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Difference in efficiency between SPD and SPD-SL
Let’s compare how much the power efficiency differs between SPD and SPD-SL in terms of the connection surface between shoes, cleats and pedals.
Looking at the connection between pedals and cleats, SPD is connected to the pedals with a 3cm x 1.5cm surface, while SPD-SL is connected to the pedals with an 8cm x 7cm triangle. In terms of area, the SPD-SL is 6 times larger (4.5 cm2 vs. 28 cm2). Not all of the cleat surface is connected to the pedals or shoes, but it is a big difference.
The connection between the cleats and shoes is also more secure, with three bolts on the SPD-SL compared to two bolts on the SPD.
Also, the sole of the SPD-SL shoes is made of carbon, so you can use the entire sole of the shoe instead of the pedal surface like SPD or flat pedals, which is a plus in terms of power efficiency.
In this way, comparing SPD and SPD-SL, it can be said that SPD-SL can transmit power more efficiently.
Assuming that the SPD-SL can transfer power more efficiently, the advantage of higher efficiency is that it is less tiring (not that you won’t get tired).
Bindings are a mechanism that allows you to use your pulling foot for greater pedaling efficiency, but the more solid the connection surface is during the pulling foot, the less power loss you will experience, so you can pedal with less power in total. The “ability to tread with the entire sole of the shoe,” as explained earlier, is also a plus in terms of power efficiency.
Of course, the SPD-SL won’t make you dramatically less tired, but on long rides of over 100km, you will probably feel the difference as you approach the end of the ride.
Which one is easier to take on and off?
It is often said that binding beginners should start with SPD and then move on to SPD-SL, but even SPD-SL is surprisingly easy to remove if you use yellow cleats that are less adherent.
The SPD-SL is “hooked” to the pedals, so you may not be able to fix it well until you get used to it.
This is a matter of getting used to, and even if you can’t fix the pedals well, you can still pedal without fixing them, so you can start pedaling after fixing them firmly at traffic lights or on sidewalks.
In this sense, there is not much need to choose between SPD and SPD-SL for the reasons of “easy to come off” or “easy to fix”.
Different types of cleats for SPD-SL
There are three types of SPD-SL cleats, each with a different color and play. The cleats with more play are easier to remove.
In the case of the SPD-SL, the play on the left and right side also means that your foot can move left and right even though it is fixed to the pedal, so if you are not used to it, you may not be pedaling straight and your pedaling efficiency may decrease.
The yellow SH11 cleat is as easy to remove as the SPD.
The difference between SPD cleats
There are also two types of cleats for SPD, normal and multi. SPD cleats are easy to remove, but multi can be removed in more different directions, which is good if you are afraid of binding.
Which is better, SPD or SPD-SL?
SPD and SPD-SL have different purposes.
SPD is “the standard for MTB and other rides where you have to take it on and off frequently,” while SPD-SL is “the standard that prioritizes power efficiency at the expense of walkability.
In long rides of more than 100km, the time spent pedaling is much longer than the time spent walking, and it is more comfortable to minimize power loss in order to pedal for a long time. For this purpose, SPD-SL is the best choice.
On the other hand, if you are cycling or pottering for 20km or so, stopping frequently at stores or sightseeing spots, the SPD is the best choice because you will spend less time pedaling and more time walking. SPD, with its cleats embedded in the sole, also has the advantage of not damaging the floors of stores and facilities.
Does a road bike have to be an SPD-SL?
I often hear people say, “If it’s not an SPD-SL, it’s not a road bike.” But a road bike is a road bike whether it has SPD or flat pedals. Of course, SPD-SL is more in line with the concept of “riding long distances with ease”, but that doesn’t mean it has to be SPD-SL.
It is best to decide according to your own use and how you want to run.
Do SPD shoes feel the same as athletic shoes, or is SPD-SL hard to walk in?
SPD is said to be easy to walk in, but it still has cleats and a hard sole, so the feeling of walking is completely different from athletic shoes. It’s easier to walk and less slippery than SPD-SL, which has exposed cleats and no grip on the sole, but it’s not impossible to walk in SPD-SL.
However, the cleats of the SPD-SL are made of plastic and are not designed for walking, so walking on asphalt will tear the cleats to pieces. On the other hand, the cleats of SPD are made of metal and the cleats are embedded in the sole, so it can be said that the cleats are less likely to fall apart when you walk.
Is it possible to convert between SPD and SPD-SL?
Shimano has released a conversion adapter to connect SPD to shoes for SPD-SL, so it is possible for the shoe side to convert SPD-SL to SPD. The reverse is not possible.
Also, there are no such conversion adapters available for the pedal side, so it is not possible to convert SPD pedals to SPD-SL or vice versa.
Are there pedals for both SPD and SPD-SL?
There are pedals that can be used for both SPD and flat, or SPD-SL and flat, but there are no pedals that can be used for both SPD and SPD-SL.
On the other hand, there are shoes that can be used for both SPD and SPD-SL. The advantage of these shoes is that they can be connected to both types of cleats, so even if you change pedals, you can still use the same shoes.
However, in the case of dual-use shoes, the cleats are exposed, unlike SPD-specific shoes, so there may be little point in using SPD shoes.