WHEELTOP EDS OSPW Carbon Cage Upgrade: Installation and Ride Review

I just unboxed and installed the new WHEELTOP oversized pulley wheel (OSPW) system for my EDS TX rear derailleur, and I have some great insights to share. Unboxing it reveals a beautiful piece of kit with nice foam cushioning. I chose the 3D holographic rainbow option, which features a gorgeous carbon cage. Spinning the pulleys side-by-side, the smaller ceramic wheel spins seemingly forever, while the larger one has a bit more resistance out of the box, but the larger bearing size inherently means less mechanical drag and fewer link-bending friction losses when the chain is fully loaded. By allowing each chain link to bend less around a larger diameter, this upgrade saves energy and marginal wattages over long distances.

The installation is surprisingly straightforward. Using a 3mm Allen key, I removed the tiny stop screw on the stock derailleur, allowing the cage to unwind and lose tension. Next, a 2.5mm Allen key takes off the retaining bolt holding the stock cage to the main body. For a quick weight comparison: the stock setup weighs 75 grams, while the new OSPW system comes in at 106 grams. So yes, you are gaining a bit of weight for the sake of mechanical efficiency and looks. Putting it back together, I fitted the spring into its designated slot on the new carbon cage, aligned it, and tightened the 2.5mm bolt. To tension it, I had a small clearance issue where the cage hit the battery area, so I used my shifter to shift up into an easier gear to clear it, wound the cage backward, and reinstalled the 3mm stop bolt.

When putting the chain back on, I noticed WHEELTOP included a fantastic built-in retaining tab on the cage that prevents the chain from slipping off the pulley—something cleaner-looking cages on the market omit, causing headaches for riders. I’m running a wild, custom 13-speed setup with a 10-36t cassette plus a 40t extender. Surprisingly, I could shift into the largest cog without changing my chain, but it was a massive stretch, so I ended up adding about four links to safe-proof the drivetrain.

After taking it out for a rough gravel test ride over some brutal washboard roads, the system performed flawlessly. The chain stayed perfectly seated with zero clanking or skipping, and the ride was remarkably quiet. However, I did encounter one minor setup quirk: out of the box, the derailleur wouldn't drop into the smallest cog, meaning this upper pulley sits slightly more inboard compared to the stock version. The big mistake to avoid here is manually adjusting every single individual gear on your app. Don't do that! Instead, just go into your initial calibration settings, make three or four micro-adjustment clicks outboard to realign the baseline, and the app will perfectly maintain the spacing across the rest of the gears. Overall, it’s an incredibly simple and functional upgrade that makes the bike look race-ready. Even if the wattage savings act as a subtle placebo in the back of your head, the stunning aesthetic alone will definitely make you want to ride your bike more.