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Schlumpf Mountain Drive and Speed Drive

We no longer offer the Schlumpf products.

We are keeping this page on the site for reference only.

Switzerland's Schlumpf Innovations makes a nifty two-speed planetary gear system that fits into the bottom bracket of your bicycle. It allows the effect of a double chainwheel derailer system without derailing the chain.

Gear shifting is accomplished without hand controls or cables. There is a button on each side of the crank set designed to be operated by the rider's foot. Push on one side for the lower gear, push on the other side for the higher gear.

There are two basic models:

Mountain Drive Provides direct drive and reduction by 1:2.5 (40%) For example, if you use a 50 tooth chainring, the low gear will be equivalent to a 20 tooth chainring!	Speed Drive Provides direct drive and increase of 1.65:1 (165%) For example, if you use a 45 tooth chainring, the high gear will be equivalent to a 74 tooth chainring!	High Speed Drive Provides direct drive and increase of 2.5:1 (250%) For example, if you use a 28 tooth chainring, the high gear will be equivalent to a 70 tooth chainring!

Schlumpf Shifting Action

Move your mouse over the images to see how shifting works.

		Optional Easy-shift lever

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