Stance width: what it is and why you should care
Digging into the often overlooked bike fit dimension
Stance width is often ignored, simply because most equipment manufacturers have failed to develop suitable products.
For any bike fit, we’ve come to expect a certain number of things to happen, and for them to happen in a certain order. An evaluation of our body and our riding is followed by choosing a saddle, getting our shoes set and then we pedal.
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Saddles are tilted, moved forwards and backwards, up and down and eventually our engine is comfortable.
The fitter moves to the front of the bike to manage the cockpit. Handlebars are rotated, shifters are set, brake levers dialed and finally the stem finds a new home.
More advanced fitters will evaluate the hip, knee and ankle, and some of them are skilled enough to properly use wedges (forefoot or heel) inside or outside of our shoe to establish alignment.
And we’re done, right? Well, for a lot of folks, yeah. But this isn’t because you’re really done, it’s because their hands are tied behind their back. Some of the fitters that use wedging are doing so simply because they don’t have the proper tool at hand — the ability to adjust stance width.
What is stance width?
Stance width is a pretty simple concept. It’s the distance between the left and right pedal, if we were able to measure in a straight line. Obviously, the opposing nature of crank arms doesn’t make this easy, and the actual number is pretty irrelevant (except to transfer a fit).
While the number may be generally useless, what does matter is how your current stance width works with or against your body.
Stance width can be affected by several things: type of bike (road, mountain, etc.), type/brand of pedal, crank brand or model, shoe make and model, and where you mount your cleats on your shoe.
What changes stance width?
Frame construction is one factor that has stance width implications. Road bikes, due to their engineering, can have a narrow profile. Meanwhile, mountain bikes with their wide tires, wide chainstays and swingarms are forced in to a slightly wider profile. Ultimately cranks are forced to make space for the structural aspects of the frame.
Generally speaking, the manner in which cranks affect stance width has settled upon a very narrow range for road and mountain bikes. But there is a perceptible difference between the two disciplines, with road being narrower than mountain. This is what has the industry has named crank ‘Q-Factor’.
However, it’s become such a non-factor that manufacturers are rarely even publishing these numbers anymore. So for the sake of practicality, there are more important considerations.
Shoes, pedals and cleats are all that remains to facilitate a change in stance width.
For the most part, shoe lasts are typically built with the centerline of the cleat falling under the third metatarsal, so this too fails to manipulate stance width. Although between brands there can be variation, so be on the lookout when you’re trying to transfer a position with new shoes.
That leaves us with pedals and cleats.
Every pedal system, regardless of off-road or road use, has a way to manipulate stance width at least a few millimeters. SPD cleats have a lateral adjustment — cleat to the inside, foot goes out; cleat to the outside, foot goes in. Same goes for any three-hole pedal systems.
Keep in mind, if the cleat is not centered on the shoe there is a resulting torque on the shoe that can cause it to twist. This can be problematic biomechanically, or it can cause your equipment to wear unevenly or fail to function properly.
And what if you need more than a few millimeters? And how would you even know?
Is my stance width good?
When you pedal, do you have good hip, knee and foot alignment? If so, then chances are your stance width is appropriate.
But what if your knee swings out at the top of your pedal stroke or it’s bowed out at the bottom of the pedal stroke? Does your knee stay inside your foot at the top or bottom of the pedal stroke? If you answer yes to any of these, you might ask a trained eye to have a look.
Ideally your hip, knee and foot form a fairly direct path — as direct a path as you have off the bike. In short, you should look on the bike like you look off the bike.
Consider all the pedal strokes you take on a ride. For a refresher, if you ride for an hour pedaling at 80rpm that’s 4,800 times your knee is exposed to a load. Do the math that corresponds to your rides and it’s easy to see that this matters.
Delivering power to the pedals is a challenge for us all, so why not create a mechanical system that reflects your biomechanical system? It will prevent injury and help deliver a more effective pedal stroke.
Real solutions to stance width adjustments
So now you’ve realized you need more than just a few millimeters and your cleats alone are not enough adjustment.
Speedplay and Keywin are two of the only companies that believe your stance width matters, and I applaud them for this.
Keywin makes different length spindles for both of its road pedal models. Speedplay makes models for road and off-road.
Both companies even offer a kit that can be used during a fit session to find the most appropriate stance width. From there, an order for your specific stance width recipe can be created (and no, they don’t have to be equal left and right).
There are two other more basic options: pedal washers and axle extenders. Pedal washers can buy you an extra 3mm assuming your pedal still has enough thread engaged.
Axle extenders put you out a whopping 25mm. But be warned, some crank manufacturers will void a warranty if too many washers or axle extenders are used! Pay close attention to carbon crank models.
Also of relevance is the fact that some pedal brands have a few millimeters of stance width difference between models, resulting from material selections and an attempt to shave weight.
The only way to ensure you get the ideal stance width and proper support is to have your foot under your driving leg. Maybe you can achieve that with a cleat move or a new pedal axle.
But for the hundreds of thousands of pedal strokes you’ll be taking, stance width is not a topic that should be overlooked, ignored or underestimated.
