There is a wide range of pedal systems on the market, so how do you choose one that is best for your needs? And why does your choice of pedals matter?
A pedal system consists of the pedals and cleats, which are bolted to the bottom of your cycle shoes. Most road systems use 3 bolts to attach the cleat to your shoe, however the cleats from one manufacturer aren’t compatible with the pedals of another. Speedplay cleats can be attached with the standard 3-hole mount (which most people use) or can be attached with 4 holes (although few shoe manufacturers actually offer a 4-hole cleat mount). Mountain bike cleats are far smaller and use a 2 hole system. The main advantage of a mountain bike pedal system for a road cyclist is that the cleat is recessed in the shoe making it far easier to walk around. Hence touring cyclists (on “randonneur” bikes) tend to favour mountain bike pedals / cleats for their bike.
From a bike fitting perspective, there are a range of features that you may want to consider. Given that all power is transferred into turning the cranks via the cleat and pedal, the choices you make here have a significant impact on your cycling. Whatever system you choose, the key thing is to ensure that your pedalling action is maximally efficient and biomechanically correct, otherwise the millions of circles you make each year will likely do you some harm. If the positioning is wrong or poorly adjusted, knee pain is a common consequence.
Correct biomechanics with respect to the pedal means that leg moves in one plane – the foot, knee and hip joints are lined up directly above each other and there is no rotation or angling of the knees inwards or outwards. When looking from the front the entire leg moves up and down in a straight line (see photos below). So when selecting a pedal system that best suits your individual body, we need to choose one that allows / assists the pedalling action to be in nice straight lines. When the pedals or cleats force your knee into rotation (either inwards or outwards), an overuse injury is often the result.
Here are the different variables to consider with respect to bike fitting and pedalling mechanics (weight of the pedals etc doesn’t affect your position but might be something to consider as well):
1. FLOAT (ROTATION) or FIXED:
Float is the amount of rotation your foot can have when clipped in, whereas a fixed cleat means you have zero rotation available. Float is important for most riders as the rotational movement at the pedal allows you to absorb some rotational forces that may occur from time to time when you’re riding. Now I know I have just said “but rotation shouldn’t happen” with ideal mechanics. However to have ideal or perfect mechanics all the time we need to have a lot of things working optimally, such as:
Good balance between right and left legs;
Good joint function and alignment in your spine;
Flexibility – do you stay adequately flexible ALL of the time, or sometimes get a bit tighter after a hard training block?
Good bony alignment: some people have bones that simply aren’t straight and this can influence our technique. This can be true anywhere in the leg from the feet to the pelvis.
Since it requires a lot of proactive effort to keep your body operating “perfectly” all the time, then from time to time things may become tight and cause our pedalling mechanics to change. This is why the pro riders have so many sessions with their soigneurs and physio’s! If everything is operating perfectly (or close to) then float may be unnecessary. However, since we can all get tighter (eg with training) or weaker (eg without training), these changes can lead to less than perfect pedalling technique and some rotation creeping into our pedalling stroke.
If your pedals do not have any float at all (known as “fixed”), then your knees are forced to absorb any rotation present. Knees generally get sore when this occurs! So having around 5° float in your pedals is useful for most riders, although as always there are exceptions. Elite level track riders, for example, who make the effort to stay on top of their mechanics by remaining flexible and strong, generally benefit from a fixed pedal, whilst someone who has previously had a severe tibial fracture and may now have some mal-union (ie the bone is no longer straight) may require more float than 5°.
2. AXLE LENGTH:
How wide the pedal platform is positioned has a very important role in helping to align your feet under your hips and knees. If the axles are too long the pedals force your feet wider than your hips, causing your knees to rotate inwards. Similarly if the axles are too short your feet are narrower than your hips causing your knees to pop outwards when pedalling. Note that crank and bottom bracket width (which can vary between group sets and frames), and medial-lateral placement of the cleat on the shoe also affect whether your feet are positioned directly under the centre of your knees and hips.
Currently the main two companies offering different options for road pedal axles are Speedplay and Keywin. Shimano offers a 4mm longer axle and Look has the capacity to add 2mm to its standard axle length. In most pedal systems the cleats can be adjusted in the medial-lateral plane by +/-2mm, although Keywin does not offer this. The standard width tends to work well for many people who have “standard width hips”, but if your hips are a little bit wider or more narrow, then you may benefit from pedals which have a corresponding change in axle length.
3. STACK HEIGHT:
Stack height refers to how tall or thick the pedal and cleat is (and to this we can add the sole of your cycle shoes). The taller this “stack” is the higher your saddle needs to be and the less efficient your pedal stroke due to increased rocking torque. In general a smaller stack height is better because it’s more efficient and more stable.
NB: if you change shoes or pedal brands this should trigger a full bike fit review as not only will your cleats need fitting but your saddle and thus your handlebar position may need to change.
A recent client discovered how important this can be when he bought some new shoes and pedals. He didn’t realise the difference in stack height from his old set-up to the new one was a massive 14mm lower. By not changing his saddle height his knees were forces into more extension at the bottom of the pedal stroke as his saddle was now far too high. This caused in pain behind the knees as his hamstrings were overloaded. This is another great example of how changing one thing on the bike changes everything else.
4. ADJUSTABILITY OF CLEAT POSITION:
Different pedals allow you to adjust cleat position to differing degrees. Cleat position can be adjusted in 3 planes:
Fore-aft;
Medial-lateral (most companies offer +/-2mm);
Rotation.
Put simply Speedplay offers the greatest level of adjustment in all 3 planes, so if you require more finesse in positioning your cleat then this might be the pedal for you. Speedplay also offer a base plate extender kit to further increase the range or fore-aft positioning. Keywin offers no medial-lateral adjustment – for this brand you need to choose the correct axle width to achieve optimal medial-lateral placement of the feet under your knees and hips.
Speedplay cleats (see image above) consist of 2 parts. The black base plate (blue arrow) allows fore-aft adjustment of the cleat on the shoe via 3 screws. The yellow cleat (red arrow) attaches to the base plate via 4 screws and permits medial-lateral adjustment. It also houses the spring (green arrow) whose tension keeps you clipped into the pedal, along with 2 additional screws which permit adjustment of rotation (pink arrow - screws located under the walkable yellow cover).
How do you measure and fit cleats? That's what a bike fit is for as many of the measures aren't possible to take on yourself whilst pedalling.
The table below lists many of the features you may wish to consider for the most common road pedals in Australia. Xpedo, Issi and Crank Bros also make pedals with different axle lengths available.
