Rotor Rex 2.1 QX1 crankset review

Innovative irregular-ringed cranks

Our rating 
4.0 out of 5 star rating 4.0
GBP £269.00 RRP | USD $315.00
Rotor Rex 2.1 QX1

Our review

Light and usefully stiff with potentially power-boosting Q-Ring innovation
Buy if, You want a competitive crankset with which to give asymmetric rings a try
Pros: Light and stiff, with oval-ring facility and versatile axle system
Cons: Straight crankarms can come close to contacting chainstays, so take care with spacing
Skip to view product specifications

Rotor cranks – and the brand’s innovative non-round chainrings – are now a common site on road bikes, and they’re becoming increasingly popular off-road too.


It’s not just the Q-Rings that are unique to Rotor – the straight crankarms are triple-drilled down the centre and machined on the outside faces. Even though the 2 series’ crank arms use lower-spec 7075 alloy as opposed to the rarer 7075 mix of the 42g-lighter Rex 1 cranks, the whole setup is still an impressively low 600g.

Related: Rotor Rex 1.1 QX1 crankset

The cranks are stiff when you bounce on them or brace yourself against the bars and they’re supported on a 30mm UBB alloy axle. Rotor’s UBB system was one of the first to allow 30mm axle use across all the popular frame types too, including those normally restricted to 24mm shafts.

The reversible crank cap makes fitting and removal simple as well, so the only thing to be careful of is correct sideways spacing, as the straight arms can bring the tips very close to the chainstays on some bikes.


The arms mount onto a solid spider with multiple mount points for the unique off-centre Q-Rings, which are designed to smooth out pedalling and increase power. Rotor even offers a 30-day money back guarantee if you’re not convinced, or you can opt for a SRAM-ring-compatible spider from the start.

Product Specifications


Name Rex 2.1 QX1
Brand Rotor

Weight (kg) 0.6