If you own a pair of Shimano's RX910 or RX710 gravel shoes, the pontoons aren't optional accessories—they're required hardware that ships pre-installed and must stay on the shoe for safe pedal engagement. The SH-RX9 SPD Cleat Pontoons from Shimano are the replacement pair for when the original TPU blocks wear down from repeated pedal contact and unclipping cycles. Rather than replacing the shoes when the pontoons wear out, you swap in a fresh set and get back to a solid, stable pedal interface.

The pontoon concept is simple: two modular contact blocks mount alongside your SPD cleat, one on each side, so they follow your cleat position wherever you set it. This is different from traditional sole tread blocks, which sit in a fixed position on the outsole and only make good pedal contact when your cleats happen to be centered. By tying the contact blocks to the cleat interface itself, Shimano keeps the contact patch in the correct spot regardless of whether you've slid your cleats inboard, outboard, forward, or back.

Fitment is specific: these are designed only for the RX910 and RX710 gravel shoes. They won't work on other Shimano shoes, and the RX910 and RX710 shouldn't be ridden without them—doing so risks unintended step-outs from the pedal. Arrows on each pontoon point toward the toe of the shoe to make sure you install them in the correct orientation, and the anti-scratch paper needs to be removed before you bolt on your SPD cleats.