When the pedal system changes, what happens to bike fitting?

Just when you thought the only stable thing in the universe - both physically and metaphorically - was Shimano’s SPD-SL pedal and cleat system, in comes Shimano with a new release to shake things up.

For FORM, this is big news. Our lives revolve around the foot/pedal interface, and when we heard about the release, we couldn’t get the information fast enough. The cleat and pedal are fundamental to bike fitting that any significant change to the system has our full attention. But what exactly is the SPD-SLR, and why does it matter?

The SPD-SL has been Shimano’s road pedal platform since 2003, making this the first major evolution of an interface that has been familiar and widely popular to riders and fitters for more than two decades. Knowing how well the SPD-SL works, we were curious to see what would constitute an improvement.

So, what has changed?

At its most basic, the headline change is reduced stack height. Shimano has redesigned the pedal and cleat interface to bring the rider’s foot closer to the pedal axle, alongside a lighter cleat and revised engagement characteristics.

From a bike fitting perspective, the reduction in stack height is also the most significant change.

Lowering the foot relative to the pedal axle can have benefits, and stack height is something that should always be considered when designing and fitting a rider’s foot/pedal interface. Whether that alone warrants an entirely new system is, in the eyes of FORM, a more debatable question.

Shimano has prioritised this, alongside other objectives such as weight and engagement.

But when you have a system that has been widely used and highly functional for more than two decades, it is natural to ask: what are we actually trying to improve?

And, perhaps more importantly for us, what happens to bike fitting when the interface itself changes?

The new system is clearly designed to work as part of a complete shoe, cleat and pedal ecosystem, with Shimano's new shoes incorporating additional fore/aft adjustment. It’s a winning combination in many mainstream scenarios and, for the rider who fits that system well, a compelling (yet more costly) package.

What does that mean for the individual rider?

This is where the detail starts to matter, from a bike fitting perspective. 

Shimano has put a lot of thought into the new system, particularly when combined with its new shoes. But does it satisfy all fitting needs, or is it designed primarily around the mainstream rider and those who take their inspiration from professional setups?

From our perspective, there are some notable omissions. Without the new Shimano shoe, the pedal and cleat system itself offers very little fore/aft adjustment. That’s significant because a more rearward cleat positioning has become increasingly common in modern bike fitting, particularly amongst riders looking to reduce demand on the ankle and calf or improve stability through the foot/pedal interface.

There is also limited scope for additional medial/lateral adjustment, and the cleat’s ability to be rotated  (as distinct from its float) to create a more pronounced heel-in or heel-out foot position, is limited. These are all important parameters that we regularly encounter in our work with riders and bike fitters.

Set against the outgoing SPD-SL cleat, the difference is clear:

These measurements are for the cleat alone and do not include the shoe.

None of this makes the SPD-SLR a bad system. Far from it. For many riders, the new combination of pedal, cleat and shoe will work extremely well. But any change to the interface inevitably affects the fitting options available to riders and fitters.

And this is where the trade-off becomes important: the lower stack height has come at the cost of adjustment in the cleat itself. Lower stack is one part of the equation, not the whole of it. The fitter still needs to consider cleat position, foot stability, alignment, leg length, stance width and the individual rider’s requirements.

A system that works brilliantly for one rider may leave another wanting more adjustment. That’s why, at FORM, we come back to something we talk about constantly: there is no one-size-fits-all solution to bike fitting.

Looking beyond the cleat

Adjustment in the cleat only tells part of the story.

A rider who already needed more than the SPD-SL cleat could offer would have an extender plate in their setup anyway, so the smaller range in the SPD-SLR cleat changes very little for them. For riders who used to find their position within the old cleat’s range, an extender plate (or Shimano’s new shoe) now fills the gap. Either way, the new system offers the best of both: the adjustment the rider needs, alongside the lower stack height of the SPD-SLR.

We asked earlier whether the change was necessary. Perhaps that’s the wrong question. Shimano has chosen to prioritise certain objectives, and for many riders the result will work well. However, the requirements of a professional rider, a recreational rider, an ultra-endurance athlete or someone with a particular anatomical or biomechanical consideration can be vastly different.

The more useful question is whether the system, as part of the wider foot/pedal interface, gives the individual rider what they need. If it does, great. If the answer is “not quite”, that doesn’t mean abandoning the new system. It means looking at what additional adjustment is required.

The lower stack height is a welcome development. Bringing the foot closer to the axle has clear potential benefits, and Shimano has combined this with a new shoe that provides additional fore/aft adjustment. From a fitting perspective, though, we’d argue that adjustability is just as important as integration. The best system isn’t necessarily the one with the fewest components or the lowest stack. It’s the one that gives the fitter enough freedom to put the individual rider where they need to be.

And that’s ultimately the question we ask of any new technology: does it work for you?

What are your options?

Whatever pedal/cleat system you're using, there are still circumstances where you need more adjustment. That's where additional fitting tools can be useful.

FORM's existing SPD-SL extender plates were designed around the taller stack height of the previous system, so those versions aren't compatible with SPD-SLR. However, our version with flush threaded inserts is compatible with the new Shimano cleat.

Need more rearward adjustment? Combined with the XPR, the new Shimano pedal and cleat can provide additional rearward adjustment on a wider range of shoes, with up to 8mm or 20mm depending on the setting.

Need more fore/aft and medial/lateral adjustment? Combined with the XPS, riders can achieve a similar fore/aft adjustment range to the Shimano shoe while gaining an additional 10mm of medial/lateral adjustment.

And all of this can be achieved while retaining the lower stack-height benefits of the new Shimano system.

Of course, extender plates aren't the only fitting tool. Depending on the rider, shims, wedges and other interface modifications can all play a role in establishing the right position, stability and alignment.

In other words, the new Shimano system doesn't have to be an either / or decision. The lower stack height can be retained while additional fitting parameters can be introduced where the individual rider needs them.

For us, that's the exciting part of developments like this.

The foot/pedal interface continues to evolve, but the fundamentals of bike fitting don't change.

Every rider is different. So technology should give us more ways to work with those differences, not fewer.