Apex dynamic bike fit system

An in-depth look at the British system with founder Ceri Pritchard

The new Apex bike is an advanced bike fitting system that's also quite simple in its execution. BikeRadar visited OnitSports to meet Apex Bike Performance founder and ex-pro, Ceri Pritchard, to find out more about the best of British bike fitting.

The defining characteristic of the Apex – a static bike clad in a carbon shell – is its ability to change geometry as the rider pedals and, when combined with power, heart rate and torque effectiveness measurements, give a concrete output of the athlete’s position and gains after fitting.

The fit bike is similar to Guru's Dynamic Fit Unit that can be digitally adjusted while a rider pedals. Other fit companies, such as Retül, have manually adjusted fit bikes like the Muve where fit coordinates are measured in other ways.

“What you find is that a lot of people will go and have a Retül – or something similar," said Pritchard, "they'll be given a position, put it on their bike and slowly over the next six months, they move back to where they were originally. That’s not to say it’s a worse position, but there’s no proof that it’s better.”

“What we’ve found is that when we say, ‘We’ve just gained you 15 watts for nothing’, they’ll stick with it and keep using it.”

The position moves with the rider in place, helping to give a great fit more quickly and easily:

The Apex might look sci-fi, but it's as easy as riding a bike

With the potential to gain some much-needed wattage, we clipped into the Apex and were immediately struck by its simplicity – no trailing cables, stuck-on dots or bike-clamped on a turbo. It’s just clean, easy and doesn’t distract. It also feels surprisingly road-like as you’re cranking.

Pritchard first gave a demonstration of how the Apex can fit into other setups, in this case, a simple USB camera paired with the free Kinovea video manipulation software to check cleat alignment.

Then it was up to race pace effort for an Ironman bike leg – power shown on the stem’s display – and after a warm up, the whirring of motors began as Pritchard tweaked the position by miniscule increments.

We weren’t shown the changes as they happened, so as not to subconsciously compromise the fit, but after 20 minutes of tiny adjustments and positioning experiments, our power had increased around 15 to 20 watts for the same heart rate, which is a big difference in anyone's book.

We like the system's ease of use – it's certainly less complicated than a Retül fit and it's so much quicker not having to hop on and off. It's also really reassuring to be given solid data as to what's changed, which gives peace of mind on the road with no second-guessing of position. The simplicity of the Apex also means repeat visits would put the bike in exactly the same place, without being compromised by Retül's sticker placements or manual measurements of other systems, which could skew results. Of course, the efficacy of the fit is more about the fitter's expertise than the system, but the Apex could allow even the best fitters to get better results – thanks to the instant feedback from experimentation – and save a lot of time, while leaving cyclists happier that their position is correct following a fit. 

We’ll be looking to see if these increases in wattage stick as we adopt the position long term, but we’re optimistic about the figures. Considering the only alterations were moving the bars up 10mm and moving the saddle down a few mm, it’s an impressive tally – and underlines how important small changes in fit can be.

But what exactly contributes to the improved performance an Apex fit can offer most cyclists?

What’s in it for riders

The promise of higher watts is a big win for riders, so how could such an upping of power come from a bike fit – especially when the set-up feels ‘right’ to begin with?

Apex Score

Combining the Apex’s almost infinite on-bike adjustment with its built-in power meter and heart rate outputs an Apex score – an indication of the efficiency of the current setup.

“In the hands of an expert who’s already got a system, it enhances what they’ve got because it gives them the figures to back it up. If it’s used as a standalone system, it just allows you – as a fitter – to quantify what you’re doing in the first place,” said Pritchard.

What this also allows is the finding of a window within which the rider can be positioned without it negatively impacting on performance.

Meet the apex bike fitting machine:

The Apex score is a balance of effort – via heart rate – and power output. As the fit changes, the figure does too

“From a biomechanics point of view, people aren’t symmetrical and nobody has got two legs that are exactly the same length; there’s always going to be some deviation – it’s just the amount we’ve got that causes an issue," Pritchard went on.

“On top of that, the human body is very adaptable. I could put the saddle up or down 100mm and you’d still be able to ride it, but when we’re trying to operate right on the cusp of our very highest performance, then all of a sudden, we’re not as flexible as we might think. Performance drops off incredibly quickly if you’re on either side of that window.

“Our window of perfection is very, very small, hence the reason very small changes make such a difference. A lot of people say they move 2 or 3mm on the saddle anyway, but the point is they’re moving that window. People move on the saddle all the time, but you need to make sure the window they’re going to move in is always going to be the best for them. You don’t want a position on the saddle where it’s going to be detrimental. So that 2 or 3mm becomes critical.”

What about the effect of different techniques such as ankling on the fit?

“Technique does make a difference on the bike, but the aim is to set people up so that they perform the right movements naturally rather than consciously doing it. It’s like a spell check – you can correct everything after and that works, but you’re better off teaching someone to spell right in the first place.”

Specific intensity fitting

Position differs subtly when riding at different intensities. The Apex’s ability to change position with a rider aboard – and measure power and heart-rate changes – means a fit can be specified to the type of riding it’s needed for.

“My TT bike was my most uncomfortable bike when just riding easy,” said Pritchard of his days as a pro, “but when I put the power down and got into the zone it fitted like a glove.

