Schlumpf Mountain Drive 130mm BCD 170mm Crankarms


Regular price $825.00 Save $0.00

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Schlumpf Mountain Drive 130mm BCD 170mm Crankarms

The ingenious Schulmpf cranksets utilize a heel-activated, two speed planetary gearing system in the bottom bracket and spider to achieve a high and low range without multiple chainrings, front derailleur or shifter. Schlumpf cranksets are available as a Mountain Drive, Speed Drive, or High Speed Drive. The Mountain Drive uses a direct drive 1:1 ratio, and a low gear 2.5:1 ratio. The Speed Drive uses a direct drive 1:1 ratio, and an overdrive 1:1.65 ratio. The High Speed Drive has an integrated 27T ring with a 1:1 ratio and a 1:2.5 overdrive. All fit standard 68mm bottom bracket shells and are suitable for tandems. The efficiency of the planetary gears is 95 - 97%. The bottom bracket has to be chamfered at 45° on both sides. Stocked with aluminum cones for steel bottom bracket shells. The Torque Arm Mountain Drive will only work with single or double chainrings but it eliminates the need to chamfer the bottom bracket. Includes bottom bracket and spider, crankarms (170mm), crankarm bolts and shift buttons. Chainrings not included.
Your bike's bottom bracket shell must be chamfered 45° on both sides for non-torque arm applications - chamfering will not affect normal bottom bracket installation in the future. Please call for chamfering options.
-Mounting a non-torque arm Schlumpf in an aluminum bottom bracket shell requires a serrated steel cone - available separately.
-Larger chainrings for High Speed Drive. Schlumpf now has an adapter available that allows the use of steel chainrings of 30t and 34t to be used with the High Speed Drive. The same adapter facilitates mounting a spider with BCD 130mm, which is good for chainrings of 38t or larger.