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Coherent explanation coming.
Sample Gearing
Different Sprockets; Different Schemes
Schlumpf Mountain Drive
- Teeth
- 27
- 34
- 36
- 38
- 39
- 40
- 42
- 44
- 46
- 48
- 50
- 53
- 60
- High(.4)
- 10.8
- 13.6
- 14.4
- 15.2
- 15.6
- 16
- 16.8
- 17.6
- 18.4
- 19.2
- 20
- 21.2
- 24
Schlumpf Speed Drive
- Teeth
- 27
- 30
- 34
- 38
- 40
- 44
- High(1.65)
- 44.55
- 49.5
- 56.1
- 62.7
- 66
- 72.6
Schlumpf High Speed Drive
- Teeth
- 27
- 30
- 34
- 38
- 40
- 44
- High(2.5)
- 67.5
- 75
- 85
- 95
- 100
- 110
Alfine SG-S700 Gear Ratios
- Gear
- 01
- 02
- 03
- 04
- 05
- 06
- 07
- 08
- 09
- 10
- 11
- Wheel
- 0.527
- 0.681
- 0.77
- 0.878
- 0.995
- 1.134
- 1.292
- 1.462
- 1.667
- 1.888
- 2.153
Rohloff Gear Ratios
- Gear
- 01
- 02
- 03
- 04
- 05
- 06
- 07
- 08
- 09
- 10
- 11
- 12
- 13
- 14
- Wheel
- 0.279
- 0.316
- 0.36
- 0.409
- 0.464
- 0.528
- 0.6
- 0.682
- 0.774
- 0.881
- 1
- 1.135
- 1.292
- 1.467
Pinion C18 Gear Box Ratios
- Gear
- 01
- 02
- 03
- 04
- 05
- 06
- 07
- 08
- 09
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- Wheel
- 0.55
- 0.61
- 0.68
- 0.76
- 0.84
- 0.94
- 1.05
- 1.18
- 1.32
- 1.45
- 1.61
- 1.82
- 2.04
- 2.27
- 2.5
- 2.78
- 3.13
- 3.45
There shall be some discrepancies in the charts. Some have undergone SAE-to-metric conversions and back. Others have been calculated by other means. Running the same calculation repeatedly MAY return slightly variant results. PHP has trouble with division; more consistant results being sought. Gear range is the highest gear ratio divided by the lowest. Chain-wrap is the difference in slack chain between the largest and smallest gear combos; figures are listed in parentheses after the gear range.
Note the following:
- A standard 11-36 cassette has a range of 327% (25)
- The same with 11-42 cogs is 382% (31)
- The above on a DD3 or Sachs hub is 710% (31)
- An 11-46 Cassette is 418% (35)
- The above on a DD3 hub is 779% (35)
- An 11 - 52 Cassette yields 472% (40)
- The above on a DD3 hub is 873% (40)
- An Alfine 11 hub has 409% (0)
- A Rohloff 500/14 14 speed hub spans 526% (0)
- A front span of 24T to 42T yields 175% (18)
- 24T to 53T is 221% (29)
- 24T to 60T is 250% (36)
- 16T to 42T gives 263% (26)
- 16T to 53T gives 331% (37)
- 16T to 60T gives 375% (44)
- A Schlumpf Mountain Drive single disc yields 250% (0)
- With 34T to 53T it gives 390% (19)
- 34T to 60T yields 441% (26)
- A Pinion p.18 18 speed crank/gearbox spans 627% (0)
Note also: internally geared hubs are not designed for the torque delivered by extremely low gearing. Running a Schlumpf Mountain Drive voids the warranty on the Rohloff and the Alfine 11, and will pull gears out of their press-fits and strip the teeth off in the DD3.
Reckon on a safe minimum of thirty gear inches on an IGH. A late addendum: some Alfine and Rohloff bikes (prebuilt) come with lowest gears below 20 inches; as low as 18.
Last Modified: 02:14:38.65 PM America/Los_Angeles - Sat => 21st Feb 2026