Cycling, Gear, Podcast

Bike fitting with Phil Burt (former Team Sky) | EP#232

 May 4, 2020

By  Mikael Eriksson



In this Episode you'll learn about:

  • Physiotherapy, injury prevention, and bike fitting
  • The balance between aerodynamics, power production, and comfort
  • How to adapt to a new position on the bike
  • How to optimise aerodynamics through bike fitting
  • Saddles and saddle health

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04:40 - 

  • I was the head of physiology for British cycling between 2006 and 2018 and helped set up Team Sky.

    In recent times, I have set up my own company, which is offering bike fitting services (from amateurs to professional, including the British national triathlon team), is involved in innovations of different kind.

    My background is as a physiotherapist but nowadays I would rather call myself an ergonomist, I study the integration between ”humans and machines”.

    I have also wrote two books, one on the topic of bike fitting and one that is called ”how to get better on the bike off the bike”.

The connection between physiotherapy and bike fitting

08:52 -

  • I think that bike fitters with some kind of ”medical” background, such as for instance physiotherapists, tend to be somewhat more successful compared to those who are following more of a standardized bike fitting procedure.
  • My bike fitting philosophy is that ”the bike is adjustable and the rider is adaptable”.
  • Every bike fit is unique since every human is unique and has unique goals, and this is an important reason for why it is highly beneficial for someone that has an understanding of the human body to carry out the bike fit as this makes it possible for the bike fitter to adapt the fit to the athlete in front of his or her and not just following a strict procedure.

The most common bike fitting mistakes

12:12 -

  • In general, injuries are relatively rare within cycling compared to for instance running, however, some common injuries do occur.
  • The most frequently occurring injuries in cycling are knee-, shoulders- and back related injuries.
  • The knee joint is the one joint that is basically taking all the load when cycling, which if the rider is sitting correctly can help strengthening the knee but can also lead to knee discomfort if the rider does not have an optimal knee angle.

    I usually see people sitting a little bit too low and far back (when riding a road bike, does not apply to the same extent for the time trial position), which can lead to knee issues, and hence I use to move athletes a bit up and forward on the bike.
  • Shoulder injuries are also very common within cycling, which for one reason is because the shoulders and collarbone normally take the main hit when crashing, but another common reason for shoulder and neck discomfort is too low and too wide handlebars.
  • The back is the third structure that is quite injury prone in cycling, which in most cases is because many riders let the spine stand for the entire bend of the upper body, which since you sit with a bend back for a long time leads to stiffness.

    The way of getting away from this is to make sure that the pelvis is angled forward so that it also contributes to the overall bend of the upper body.

    This can be achieved by tilting the saddle a few degrees downwards, which helps the pelvis to rotate a bit forward and hence take away some of the bend from the back.

    Tilting the saddle forward or having it completely flat is something every rider can experiment with on their own and find out hat works best for you.

The bike fit process

20:20 -

  • According to me, there is no optimal bike fit, there is instead a ”bike fit window” in which the rider will be able to put out good power and at the same time be really comfortable, this could for instance be: ”the saddle height should not be lower than this or higher than that”.

    Some riders are extremely sensitive to small changes in the bike fit compared to other people who may not even recognize them.
  • There are three major pilars that I consider to be the most important when carrying out bike fits, these are: aerodynamic, comfort and power.

    When performance is the main goal, then aerodynamic and power is the most important factors to consider, however, if the athlete’s event is an Ironman bike leg, then there has to be a high degree of sustainability and comfort in the position.

    On the other hand, if the athlete is cycling predominantly for recreational purposes, then comfort would be the major pilar to consider.
  • Another aspect to consider in the bike fit process is how adaptable the athlete is, an older athlete is generally not as adaptable as a younger athlete (for instance a 16 year old who has not yet reached full length), and in the latter scenario, it might be a high priority to try and adapt the rider to a more optimal position from a performance standpoint.
  • When it comes to adapting to a new position, this takes time for most people and should be carried out in smaller steps in order to find how far you are able to take things.

    When it comes to aerodynamic for instance, the most common tweak to improve the CdA is to go lower in front.

    This particular change can take some time to adjust to and hence, the process should be carried out in steps where you lower your pads a few millimiters every week or until you feel you have adapted well to the new lower position.

    When it comes to saddle height and crank length, however, those changes normally does not need to be carried out in small steps.

Crank length

30:35 -

  • Firstly, what one must understand is that crank length does not affect the ability to produce power, unless we are talking about ridiculous extremes.
  • What happens when crank length is reduced is that the hip angle is getting more opened up and the knee doesn’t ”bump” into the stomach as much, which makes it easier to breath and also makes it more accessible to getting even lower and more aerodynamic.

