To fit the cleats, you’ll need to make sure your cycling shoes are compatible with the two-bolt SPD cleats preferred for mountain bike shoes and urban riding, not the three-bolt cleats used on road cycling shoes.
There’s an arrow at the front of each cleat to make sure you attach them to your shoes the right way round. They’re interchangeable between left and right shoes.
The only clue as to which type of cleat you have is the SH51 cleats are black, whereas the SH56 cleats are silver-coloured, plus there’s an M embossed on the rear-facing tab of the SH56.
On the other hand, most riders find it relatively easy to get used to single-release SH51 cleats and the twisting-out action necessary to disengage. The learning curve is a lot less steep than with the road-going SPD-SL pedal system.
If you’re riding on more technical terrain, particularly off-road, having multiple release angles may be a disadvantage, because you’re much more likely to come unclipped when you don’t want to. That’s why Shimano’s off-road pedal range comes with SH51 cleats rather than SH56.
When comparing Shimano SPD SH51 and SH56 cleats, the main distinction lies in their release mechanisms. The SPD SH51 cleats offer a single-release direction, allowing riders to disengage from the pedals by twisting their heels outward. This design provides a secure and reliable connection, making them a popular choice for off-road cycling and mountain biking.
On the other hand, the SPD SH56 cleats feature a multi-release design, enabling riders to disengage from the pedals by twisting their heels outward or pulling their feet directly upward. This versatility makes them well-suited for riders who may encounter challenging situations or prefer a quick and easy release, such as commuters and recreational cyclists.