AeroCoach ARC DUAL TT carbon chainrings £235.00 incl. tax* Size 54/40 58/44 60/44 62/46 BCD 130 130 hidden bolt Custom - 110bcd 4 bolt Custom - 110bcd 5 bolt Custom - 110bcd 5 bolt - hidden bolt Power meter cutout No Yes - enter details in order comments Add to basket View basket PLEASE NOTE - current lead time for ARC DUAL chainrings is four weeks from order dateAeroCoach ARC DUAL chainrings adapt with you as you ride. The subtle noncircular shape changes from inner to outer ring, to match your muscular activation during low and high inertia riding. Full carbon for lower frictionSolid aero designLarger sizes for improved drivetrain efficiencyBiomechanically optimisedSuper stiffSlick shifting using four lifting pins and custom rampsHard wearing with reinforced outer ring thickness BIOMECHANICS ARC DUAL TT chainrings have subtle shapes designed to mimic the firing patterns of your leg muscles whilst riding, increasing the gearing size when you most need it. The inner and outer ring differ in shape to account for varying inertia as you ride:The ARC increases gearing quickly at the beginning of the pedal stroke as this is when the main force producers activate (gluteus maximus, vastus medialis & lateralis, as well as the tibialis anterior). After this period gearing is maintained all the way through the highest torque phase before gradually decreasing down to a minimum gearing at bottom dead centre. This smooth dropoff is when the effect of gravity and the lower leg muscles come into play.The unique noncircular design will help increase power output by 3-5w, and allow a smoother pedal stroke than normal in all situations. Unlike other noncircular designs you can train on the ARC ring without causing a detriment to your pedal stroke and swap between round/ARC rings without difficulty. In addition, there will be little to no power inflation (<1%) when using the ARC on a crank/pedal based power meter.SMOOTH SHIFTINGARC DUAL chainrings have 4 lifting pins on the outer ring, enabling smooth easy shifts. As with all chainring types shifting front rings under heavy load is not recommended and will affect shifting performance.Cross chaining in the inner ring (using small sprockets at the back of the cassette along whilst in the inner ring) is bad for the chain, bad for efficiency and will result in poor performance. Using an ARC DUAL inner ring in combination with the 4 smallest sprockets on the cassette is not recommended.ROBUSTNESSARC DUAL chainrings are hard wearing with a reinforced outer chainring and will last for 12,000km+ if your drivetrain is kept clean. Harsh weather riding will cause excessive wear on your drivetrain and so extra care should be taken to keep your bike and chain as clean as possible if you ride in inclement weather.Please ensure that the chainring is protected at all times when not riding the bike, and that framesets with no wheels on are not rested with the chainring touching the ground.CUSTOM BCDWe can manufacture carbon ARC rings for any BCD to fit your exact crankset: if you need a chainring with a non 130BCD fitment, then please select your option from the drop down list above. If you choose a custom BCD option please allow at least 3 weeks for delivery as we build the rings to your specification.INSTALLATIONInstall your ARC DUAL chainring as normal, placing the small white marker on the reverse of the chainrings inline with the crankarm, and ensuring that the front mech height is set for when the teeth are at their highest point on the outer ring. Incorrect installation and damage of an ARC DUAL chainring is not covered by warranty.ARC rings in larger sizes (60 & 62t) may cause fitment issues with your frame and or front mech. Please allow for 260mm chainring diameter when measuring your frame and front mech height for fitment. * Based on residence in United Kingdom. Tax rates for other countries will be calculated at the checkout. Price exclusive of tax: £195.83.