    So, for me going with shorter cranks is a benefit in almost all situations, and could as well help for those with knee injuries.

Power production and aerodynamics - how much of a give and take?

34:25 -

  • In my experience it is very much a give and take relationship between these parameters, getting more aero generally makes you less powerful and vice versa.

    However, there are some tweaks you can do to both become more powerful and aerodynamic at the same time, this is for instance, as I was talking about previously, moving the saddle up and forwards, which leads to a more aggressive position.
  • My philosophy is that the first priority is to get the ”engine” right, which is the saddle height and position as well as crank length, so that the conditions for producing power are the best, since you have to be able to pedal hard to go fast.

    From this position, you can then start manipulating the front end by getting lower, narrower etc. in order to improve aerodynamics, but this shall be done in a later stage.

    What’s important to consider is that the bike represents only 10-12 % of the total frontal area, while yourself stand for the remaining part, so for this reason, picking the right skin suit is very important and this is where you should spend most of your money in order to improve aerodynamics.
  • Another key part for aerodynamics is actually the saddle as a comfortable saddle helps you to stay in the aero position as well as it helps you rotate your pelvis forward, which gets you more aggressive on the bike.

Saddle choice

38:00 -

  • This is an extremely large subject, which of course is highly individual and therefore a little bit hard to talk about remotely.
  • However, there are a few things one can consider when it comes to saddles, which are: width (there are typically three different widths and generally women tend to need somewhat wider saddle), shape and length.
  • Example of saddles that works really well for plenty of people is the split nose ISM, the Specialized Mimic (has a soft nose) and the new Gebiomized saddle.

    However, I think that all the major brands like Fizik and Sella Italia have some really good saddles, and no brand is generally better than the other, you just need to find what works with you.

    I would also like to point out that spending more money on a saddle doesn’t necessary guarantee better comfort, price has more to do with weight.
  • Finally, I must also say that it doesn’t matter what saddle you have, unless you don’t sit optimally on the bike, no saddle out there will be comfortable to sit on.

Bike choice

45:00 -

  • Generally, almost anyone can fit on any bike brand as long as the size of the bike is the right since the adjustability options are so vast.

    However, the geometry between different brands can vary slightly, which might be worth considering if your body composition is rather far away from the normal distribution, like if you have really long legs and short torso or vice versa.

    But I would still say that if you make sure to have the parts (crank length, ideal cockpit settings, right stem length etc.) are optimal, then there are very few people that cannot be fitted properly on pretty much any bike.


47:40 -

  • Helmet choice is very important, one can see major improvements in aerodynamics when finding a helmet that fits the athlete’s profile very well.
  • Once again saddle choice, a saddle that helps you rotate your pelvis forward and hence gets you more aggressive on the bike, which is highly beneficial in regards to aerodynamics.
  • Then I would work as much as possible with oneself, getting more flexible in the hamstrings, lats, thoracic spine and neck, then you will be able to time trial better and longer.

    Both Yoga, Pilates or physiotherapy can be beneficial in order to achieve this.
  • When it comes to measure and validate aerodynamics, this is actually much, much harder and more time consuming than many ”experts” and companies claim.

    During one day in the wind tunnel, one can for instance only really assess two to three different positions.
  • In order to be able to really assess potential gains in aerodynamics, one must be extremely methodological about it, and many cycling pro teams does not even do this in a very professional way.


58:35 -

  • The technical devices that I regularly use are the following: Retül fit system, Gebiomized saddle pressure system and of course video.
  • Everyone that does a bike fit with also get a personal ”plan”.

How to find a good bike fit

1:04:50 -

  • In regards to what to look for in a bike fitter, it can be really hard to get an idea how good this particular fitter is.

    My most important tip would be to call the person you are planning to see and from that you for most of the time get a really good idea of wether this is a person that you would trust performing your bike fit or not.

Rapid fire questions

1:01:10 -

  • What is your favorite, book, blog or resource related to cycling or endurance sports? My favorite book is Supple Leopard by Kelly Starrett, anyone wishing to get more flexible has a lot to learn from him, and his online stuff is really useful too.
  • What is your favorite piece of gear or equipment? My bike, which is from a local store but I also ride Specialized.
  • What is a personal habit that has helped you achieve success? I would like to know everything before I make a decision, which makes me really do the research properly.


Mikael Eriksson

I am a full-time triathlon coach, founder of Scientific Triathlon, and host of the top-rated podcast That Triathlon Show. I am from Finland but live in Lisbon, Portugal.

Please contact me if you have feedback on the podcast or want to make suggestions for improvement or send in a question for a Q&A episode.

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