Pedals are one of three contact points with the bike. The other two, saddle and handlebars, are primarily comfort-oriented and help you stay planted in the optimal position - assuming you've found it - hour after hour. Pedalstroke efficiency is arrived at through good bike fitting, and good pedaling technique through an understanding of form and application of natural biomechanical patterns.
So what do the pedals do for us?
Didn't we all essentially pedal on rubber blocks as kids? Didn't that kid next door just ride on the pedal axle, after the platform broke off? Are we overthinking pedals? Do they get too much, or too little, credit?
Pedals are our way of pushing the crankarm (or in simplest physics terms - the lever) around its axis in the bottom bracket. The height of the pedal platform above its axle determines how far away we are from that lever arm itself, opening up a gap through which we may lose power, so manufacturers are often trying to minimize that distance. On the pedal's underside the aim is to minimize the chance that the pedal hangs so low that it scrapes the ground in a sharp turn. In other words, there are features to the design that make pedaling relatively free of obstructions.
Human vs. Robot
The biomechanical aspect of pedals is that they are the interface between a rigid machine (the bike) and an evolved organism (us!). While many of us aim to become "one with the bike" as we ride, it is vital to recognize that we evolved to do something much different than pedal perfectly planar circles. Instead, we evolved complex joints that allow us to walk and run efficiently on two legs over highly varied terrain (interesting link about gait). Compared to other mechanically-assisted endurance sports, such as speed skating and skate skiing, cycling has a very narrow range of motion. Too often in cycling and bike fitting, eliminating the ability of our complex joints to move freely, or requiring them to imitate the pistons of a rigid machine, leads to discomfort and injury. At Fitworks, translating natural movement patterns into healthy cycling is our goal. We draw upon academic studies from beyond the cycling world to inform our understanding of what works best for cyclists and apply the knowledge throughout the fitting process. See our links and articles page for some great, albeit dry, reads!
Time's founder designed the first widely accepted clipless pedal back in 1982 as an engineer for Look. The current Time pedals have 5 degrees of float pivoting off of the toe, as well as 2.5mm of lateral float (inward-outward), which gives the pedal a subtle slide-y feeling.
With a background in downhill ski bindings, Look produced the first widely adopted clipless pedal system in 1984. Since then, their pedal system has defined the road clipless category and remains the benchmark which other innovators strive to improve upon. Their cleats are available in 0, 4.5, or 9 degrees of float. Look float pivots from the toe, and cleat release tension is adjustable from light to very heavy.
Speedplay introduced their clipless system later than either Time or Shimano, but rapidly grew in popularity due their innovative, highly functional design. With a low profile, double sided entry, broad shoe compatibility, multiple spindle length options, and, most popular of all, ample and adjustable float, they are a great solution for many riders.
Shimano has different cleat options with either 0, 2, or 6 degrees of float. Unlike the aforementioned Time pedals or the Shimano yellow 6 degree cleat option, the 2 degree blue cleat version doesn't allow for any pivot in the toe, so it feels stiffer while still following the motion of the foot and leg.
Clipless Glossary of Terms:
What one hears the most about in technical pedal design is "float" "platform size" "Q-Factor"
and so on. In the old days the foot was secured to the pedal by the clips-and-straps, working best when the toe straps were cinched down tight. There was a little play in the system based on its design, but any freedom of movement was incidental. Now, with a better understanding of biomechanics the freedom of movement is intentional and each manufacturer tries to address it in different ways.
Float is often the most discussed pedal feature. The point is to have the pedal move with the natural path of the foot as the leg tracks through the pedalstroke. The particular characteristics of this movement are the product of the cleat-pedal interface design, so different designs lead to pronounced differences in the feel of the float. We primarily sell three road systems (Speedplay, Time, and Shimano) each with their own float feel. Speedplay is famous for its ample, adjustable range of float. Time features float that is lateral as well as rotational. Shimano has a firm-feeling float that pivots from the toe, and has ranges of float limit determined by the cleats used. No one float is best, but it is important to understand their differences and to choose according to your particular needs.
Spindle length determines the width of the rider's stance during pedaling ("q-factor," in cycling jargon). The optimal stance is based on pedaling mechanics, morphology (bowlegged?), muscular development, etc. Speedplay offers the widest range of spindle length difference at 1.5 cm, or 5/8", in 4 length options. Speedplay also produces the Determinator (pictured), a fitting tool that allow for very quick changes of spindle length during the fitting process. Shimano also offers a wide spindle option, which is 4mm wider than their standard width.
DOUBLE SIDED vs. SINGLE SIDED
Double-sided entry allows the rider to simply place the shoe over the pedal and clip in, whereas single-sided pedals require the rider to catch the correct side of the pedal with the cleat to engage the retention mechanism. Speedplay is the only road system that has double-sided entry. Shimano and Time make double-sided clipless pedal systems for mountain biking, which many recreational riders use for road cycling.
Light spring tension in the pedal retention mechanism is often a great feature for riders starting out with clipless pedals. It allows for easier entry and exit from the pedal, which can give confidence to the rider during stops and starts. Many experienced riders who don't sprint often, or are lighter, also prefer the feel of lighter tension pedals. The mountain bike pedals offered by Shimano and Time have the lightest-feeling retention mechanism. In addition to their standard models, Speedplay also offers a light-tension version of road pedal, called Light Action.
MOUNTAIN vs ROAD:
All major pedal brands produce both mountain and road pedal systems. While road pedals are not suitable for potentially muddy off-road hike-a-biking on steep mountain trails, mountain pedals are a great option for many road rider. Because mountain bike shoes have recessed cleats and lugged soles, they are much more walking-friendly, which is great for riders who enjoy stopping to smell the roses. Also, most mountain padals offer very light retention, which many riders prefer. The advantages of road pedals are their superior retention for sprinting and very hard efforts, their generally lighter shoes design, and their broader cleat platform, which produces a stiffer, more powerful platform.