Okay, so first off SPD stands for Shimano Pedal Dynamics. Which, on its own, doesn’t actually mean a whole lot, but to you and me it means clipless pedals.

The other confusing thing is that they’re called clipless pedals when you clip into them. Well, back in the day pedals actually had toe clips to keep your feet attached, so clipless means pedals without toe clips. And that’s as opposed to flat pedals, which are just platforms for your feet with no attachment whatsoever (other than maybe emotional attachment to a set you particularly like, perhaps).

The SPD pedal comes in two parts: the pedal itself and the cleat, which is the attachment mechanism that fits onto the bottom of your shoe. The classic SPD uses a small cleat with a two-bolt attachment, used with shoes that have soles that look like this:

But Shimano do have another system, called SPD-SL, which is their pedal/cleat combo for road riders. Those use a three-bolt system, derived from LOOK’s original clipless pedal, and soles compatible with SPD-SL cleats look like this:

[image of SPD-SL compatible sole]

Other than the cleat system, the fundamental difference between SPD and SPD-SL is that SPD pedals are almost all double sided, with a clipless mechanism on both sides, while SPD-SL are single sided, meaning you can only clip into the one side of the pedal. In practice that means SPD pedals are generally better for anything that involves lots of clipping in and out – which is why most urban and MTB clipless pedals use the SPD system – while SPD-SL are for longer duration rides that involve less stopping (road riding, basically).

The great thing about SPDs is that because they’re double sided it’s pretty easy to get going from a standing start if you’re new to clipless pedals. With SPD-SLs being single sided, there’s degree of precision required and only one side of the pedal to get it right, meaning if you mess it up you could be on for a one-way meeting with the tarmac. SPDs on the other hand, gives you two sides to clip into, and some even have a flat platform surrounding the clipless part so you can pedal even if you fail to clip in properly.

The other fundamental difference between the two is in the cleat. SPD cleats are small, neat and designed to fit into the sole of a shoe so that you can still walk easily. SPD-SL cleats are large and stick out from the bottom of a road shoe, making it trickier to walk and a little uncomfortable as well. On the plus side, they give a large, solid feeling contact point with the pedal and are super comfortable under foot even when pedalling for hours. So it’s really a case of finding the right system for the riding you want to do.

Whichever system you choose, the best advice we can give you is to make sure you practise clipping in and out before you take the bike out in anger. Just sitting next to a wall holding yourself up and clipping in and out for a few minutes will be a big help, you basically want to make that motion second nature because eventually you’re going to need to do it under pressure and wont want to mess it up.