TRiPEAK AOPW puts a larger pulley into a compatible original derailleur cage. Its asymmetric mounting design gives the chain a gentler path while keeping the upgrade compact.
Why an 18-tooth pulley?
Each chain link changes angle as it travels around a pulley. A larger pulley spreads that turn over more teeth, reducing the bend at each link. In its 18T versus 11T explanation, TRiPEAK identifies reduced chain deflection as the reason for the larger lower pulley. That is the mechanical benefit the design is intended to deliver.
The asymmetric mount keeps the original cage
AOPW is short for Asymmetric Oversize Pulley Wheel. The mounting point is offset within the wheel, allowing a larger pulley to sit in the supported stock derailleur arm. The official technology page also describes a hollow frame that makes room for a larger bearing and supports the oversized wheel.
Does it need a longer chain?
TRiPEAK says the compatible AOPW upgrade retains the stock cage and does not require a longer chain. Its installation overview explains that the asymmetric design keeps the chain path within the intended original trajectory. The same article asks installers to check that the existing chain length is appropriate for the bike’s setup.
How the pulley body is built
TRiPEAK describes molding the composite pulley around its bearing, instead of pressing a bearing into a finished wheel. Its construction article links that close fit to bearing alignment and describes quieter running and wear resistance as benefits of the composite body.
Choose the kit for your derailleur
| Your setup | What to match |
|---|---|
| Shimano road | Full derailleur code, such as R8100 or R9200, plus the kit’s tooth combination. |
| Shimano GRX | The exact RX model and whether the drivetrain is 1x or 2x. |
| SRAM | The listed Road AXS generation, XPLR, Eagle or T-Type application. |
| AERO or EVO | The model-specific fit and listed tooth count; these listings include both 12/16T and 12/18T options. |
Compare TRiPEAK AOPW kits by the full derailleur model. If you want replacement wheels for the existing setup, see the separate pulley wheel sets. Open the matching official installation manual before fitting either type.