Shimano's SPD bike pedals have become the industry's standard mountain bike pedals. Their no-frills design, excellent reliability and ease of set-up and maintenance make for a comfortable and worry-free ride no matter what terrain you ride on. When first beginning to ride with clipless pedals however, it can be rather disconcerting to try to detach yourself from the bicycle when coming to a stop. Luckily, SPD pedals can be adjusted to make exiting the clips as easy and painless as you need, making learning to ride with clipless pedals a smooth experience.
Set one foot in your SPD pedals. Twist your foot to the outside of the bike to unclip. Repeat this a few times to get a feeling for how you want to adjust the pedals--whether they need to be easier or harder to unclip from.
Set your bike on its kickstand, in a dedicated work stand or on a stationary trainer so that you can work without worrying that the bike will fall over.
Locate the float adjustment bolt at the rear of the pedal. Above the adjuster bolt are two markers, a "-" and a "+" symbol. Twisting the bolt counterclockwise toward the "-" makes the pedals looser, allowing for an easier dismount. Twisting the bolt clockwise toward the "+" makes the pedal tighter, and therefore more difficult to exit.
Determine which direction to turn the bolt and do so using a 2mm hex wrench. Set your foot in the clips once more and clip out. Notice that the difficulty of exiting the pedal has changed since you twisted the adjuster bolt. Repeat this motion a few times. If you like the new setting then you're ready to ride--if not, you can make further adjustments by twisting the adjuster bolt further in either direction.