For people new to the sport of cycling, choosing the right pedal can be a little confusing, especially if you have been used to using standard flat pedals before.
Whilst there are a variety of different clipless pedal systems used by amateurs and pros alike, Shimano’s SPD and SPD-SL clipless pedals are perhaps the most common versions used by road cyclists and mountain bikers.
In this article, we’ll be comparing Shimano’s SPD vs SPD-SL pedal and cleat systems to help you decipher which is best for your riding.
Shimano SPD vs SPD-SL Pedals: Similarities & Differences
“SPD” stands for “Shimano Pedaling Dynamics” in both systems. Both are “clipless” pedal designs, in which a cleat screwed into the sole of a cycling shoe securely clips into the pedal itself.
Despite the obvious contradiction in the name, these pedal systems are described as “clipless” because they replaced the older system of toe clips and straps that held cyclists’ feet in the pedals before the invention of the clipless pedal.
Both SPD and SPD-SL systems offer a high degree of adjustability in the securing tension, allowing inexperienced riders to start at lower tensions to help them engage and (more importantly) disengage easily as they get the knack of the technique.
More experienced riders will likely prefer a higher tension to help them pedal more efficiently, especially when putting out more power.
Both pedal systems allow a certain degree of float, which is how much lateral movement is permitted when clipped in. This float helps to prevent knee injuries.
Note that while the terms SPD and SPD-SL refer specifically to Shimano technology, the two terms are often used more widely to describe similar or equivalent designs from other manufacturers too.
Shimano SPD Pedals
Though both SPD and SPD-SL pedals can be used by road cyclists or mountain bikers, the SPD pedal has traditionally been favored by mountain bikers.
It has also found a natural home in the growing gravel biking scene.
The SPD pedal connects with a fully metallic cleat that is significantly smaller than the corresponding cleat used for the SPD-SL pedal.
SPD cleats are secured to cycling shoes with two bolts, so are sometimes referred to as “two-bolt cleats.
Shimano SPD-SL Pedals
The additional “SL” label in SPD-SL stands for “Super Light”.
Being lighter, the SPD-SL is primarily designed for road cycling where riders, pro and amateur alike, have an unnatural obsession with all things weight.
The SPD-SL cleat is made of plastic and therefore lighter than the SPD cleat. They are secured to the shoe with three bolts, so are often called “three-bolt cleats”.
The large, stiffer cleats also provide a more efficient power transfer, which is typically more important for road bike racing than for MTB riding.
SPD-SL pedals were only introduced by Shimano in 2003, so are a younger technology than the original SPD system. The SPD-SL pedal also offers a range of float options when combined with different cleats.
These are the main differences between the designs of SPD vs SPD-SL pedals, but these have other implications for how they perform for a cyclist.
Let’s explore those now!
What Are The Advantages Of SPD Pedals?
Double-Sided Engagement
New riders, even those who ride road bikes, are immediately drawn to SPD pedals for the double-sided entry.
Double-sided pedals make it easier to get your shoe engaged first-time, a natural worry for anyone who might have lots of traffic lights on their commute.
No one wants to be fiddling with trying to flip their pedals over with a line of cars revving behind them.
Forgiving In Muddy Conditions
Since they are ostensibly designed for mountain bikes, SPD pedals and cleats are great at getting rid of any mud, ensuring that clipping in and out is rarely compromised.
Walkability
The small, recessed cleats used for SPD pedals allow them to be neatly tucked beneath the tread on the sole of mountain bike shoes.
This makes walking much, much easier compared to the shoes used with SPD-SL pedals. It is essentially just like walking in normal shoes and most MTB shoes can take smooth and rough terrain in their stride.
This is an obvious advantage for mountain bikers and cyclocross riders who often need to push their bikes up and over obstacles while off-road.
Touring cyclists and commuters will also find this feature of SPD pedals priceless.
I have first-hand experience of this on a multi-day tour of the remote Scottish Hebridean islands. I opted to swap the lightness of my SPD-SL pedals for the practicality of SPD pedals.
I knew there would be plenty of exploring on foot whenever we came across a secluded beach that looked like it had hitched a ride on the Gulf Stream from the Caribbean – and I was very glad I swapped SPD-SL to regular old SPD for that trip!
My cycling buddy, who opted to stick with SPD-SL pedals, had to watch every step.
It did mean that I was doing most trips to the bar whenever we stopped at a pub, though, so maybe he won in the end.
What Are The Advantages Of SPD-SL Pedals?
Lower Weight
We road cyclists care about two things above everything else (even more than the length of our socks and our tan lines): power and weight.
This is exactly why road cyclists typically turn to SPD-SL pedals. They are lightweight and the large plastic cleat provides a large, stiff platform to help transfer as much power as possible.
Larger Surface Area
The larger cleat helps to spread the load on the pedal, and a lot of riders feel that it is more comfortable on longer riders than SPD pedals where hotspots on the foot are more common.
The downside of that large cleat is that they tend to protrude from the sole of the cycling shoe, making walking awkward at best – and sometimes downright dangerous on smooth surfaces.
The plastic cleats tend to wear out quicker than the metal SPD cleats, but they are relatively inexpensive to replace and easy to fit with the right Allen key.
Once you have found the right position of the cleat on your shoe it is a good idea to mark it with a Sharpie so that you can replace them in the exact position.
Are SPD-SL Pedals Harder To Use Than SPD Pedals?
Aside from subtle performance differences, perhaps the biggest difference between SPD vs SPD-SL pedals is the latter’s single-side entry.
SPD-SL pedals are naturally weighted so that they dangle in a heel-down position. Clipping in involves pushing the top of the pedal down, and then finding the sweet spot to engage the cleat toe-first, then pushing the heel into the mechanism.
It is hard to visualize and requires a bit of practice – but from experience, I assure you that eventually it will come naturally.
That said, it is not foolproof, and in all my years of riding there are still occasions when I find myself swearing at my pedals and my clear lack of coordination.
On those days, I miss the simplicity of the SPD pedal – so yes, I would argue that SPD-SL pedals are slightly trickier to use for beginners than SPD pedals.
SPD-SL vs SPD: Which Should You Choose?
Conventionally, mountain bikers tend to use SPD pedals, while SPD-SLs are considered road pedals.
For mountain bikers, this generally makes sense, but for road cyclists, there are certainly times when there can be benefits to switching to SPD pedals.
Personally, I am not one of those riders who are precious about the “rules” of road cycling.
I will happily wear odd socks if I can’t find a matching pair, I have been known to wear leg warmers without corresponding arm warmers – and I have no problem with using SPD pedals on my sleek road bike.
If I’m going on a ride on which I am more interested in speed, however, the SPD-SL pedals are swapped onto the bike. You can feel the improved power transfer and they are more comfortable on those long rides.
If I am going on a long cycling trip and I know I will be doing a lot of walking off the bike, especially if I am mixing it up with boats and trains, then the walkability of SPD pedals wins every time. They are just more practical.
They are also a great introduction for getting to grips with clipless pedals if you have only ever used traditional flat pedals. The double-sided entry helps to quickly build confidence, making the move to SPD-SL pedals down the line a lot less daunting.
The pedals are easily changed with the right tools, and having both at your fingertips gives you the best of both worlds.