Cycling, Gear, Podcast

Bike Fitting Q&A with Phil Burt | EP#254

 October 5, 2020

By  Mikael Eriksson


Phil Burt2

In this Episode you'll learn about:

  • Crank length - are shorter cranks beneficial?
  • Finding the right balance of comfort, power, and aerodynamics
  • Saddle considerations
  • The process of do-it-yourself bike fitting
  • How to find a really good bike fitter
  • Cleat position
  • Oval chainrings
  • Bike fitting considerations for road bikes, TT bikes and mountainbikes
  • Prevention and remedies for various aches and pains in cycling

Sponsored by:

Precision Hydration

Precision Hydration
One size doesn't fit all when it comes to hydration. Take PH's free Triathlon Sweat Test to get personalised hydration advice tailored to what you're training for. Use the promo code THATTRIATHLONSHOW15 to get your first box for free!

The finest triathlon wetsuits, apparel, equipment, and eyewear on the planet. Trusted by Lucy Charles, Javier Gómez-Noya, Flora Duffy, Mario Mola, and others. Visit for 20% off your order.


Short background

03:45 -

  • My name is Phil Burt and I was the former head physio for British Cycling and Team Sky.

    During this time I did become very interested in aerodynamics since it was such an important parameter in cycling.

    I became specialized in setting up the riders in extremely aggressive aero positions and was also very engaged in constructing very aerodynamic skin suits for racing.

    Nowadays, I have my own business where I perform bike fits.


06:00 -

  • What is the purpose of doing bike fits regularly, let’s say once every year or are you fine by only doing a bike fit once you get a new bike (or change any other kind of major equipment)? What is your recommendation in regards to this?

    I would say that as long as the bike and any other major equipment is the same and your goal (your purpose with the bike) is the same, then I don’t see a purpose of updating your bike fit regularly as long as you’re happy with how you feel on the bike.

    But in case you let’s say have gone from being a ”hobby cyclist” to having performance demands, then you may want to update your bike fit since the first one was made with the intent of prioritizing a comfortable position instead of maximizing performance.
  • When it comes to bike fit of tempo bikes, would you agree that ”going narrow” is the new ”going low”?

    The majority of the people do find it beneficial to go quite narrow with the arms, however, this does not apply for everybody, it’s all about how the wind flows over the body and for some people the wind flow is more efficient when the rider has his or hers arms slightly wider.

    - And what’s your tips for getting narrow without compromising power, breathing possibility and comfort?

    Work on your shoulder mobility, it is crucial to have a certain degree of shoulder mobility in order toileting be able to hold a really narrow position for a long time.
  • When doing a bike fit at home, what should the hierarchy of prioritizing different aspects of the bike fit be?

    When I do a bike fit, I prioritize the following aspects in the given order: aerodynamics, power and comfort/sustainability, however, when doing a bike fit at home I would then switch places between aerodynamics and comfort/sustainability since for people doing bike fits at home comfort/sustainability is the most important aspect plus it is really hard to see and know how aerodynamic something really is.
  • What are your thoughts on cleats and their position on the shoes?

    How the cleats should be place is a whole science and when professional bike fitters do this, they have some really technical stuff for it but really, it all comes down to every athletes instinct, feel and power producing ability.

    If one is going to change shoes or cleats my recommendation is always to try and place the cleats as close as possible to where they sat on the old shoes.
  • What is your thoughts on the praying mantis position (high hands)?

    I think that the reason for why this high hand position has increased in popularity lately is not because it is more aerodynamic per se (even though for some people it is), but for most it makes it easier for the rider to hold his or hers position for a longer time as well as may increase the power producing capacity.
  • Is there a way of finding out what saddle suits you without having to buy them all?

    Some stores do offer ”test and return” of saddles, so that is always something one can check.

    Otherwise, first make sure that your position is correct because you can have the best suited saddle for you but if it isn’t in the right place it would still be uncomfortable.

    I would go to someone who is specialized in saddle discomfort issues and let them do an analysis of your issues.
  • What are your top three do-it-yourself bike fit tips?

    Always make sure your saddle is level or slightly pointed downwards, make sure your saddle is in line with the frame and double tape your handlebars.

    The most common mistakes I see people do is that they sit too low and too far back.

