Bike-fit has come a long way
Once upon a time you set your saddle height so your leg was straight when your heel was on the pedal at 6 o’clock, tightened up the bolt and off you rode.
Then, ten years ago, Phil Burt wrote a book that changed everything: Bike Fit. In it, Burt detailed how to tailor bike setup not by rules of thumb but tuned to the individual’s needs, drawing on his experience as a physiotherapist working with Team GB and Team Sky.
But a lot can change in a decade, so this year Burt released a revised edition.
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‘I’ve learned a lot more since I wrote my first book in 2012 [published in 2014] and the second edition reflects that, but also it reflects how the industry has changed and evolved,’ Burt says.
‘Since 2018 I’ve been working with mere mortals, and it is a very different game compared to the competitive international scene I was previously in. I’ve also been working on both sides of the camp, on the bike-fit side but also on developing products, so I have a lot more experience to draw from.’
What have been the biggest changes?
Credit: Phil Burt
‘I think the bike industry now listens to the consumer more, and there are now many more options for achieving your goals on the bike – for example the whole gravel scene, or more comfortable positions,’ says Burt, alluding to the widespread appetite for comfort over more ‘pro’-looking setups.
‘Geometry is also changing. Back in the day most high-end bikes were really just for pros, and if you could get on one and hold that position, great. But now there is a clearer focus on what normal people want, which is usually a more relaxed, easy position.
‘I think there is also more understanding about different riders’ goals. For example, if Mark Cavendish comes in and says, “I want to be World Champion again,” his position is going to be very aggressive and powerful, but quite uncomfortable to hold.
‘Whereas if someone wants to do Land’s End to John o’ Groats, it will be a totally different position.’
Has indoor cycling made a difference?
‘This has been the biggest change, because ten years ago we didn’t have the likes of Zwift so it wasn’t a consideration,’ says Burt, explaining that the exponential growth of indoor training has had a major impact on the bike-fit industry.
‘I get asked a lot about whether someone should change their indoor position compared to their outdoor one, but it is a difficult one to answer as it depends on the specificity of training and transfer.
‘The biggest thing I would say about indoor cycling is that because of the sustained saddle pressure, heat and sweat, a lot of people get saddle sores. You haven’t got those natural breaks of getting out of the saddle because of a little hill.
‘Instead, people get fully into the screen and this can create issues. My advice is to set an alarm and stand up every ten minutes – literally for just ten seconds – and this will break up that sustained pressure.
‘Another key consideration is your indoor environment because pressure, friction, heat and water together all lead to skin breakdown. In my opinion you should always have some airflow, like a fan, when cycling indoors.’
How has the growth of women’s cycling changed things?
Credit: Phil Burt
Over the past ten years women’s cycling has become increasingly popular and it is an area where Burt has focussed a lot of his research. He successfully argued for a UCI rule change on saddle tilt, which until 2015 decreed saddles could only tilt by 2.5°, but now the rules permit up to 9° of tilt.
Burt says this was driven by his work with women athletes, and although it sounds like a relatively minor change it helped achieve a 100% reduction in female saddle injuries within the Team GB cycling squad in the run up to the 2016 Olympics.
‘If I look back at the first book, to be honest it’s quite embarrassing how short the saddle section is. I was scared to write about saddles because it is such a minefield of an area. But now I’m out in the real world I can be more honest about it, and one major thing to note is that until very recently, saddles just weren’t designed for women.
‘Women had to find solutions themselves, while men were getting all the designers’ help,’ he adds. ‘For instance, saddles that had a gap were designed for men to help with numbness issues.
‘Some women would find these saddles comfortable while others would not, because women have about nine different presentations of genitalia, whereas men only really have the one, and that makes women’s needs much more complex.
‘In the past women have been so poorly served by the bike industry, but they’re finally starting to be listened to because companies recognise that they represent a significant chunk of the people who will cycle. But it could still be a lot better.’
How are our component choices different (or rather, how should they be)?
One of Burt’s most controversial ideas is that we should adopt shorter crank lengths, arguing that this won’t impede power, but how does this work?
‘We’re all brought up to believe that the taller you are, the longer crank length you need. This is because the longer crank will give you more leverage and therefore more torque,’ Burt explains.
‘But that isn’t actually true in submaximal cycling – the kind of cycling we spend most of our time doing, where we’re riding well below our maximum effort. What that means is crank length is really just a part of your gearing, so you can change your crank length to achieve a better fit without it affecting your performance.’
However, it’s not quite as simple as just using a shorter crank.
‘You have to be clever about it. For example, if I change your crank length from 170mm down to 165mm, the biggest question is what do you do with saddle height? Well, I always say we want to maintain the power so we put the saddle height up and open the hip up at the top of the pedal cycle.’
Burt points out that if crank length doesn’t affect your performance, ‘why would you ride a bigger circle?’ He goes on to explain longer cranks ‘create more kinematic loading of the knee’, which is unnecessary and can lead to fatigue and even injury.
‘Shorter cranks means pedalling becomes easier, in a sense. That’s why I’ve had great success in manipulating crank length around people’s knee, hip and lower back issues.’
It’s also something that Burt sees as having been proven at the highest level too. ‘Bradley Wiggins came to me riding 177.5mm or 180mm length cranks, but for the Rio Olympics we had him down at 165mm for the team pursuit, and he won gold. Then he was on 170mm for his Hour record.’
