Understanding Shimano SPD Pedals and Cleat Technology
When Shimano rolled out the SPD system in 1987, it was the first clipless pedal and shoe system designed for off-road riding. Mountain bikers at the time had been experimenting with clipless pedals and shoes designed for road bikes, seeking a better connection to their bikes and more efficient pedaling performance.
This solution was far from ideal, however, since those designs didn't meet the needs of mountain bikers. The one-sided road pedals were difficult to clip into and challenging to get out of on tricky terrain. The shoes had hard, stiff soles with massive cleats and little, if any, tread. This made the road setup unsuitable for taking even a few steps off the bike, let alone to navigate rocky hike-a-bikes, muddy sections, or stream crossings.
Shimano's SPD system solved all of these problems with a reliable and straightforward design that delivered on everything mountain bikers needed back then, and what they still depend on today. SPD cleats and pedals offer ease of entry and exit, good mud-shedding ability, a stable and efficient pedaling platform, and a comfortable, secure connection to the rest of the bike.
With the introduction of SPD, all of a sudden, mountain bikers were able to realize the power delivery that road riders enjoyed and that connection to the bike provided extra stability in rough sections of trail. Plus, the SPD system provided the ability to walk normally when off the bike, thanks to the recessed cleat design.
In a testament to how good that original SPD design was, it has not changed since 1987. SPD pedals have seen many refinements over the years, but the cleat design and interface are the same now as they were back then and are still considered the standard against which all other clipless pedals are judged. In an industry that has seen so many changes since the early days, it is remarkable that the original SPD design has stood that test of time.
One of the keys to SPD’s success is how easy they are to use. To clip in, simply place the cleat above the cage on the pedal and step down firmly. A slight forward motion while stepping down is the key to quick entry. The cage will grab the cleat at the front and the back, holding it firmly (with some float built in to allow your joints to move naturally as you pedal). Exiting is even easier: kick your heel out, and the spring's tension will release, allowing the cleat to come free from the cage.
Riders who clip in will appreciate the connected feeling between feet and pedals, but some like to feel more secure than others. One of the defining features of SPD pedals since the beginning has been the ability to adjust the pedals' spring tension according to personal preference. Racers and riders seeking performance and a secure connection under heavy output tend to favor a stiffer spring tension, which also requires a more positive motion to exit the pedal. Others may prefer lower tension if conditions are less demanding or if they ride in terrain where a fast exit may be necessary.
Whatever your preference, setting the spring tension to suit your needs is quick and easy. Simply use your 3 mm Allen key to increase spring tension with clockwise turns or loosen tension by turning the bolt counterclockwise. Don’t forget to adjust both springs on each pedal if it is a double-sided SPD design!
SPD cleats are quite durable, but as they wear, performance can be compromised. Usually, this will mean inconsistent releases: your pedal may release with more or less effort than when they were fresh, or in some cases, they may not release properly. A good rule of thumb is to replace your cleats once a year. For more on changing cleats, see this tune-up guide.