    Finally, have slightly wider tires than you would normally have in the past, it really improves comfort.
  • Is there a way to accurately measure/calculate your saddle height, how do you know when it is correct?

    There is no optimal saddle height but there is an optimum saddle height window, which for some people is really narrow and for some people really large.

    Taking your inner leg measurement and multiply by 0.88 will get you in that window, so it is a good start.

    However, one must be aware that saddle height, saddle position and saddle angle all interacts with each other and hence it is hard to say one specific saddle height is recommended (it is affected of the other two parameters).
  • Should triathletes set up their rad bikes differently compared to the way cyclists set up their road bikes to minimize angle differences in comparison to the TT bike?

    No I wouldn’t say so, the geometry of TT bikes and road bikes are so differently so trying to mimic the position on a TT bike on a road bike would not to be recommended.
  • And should you avoid doing brick runs off your road bikes?

    Yes definitely, that will increase specificity massively to the purpose of brick sessions.
  • What is your thoughts on moving your cleats far back on the shoe?

    I don’t see or know of any negatives with moving the cleats far back, it will probably aid power transformation and may also ”save” the calf muscles slightly (but I haven’t seen any science of that), what I do know, however, is that no power is produced below the knee in cycling since paraolympic athletes have the best power transformation within cycling and that is because it is completely stiff below the knees.

    The most important aspect of moving the cleats back would, however, be to avoid knee injury, which is quite common with athletes with cleats rather far forward.
  • Is there more important to get the bike fit right when you’re supposed to ride an Ironman bike leg compared to a shorter time trial event?

    Yes, I would say the fit would be more important for the longer events since you then need to be much more cautious about the sustainability of the position, which you don’t need to be too worried about for shorter time trial events.
  • I do some of my weekly training sessions on a Watt Bike, how do I best replicate the position on my regular bike with the position on the Watt Bike?

    Take some simple measurements of your settings from your regular bike, typically the distance between the saddle and the bottom bracket and the nose of the saddle to the hoods (as long as you measure from the exact same points between the bikes it doesn’t matter exactly which measurement points that were chosen).

    Interestingly, I have found many people claiming that they produce much more power on the Watt Bike compared to their regular bike, which could have to do with the crank length, which always is 170mm on Watt Bikes (and this could be the reason for the difference in power).
  • What are the principles for choosing the right handlebar width?

    We bike fitters do have plenty of fancy gadgets for measuring this out, however, it is really easy to do by yourself and the procedure is to visualize a line that goes from your hands (starting between the thumb and the index finger) all the way to the shoulders when you are holding the hoods, this line should go straight from the hoods to the middle of the shoulder joint, then you have the right length!

    Most bikes unfortunately come with slightly too wide handlebars.
  • How does mountain bike fitting differ from road bike fitting?

    Massively! And I’m not updated within this particular field.
  • How important is it to get a really good bike fit for a mountain bike with the purpose of racing Xterria triathlon (since during a mountain biking you go a lot out of the saddle and move around a lot on the saddle as well)?

    A good bike fit is always important but it is definitely less important for mountain bikes for the already above stated reasons.

    I am not updated on mountain bike fitting but from what I have understood it is crucial to have a position that enables you to produce power from the knee, which means your saddle shouldn’t be too high or too low.
  • And when buying a new mountain bike, should you first study models that suit you and your position and buy such a bike or could you just buy any mountain bike and then adapt it to your demands?

    Always make sure to buy a bike that you will be able to fit properly on!

  • What is your take on shorter crank arms?

    The science is really clear on that for endurance cycling, the crank length does not matter when it comes to power production (you would have to go really long or really short for crank length to matter).

    The benefits of having a shorter crank length is that it will make it easier to breath, the hip angle will be much more relaxed and the dead spot on top of the pedal cycle will be smaller, so it is all basically just good aspects with shortening your cranks!

    However, it will influence cadence and gearing choice but the body will compensate for that so it does not matter for power production.

    Height also has some influence on crank length (shorter cyclists should have shorter cranks).

    In general, the cycling industry has not caught up with this aspect yet and I would say that most bikes come in too long crank lengths (typically 5mm too long), some brands, however, offer their customers to chose the crank length as they buy the bike.

    I would say that most people could easily ride 5mm shorter cranks than what they are currently doing, however, when changing the cranks one also needs to change the position (raise the saddle height).
  • If you have a road bike with tri bars, should you set it up mostly as a TT bike, a road bike or something in between?

