Shimano Pedaling Dynamics
Shimano Pedaling Dynamics, commonly called SPD, is a design of clipless bicycle pedals and associated cleats first released by Shimano in 1990. The first model, PD-M737, was aimed at mountain biking enthusiasts who, prior to this, had to use toe clips and straps or "road" clipless pedals which clogged with mud and made walking very difficult in unrideable situations.
Shimano makes a number of different SPD cleats, and not all cleats are compatible with all pedals, especially between "road" and "mountain" SPD product lines. Among otherwise-compatible cleats, there is an important distinction between black "single release" cleats (SM-SH51) and silver "multi release" cleats (SM-SH56). The former can only be released from the pedal by twisting the heel outwards, while the latter can also be released by a sharp pull upwards and are therefore easier to use for novices.
There is a small adjustment screw on the pedal that can be used to alter the resistance required to release the cleat from the pedal, so beginners can have it 'soft' and easy to get out, and then tighten it up as they progress.
There is a "road" version, SPD-SL, which has little in common with the type described above. SPD-SL uses a protruding plastic cleat which is attached to the shoe using the "Look" 3-bolt standard. SPD-SL pedals offer a larger contact area for long road rides, at the expense of ease of walking.
- Philip Kotler; Waldemar Pfoertsch (17 May 2010). Ingredient Branding: Making the Invisible Visible. Springer Science & Business Media. pp. 200–. ISBN 978-3-642-04214-0.
- Ed Burke (2003). High-tech Cycling. Human Kinetics. pp. 48–. ISBN 978-0-7360-4507-0.
- Tim Toyoshima (1995). Mountain Bike Emergency Repair. The Mountaineers Books. pp. 41–. ISBN 978-0-89886-422-9.