The manufacturer Niner has already let the cat out of the bag and the official presentation by Sram is a simple formality: the American component specialist Sram is launching the second mountain bike drivetrain that relies on a single chainring. In terms of quality class and price (prices have only been set in euros so far), the new groupset is at X0 level.

It's not just the weight of this concept that's impressive - the omission of the front derailleur, the second or third chainring or the left-hand gearshift is just one example - bike designers are also delighted with this drivetrain. Kona, for example, had put its new Enduro on 29er bikes, which boasts unexpectedly short chainstays due to the lack of a front derailleur.

The story, or rather the key data of the X01, is quickly told: specially shaped teeth on the chainring hold the chain in place and prevent the chain from falling off in most riding situations. The cassette in turn is responsible for the gear range and offers 10-42 teeth. A special freewheel is required on the rear wheel to accommodate this cassette. In the rear derailleur, this describes a horizontal path when shifting; this process should help to ensure that the chain sits securely on the chainring.

Weights Sram X01
Crank: 665 grams incl. bottom bracket, available chainrings 30-32-34-36-38 (no 28 as with XX1)
Rear derailleur: 252 grams
Shift lever: Trigger/thumb shifter 91 grams, Grip Shift/twist grip 143 grams incl. grips
Cassette: 275 grams
Chain: 252 grams with 114 links

www.sram.com