The days of deciding to go clipless or not are long gone – the efficiency gains of clipping in are indisputable. The question now is, which type of clipless pedal is best? Taking a look at the evolution of the mountain bike pedal may help make that answer more clear.

Japanese giant Shimano started it all in 1990 with the creation of SPDs, which stands for Shimano Pedaling Dynamics. The point was to create a pedal and shoe with a recessed cleat to make the walking and hiking demanded by off-road biking easier. Look, TIME, and Adidas had already come out with clipless systems, but they were for road biking. Shimano had the first system for mountain biking, and SPDs worked so well that they catapulted Shimano to off-road pedal market domination.

Critics claimed the one oversight in SPD design was mud clearance. This was a legitimate concern on the professional circuit in Canada, the UK, and northern Europe where racers were frequently forced to dismount and run muddy sections. Upon remount, the racers’ cleats were too gummed-up to clip back into their pedals. Shimano responded by adding a small allen key adjustment to the pedal for greater spring tension release, and the race to create superior mud-shedding pedals began.

Crank Bros’ Egg Beaters, which debuted in 2002, were among the most successful at grabbing Shimano’s off-road pedal market share in the U.S. Egg beaters are SPD-compatible and have four entry points, instead of two, making for quicker entry. Their minimalist stainless steel design (there are only 13 parts per pedal) gives the mud less to stick to, and also serves to scrape it from your cleat as you enter the pedal.

Crank Bros also added more float – eight degrees compared to Shimano’s six which has nothing to do with mud clearance, but with allowing movement in the pedal to reduce stress in the knee joint. Shimano responded by bumping their float up to eight degrees, while arguing that Egg Beaters were nearly impossible to ride unclipped since they didn’t have a “body.” To which Crank Bros responded, you would never need to ride them unclipped. Yet Crank Bros went on to create the Candy, and the Mallet, both pedals with platforms, which could be ridden unclipped.

Back and forth the two have gone for nearly a decade now. Meanwhile, Speedplay’s Frogs are the latest pedal flavor du jour. Their proprietary cleats (which will fit into SPD-style shoes) are immune to mud since debris is pushed out each time you engage the pedal. The Frog has a single retention mechanism in the cleat instead of two redundant mechanisms located in the pedal and engagement security doesn't depend on spring tension. They also have a knee-friendly float of 20-degrees. CEO Richard Bryne, the inventor of Frogs, elaborates, without giving away trade secrets. “Many clipless pedal systems force you to overcome a 'spring-restrained' jaw system when engaging and disengaging. This action not only makes it harder to get in and out of the pedals but can also put strain on the knees. In contrast, our 'true-locking' mechanism doesn't rely on spring tension for engagement, thereby making the system both user and knee friendly.”

Funny thing about Frogs is they are not new. They’ve actually been around since 1992. The evolution of the mountain bike pedal has seemingly gone full circle, making the answer to the original question as to which is the best clear as mud.