Why oval chainrings work
Oval (elliptical) chainrings work because a rider does not produce power evenly through a pedal stroke; they maximize the part of the stroke where power is produced and minimize resistance where it isn't. Oval rings make the spin cycle a lot smoother and are easier on legs while climbing. Believe it (or not), but a round chainring doesn't transfer torque to your rear wheel as smoothly as an Oval one. You will actually feel your stroke to be more "round" with an Oval shape than with a round chainring.
Why it matters
Traction, Traction and Traction. With oval rings the rear tire traction improves greatly on loose and slippery terrain. Smoother power delivery to your rear wheel means that you will be able to maintain better, constant cadence; get less stress on the joints (knees) and therefore be able to keep certain level of effort for longer. This results in higher average speed. Moreover, 11 studies made by various Universities in the World show that using oval chainrings human legs utilize more muscle groups (compared to round one), but each of them to lesser degree.
- Compatibility: Shimano Dura-Ace 9100, R9120, R9150 & R9170 Di2 and Ultegra 8000, R8020, R8050 & 8070 Di2, 105- R7000, R7020, R7070. They can also retrofit all 9000 and 6800 series cranks but use bolt covers for best appearance. 10 / 11 / 12spd compatible.
- Material: CNC machined 7075 Txxx Aluminum.
- Ovality: Optimized to each size separately. 34T- 6.5% ; 36T, 38T, 39T- 11.4%, 50/52/53T - 10-11.2% ; Timing of 108 -110.5° after TDC (top dead center) - Ideal for road climbing.
- Real weight: 117 g (48T).