Modern Clipless Pedals
The majority of clipless pedals come in one of these variants: Shimano (SPD, SPD-SL), Look, Crank Bros,
Speedplay and TIME. Each of these systems operates with it's own pedal/cleat design that is not cross compatible
between other systems. However, with several variations, the cleat mounting hole patterns are the same between the
systems. Adapter hardware is available for most brands to move cleats between hole patterns, for example mounting a
2 hole SPD cleat onto a three hole road shoe.
These clipless pedal systems cannot be retrofitted to a shoe that does not have mounting holes, so forget about
drilling holes in your favorite pair of street shoes. Mounting a cleat requires a specially stiffened platform with
properly spaced metal threaded holes that will receive the cleats and screws.
Clipless Pedals: Hole Systems
Mounting cleats to the bike shoe will use one of three hole systems:
Two hole system: Shimano SPD, Crank Brothers, and Time MTB
Three hole system: Shimano SPD-SL, Look, Time
Four hole system: Variants of Time and Speedplay road pedals
Some shoe manufacturers have several hole patterns on one shoe. For example, a shoe may have a two and a three
hole pattern allowing mounting of either system on the shoe without using an adaptor.
Hole Three Hole and Four Hole Mounting Pattern
As you may be aware by now, the cleat is the metal or plastic piece that is attached to the bottom of your
cycling shoe. It is the cleat that snaps onto your pedal securing your feet for that full-power feeling.
Because there are different systems that fit different hole patterns, it can be confusing figuring out
what you need. I will attempt to unravel the mysteries here for you. Remember that when you buy shoes they do not
come with cleats. You will usually receive a set of cleats with the pedals you purchase. With this in mind the type
of shoe you buy will most likely be influenced by what pedal system you choose or vice-versa.
Clipless Pedal Float and Joint Considerations
As discussed elsewhere on this site, float is the amount of lateral and rotational movement a cleat gives
while clipped in to the pedal. As you sit on your bike and rotate your heel side to side, the amount of movement is
measured in degrees. Float is important as very few riders pedal without some lateral movement in their legs. This
lateral movement is the circular rotation of your foot over the pedal spindle and the side to side movement of
your heel. If you do not allow for float, your joints must compensate for any lateral movement. Within the first
few minutes of riding you will know whether you have enough float, as you will feel pain or discomfort in your
joints. Do not ride with joint pain as it will only worsen over time. Keep adjusting your setup until you are
riding pain free. Once you are aligned properly from your hips to your feet, power transfer and pedaling efficiency
will be maximized.
Types of float:
There are several different types of float—constrained and free float. Constrained float continually forces
a recentering of the foot to the neutral position due to the spring retention mechanism putting force on the
cleat. This is not always desirable as it creates joint stress while pedalling due to the spring
continually forcing the foot to the neutral position. Free float allows unrestricted movement of the
cleat within the float parameters of the pedal. The advantage of free float is
that joint stresses are minimized throughout the pedal stroke, provided the range of
lateral motion is within the float limits of the pedal.
SPD is an example of constrained float, and Time ATAC, Crankbrothers and Speedplay have free
float. A disadvantage of constrained float is that while the spring mechanism tension is adjustable, the
tension affects both float and release tension. So if you like a firm release tension the float tension forcing
your foot to neutral will also be firmer. However this tension on a free float pedal only affects how hard you need
to twist your foot to release it. The Time ATAC MTB pedal system
enables both free float and adjustable tension on the spring mechanism.
One of the best ways to determine your pedal dynamics is to have a bike fit expert watch you pedal on a trainer.
They will be able in many cases to see your pedaling dynamics and help you set up correctly. Other electronic
systems such as the Look Kéo Fit system will measure pedaling dynamics automatically.
You need to consider your pronation (foot rolls to the inside) or supination (foot rolls to the
outside) in addition to whether you walk with feet splayed out or pointed in (pigeon toed). If you take a look at
your street shoes it is pretty easy to see where the wear is. Pronation will show wear to the inside while
supination will show wear to the outside. You can buy and install shims underneath your cleats to help alleviate
excessive pronation or supination.
There are some excellent articles on bike fit over at BikeDynamics. Check them out for a great overview.
Check out these pages for a description of each of the major pedal and cleat systems:
Road Bike Clipless Pedals Cleat Systems
MTB Clipless Pedals Cleat Systems