    It’s not ideal to remake a road bike to a TT bike by setting aero bars on it because of the geometry, however, if it is going to be done, I would recommend going very short crank arms and then mostly set it up as a TT bike.
  • My bike fitter and I decided to adapt slowly to a more and more aggressive position (aerodynamic wise), I now feel that I could probably be able to go lower/more aggressive, what is your opinion about the time perspective of adapting to more aggressive/more aero positions.

    I am all about adapting slowly into new positions, however, it all depends on how sensitive you are to changes, some people can handle rather big changes without too much trouble while others are much more sensitive.

    My recommendation would be to lower 10mm at the time and then give yourself plenty of time to adapt to that position, don’t for instance go out for a really long ride the first session with the new position.
  • What is your opinion about oval chain rings?

    The science done on oval chain rings are really inconclusive, however, some people find them beneficial but from a physics standpoint it shouldn’t matter wether your chain ring is oval or circle shaped.
  • When changing saddle height, do you always need to shift the saddle back or forth at the same time?

    Yes, in case you want to maintain the same angle for the legs in regards to the bottom bracket you must do that.
  • Do you think that there is still room for aerodynamic improvements among many triathletes if you would have to take into account that one must be able to run off the bike as well?

    Yes I do, however, many triathletes do have really great positions and in my experience triathletes are much more opened to try new ideas than cyclists, which make them more prone to get into a good aero position.
  • How do you find a really good bike fitter?

    It is really hard to find a good bike fit since this profession is not regulated, but my main advice would be to have a phone call with the bike fitter and discuss what you want to get out of the bike fit and if the answers seem plausible and well thought through, this is probably a good bike fitter.

    Another way could be to take part of testimonials and/or check with local high performance athletes or coaches if they have any certain recommendations.
  • What are the key sizing criteria when buying a bike?

    In most cases the only tools for measuring out what frame size you should go for when buying a new bike works really well, otherwise you can go to a store and test different frame sizes and get a feel for what seems right.
  • How do you minimize hand numbness and are there differences between an optimal climbing position and a ”regular” position?

    First, yes there are significant differences if you are to set up a rider for a climbing only event.

    In order to minimize numbness in the hands I would first check handlebar width, then I would also check the height of the handlebars (if placed too low, then the pressure on the hands is very high), a third tip is to double tape the bars.
  • How do you avoid numbness in the feet?

    Two things lead to numbness in the feet: 1. The shoes are tightened too much (feet tend to swell when they get warm). 2. Non-optimal foot position (normally too much pressure on the forefoot).
  • Is there a difference in setup when between a snub-nose saddle or a regular saddle for road bikes?

    I would say that there is no valid rule for this, however, the benefit with the snub-nose saddles is that you can move the saddle a little bit forward and hence get into a much more aggressive position.
  • What are, in your opinion, the best bike fitting trends at the moment?

    Paying more attention to crank length, prioritizing comfort and sustainability, optimizing the foot position inside the shoes by special soles.
  • Different bike fitters will set you up slightly or highly differently, so how do you know what the optimum position is for you?

    This is a really hard question to answer, and the truth is that your optimum position is different from days to days.

    I read one report that found out that the differences between setups from different bike fitters didn’t vary too much (just slightly).

    In order to get the best position possible, you need to be active yourself during the bike fit process.
  • When I sit on my time trial bike, I am leaning slightly towards the left, however, I don’t see to suffer too much from it but should I still try and break this habit?

    If it doesn’t cause any troubles or problems whatsoever, then I would probably not try and do much about it.
  • How do you find the optimal balance between the most aggressive aero position and not being too stiff for the upcoming run (for Ironman racing)?

    There is basically no way to determine different positions objectively in non-maximum cycling, which makes this question really hard to answer.

    I often go by the rule ”if it feels good, goes good and looks good” then it is probably good.

    One shouldn’t even neglect the mental aspects of thing as well, if one position makes you feel good once you get off the bike, then it is probably worth sacrificing a few watts in aero gains just to be able to go into that run feeling good!


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.

If you are a long-time listener and appreciate the value the podcast brings, please consider taking a couple of minutes for leaving a rating and review on iTunes/Apple Podcasts, or wherever else you can think of leaving a rating and review.

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Explore our products and services