“So if you want to fit someone at their FTP, it becomes crucial to hold them there. You can’t get someone to ride at that level, stop them, make a change and get them back on because you need another 10 or 15 minutes to get back up to the right level and into the position they were riding. To keep doing that isn’t practical.”

This specificity means the correct fit – and peace of mind that goes with that – for whichever event your doing from upright all-day sportives to sharper, head down TT efforts.

Torque efficiency

Perhaps the biggest ‘instant gain’ offered by the Apex comes courtesy of the power meter’s constant torque measurement.

Designed and built specifically for the Apex, the axle-based power meter features 10 strain gauges on each side (eight for measurement, two for temperature compensation) and samples much more regularly than standard units.

“The difference with the power meter is that any ANT+ based power meter will only take a reading three times a second, which is averaged and sent to the head unit. With the Apex, it doesn’t update on time, it updates on the actual rotational movement – it does it 256 times per revolution. So if you’re running at 120 rpm, it’s running at about 550MHz, so it catches a lot more data.”

This ultra-fast refresh gives a continually updated display of the torque being applied by each leg and crucially, where it’s not being applied. The Apex lets the fitter know when there’s negative torque – the infamous dead spots in your pedal stroke.

Just visible – the blue and red torque readings moved away from zero where they cross at the bottom:

The torque analysis allows a good fitter to turn negative torque into a positive – see the blue and red crossing point at the bottom moving away from the white zero circle

“Almost every rider – if not all – has got negative torque on the backstroke. That’s not a bad thing; the only time you going to be totally positive throughout the entire stroke is when you’re out the saddle climbing or when you’re sprinting," Pritchard explained.

"The reason you only do it then is because the cost in efficiency to be able to have that constant positive is too much. If you try and do it all the time, you’re going to pop very quickly.”

The common dead spot that can be addressed is top-dead-centre at the highest point of the pedal stroke.

“Again, most riders have a top-dead-centre dead spot. There are people who’ve tried to rectify it with oval rings. I think they probably do work a little bit, but the trouble is, unless you’ve got a piece of kit like this to be able to find out where that dead spot is and how much it needs to be changed by, the oval ring would have to be personalised for every person to have the benefits that they claim," Pritchard went on.

“The beauty of the Apex’s torque output that is that it allows you to get a really, really good position on the bike because you can see where your top-dead-centre is, see if there’s a dead spot and see that you can turn that into a positive.”

True leg balance

Thanks to the true left-right measurement of the Apex and its ultra-fast refresh, the imbalance between each leg is also easily visible and can be tracked as intensity changes.

“We don’t normally show the client the balance, because seeing it makes everyone trying and compensate, but as a fitter, you can tweak the position to get the balance as close as possible.

“Sometimes you just can’t close it down completely – the Apex can tell you something’s wrong, but not exactly what it is, but you can then tell athletes to get to the gym over the winter and work on strengthening one leg or the other.”

The telemetry is streamlined into need-to-know figures including the torque graph, separate leg power and the apex score:

Our leg balance had a difference of around 20 watts, which is quite common according to Pritchard

On top of this, Pritchard’s experience with British Cycling means the Apex comes loaded with ramp testing to help quantify performance gains.

“You’ve got the automatically controlled resistance and a really accurate power meter, so you may as well do the ramp testing as well," he said. "The software comes preloaded with three different ramp tests, which are based on the ones British Cycling use – I put all the ones from when I was on the BC squad into the bike.”

The end result

Pritchard's assessment is that a bike fit will – perhaps unsurprisingly – always come down to how good the person doing it is.

"I don’t doubt that you can get a really good fit from a Retül system, as long as the guy doing it is someone who has the knowledge. But I think that a lot of the systems that are out there at the moment are baffling. There can be 20 pages of reports that people don’t understand," he said.

“Ours gives before measurements, after measurements and exercise prescription. It tells you what you need to know.

“You go to most bike fits, where you don’t get figures at the end, and if they don’t find anything, you’re none the wiser. But at least if you walk away knowing that there’s nothing more to gain from your position, you can focus your efforts somewhere else.”

A good bike fit can be expensive – but, according to Pritchard, it’s very much worth doing. “Anything you can do that improves you instead of your bike will always give you much better gains than buying new gear," he said.

“Everyone should have one fit a year because you do change. Ideally you’d have one in the winter and one when you’re coming into the racing season again. Your make up changes coming from a winter off-season to on-season. You might change by five or six kilos of weight; your flexibility might have altered from different types of exercises. You might just do miles and miles over winter on the bike and you get to the summer and you need to do different kinds of efforts. You’ll be putting yourself in different positions.”

The fit bike for bike fitters?

Apex can be used as a standalone fitting system or be integrated into another set-up, such as Retül, or added to a simple camera-only studio.

The software that comes with the Apex gives a simple starting point for fits either from existing bike measurements, an easy LeMond-style inside leg formula or an existing set of coordinates. One button and the motors whir into life, setting the dimensions exactly.

Made entirely in the UK, Apex says its system is relatively cheaper for shop owners than the Guru fit system (now owned by Cannondale) or Retül (now invested in by Specialized) with the camera system and Muve bike. Apex have supplied 17 units in total, 15 in the UK and two elsewhere. Time will tell whether more bike shops invest in the system.

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