Known for Q-rings, Rotor has now introduced its S1 stem using patented Double Thread Technology. This eliminates the need for a head on the stem bolts, with a double-thread pitch at each end of the stud instead.

In function, a normal-headed bolt creates stress on the tightened stem surface, whereas with DTT bolts the main threads engage the body of the stem, and the secondary threads engage the end plate.

When tightened this evenly distributes the tightening load, with the different pitches lowering the tightening force while producing a higher torque for increased rigidity. This also allows material to be taken away from the stem and bolts, lowering its weight and improving aesthetics.

Weight is an impressive 99g for a 90mm length. Rotor has also ensured that the S1 passes the EFBe Institute in Germany testing to be awarded the ?Top Performance? stamp of approval. The S1 will retail for £79.

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