What Is the Shimano SM-SH51 SPD Cleat and When Do You Need It Without the Cleat Nut?

The SM-SH51 is Shimano's standard single-release SPD cleat, designed for all Shimano SPD two-bolt clipless pedals used across mountain biking, commuting, touring, and gravel applications. Single-release means the cleat disengages with a specific outward heel twist, providing a more secure and predictable connection to the pedal than multi-release cleats during aggressive cornering, steep climbing, or sprinting where accidental unclipping would be a problem. The cleats are made from heat-treated forged steel for long-term wear resistance under repeated engagement and release cycles, which matters for riders clipping in and out constantly in technical terrain or urban stop-and-go conditions. This version is sold without cleat nuts, making it the correct choice for shoes that have built-in threaded inserts in their cleat mount platform, which covers most modern SPD-compatible cycling shoes.

The SM-SH51 provides 4 degrees of float, allowing the foot to rotate slightly within the cleat engagement before releasing, which accommodates natural variations in pedaling biomechanics and reduces knee stress compared to a fully locked zero-float cleat. Cleat position is adjustable within the shoe's slot for fore-aft placement and rotational angle. Each set includes two cleats and bolts. If your shoes require separate cleat nuts rather than threading directly into the shoe body, choose the version sold with cleat nuts instead. For riders on Shimano SPD pedals who want reliable single-direction release with forged steel durability and 4 degrees of float, the SM-SH51 without cleat nut is the standard go-to SPD cleat.