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:

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.

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