allen:
Numerator entered as an integer
[38]
John Allen:
Denominator entered as an integer
[39]
John Allen:
This ratio is that of the fifth speed, times the first-stage ratio of 49/93.
[40]
John Allen:
Numerator entered as an integer. Ratio is that of the 6th speed times the first-stage ratio of 49/93.
[41]
John Allen:
Numerator entered as an integer. Ratio is that of the 7th speed times the first-stage ratios of 49/93
[42]
John Allen:
Ratio is that of the 8th speed, times the first-stage ratio of 0.527
[43]
John Allen:
Denominator entered as an integer. Ratio is that of the 6th speed times the first-stage ratio of 49/93.
[44]
John Allen:
Denominator entered as an integer. Ratio is that of the 7th speed times the first-stage ratio of 49/93.
[45]
John Allen:
[46]
John Allen:
Ratios are almost certainly correct, reverse engineered.
[47]
John Allen:
Ratios are derived from tooth counts in Sturmey-Archer technical information.
[48]
John Allen: Ratios are from tooth counts by David Moorhouse
[49]
John Allen:
Numerator entered as an integer
[50]
John Allen:
Denominator entered as an integer.