Bike Science Aero Bike Fitting - What to Expect

The Bike Science Level 2 Aero bike fitting is proving to be our most popular appointment this off season, but what should you expect when visiting for this three and a half hour session and what will you gain from the process?

Meet your Fitter...

Bike Science founder and head fitter Andy Sexton performs all bike fits in our South West bike fitting studio at his home in Dursley, Gloucestershire. Andy has been cycling for thirty five years, competed in triathlons up to Ironman distance for twenty years and has been a professional bike fitter for fourteen years having fitted over ten thousand riders during this time. He has a wealth of experience in helping riders from complete beginner to professional and now also teaches bike fitting courses.

Who is the Level 2 Aero Bike Fitting Suitable for?

The Level 2 Aero Bike Fit session is aimed at relatively experienced triathletes or time trial riders who ride in the aero position using tri bars. It is applicable to riders covering any race distance.

What is the aim of the session?

The aim of the aero bike fitting session is to help the rider develop a position on their bike that offers a suitable, sustainable blend of comfort, power and low aerodynamic drag. The session also helps the rider see the effects that their own body position and posture has on drag and helps them practice developing a posture that offers the lowest aerodynamic resistance.

What Technology is Used During the Session?

A combination of tools are used in assisting the fitter in making informed decisions about rider positioning and aerodynamics.

The Retül motion capture system is used to measure and record rider movement. BioRacer Aero Virtual wind tunnel software uses a high resolution camera to asses the rider's frontal area and infer aerodynamic drag data.

In cases where a rider muscular imbalance is suspected a technique called surface electromyography (sEMG) can be used to study the muscular recruitment of any chosen muscle group while pedalling.

A Wahoo Kick turbo trainer is used during the session to allow accurate measurement and control of power output whilst rider measurement takes place.

The utilisation of these high-tech methods for rider assessment gives a high level of confidence when judging the overall best compromise for a given rider between comfort, power and aerodynamics.

BioRacer Aero camera frontal area assessment.
(29W Saving equates to approx 13mins28s improvement over Ironman 112 mile bike leg)

What is the Process?

The fitting session starts with a pre-fit questionnaire which we ask you to complete before your visit. The questionnaire gives our fitter an idea of your experience level, riding aspirations, injury history and any discomfort issues you may be experiencing prior to your arrival.

Once you arrive, your bike will be set up on the Kickr trainer and you'll be given the opportunity to warm up whilst discussing your riding and any problems you may be experiencing further.

Once the warm up is complete, a detailed off the bike assessment of rider flexibility, strength, stability and symmetry takes place.

At this point you may be offered (if beneficial) a pair of Sidas custom cycling footbeds. These are available at half their usual retail price during any fitting session. Custom cycling footbeds are moulded to the contours of the riders foot in order to support them in proper alignment and spread pedalling loads evenly across the surface of the foot.

Our fitter will then use the Retül motion capture system to dynamically measure your movement whilst riding at a know and controlled power output. The bike, shoes and cleats will then undergo a series of adjustments with measurements being repeated to assess changes to rider motion along the way. This stage of the fit offers the rider an opportunity to try a wide range of saddles if required. The aim is to determine a range of positions that can be tested during the "aero" phase of the fit to find which offers the best compromise between comfort, aerodynamics and power production.

The "aero" stage of the fit then utilises the BioRacer Aero virtual wind tunnel software to study the effects on rider frontal area (and drag) of changes to tri bar height, width and tilt (within the ranges determined in the first stage of the fitting). Drag data is projected onto a screen that can easily be seen by the rider so they can see the effect on drag of any changes made.

Once the fitting process is complete an accurate measurement of bike set up is made and recorded. These measurements can then be used to help guide any future bike purchases or fits.

What Can I Expect to Gain?

The end result of the fitting process is a riding position that is appropriate to your chosen event and riding aspirations while taking into account any former injuries. Actual on road gains in speed can be hard to assess accurately, but improvements in power output requirements to hold a speed of 40km/h of between 10 and 50 Watts are not unusual.

What Should I Bring?

Please bring the following items to your Level 2 Aero bike fitting...


Cycling Shoes


Tri Suit, Skin Suit or Bib Shorts with Vest top

Any tri bar risers/spacers and associated bolts needed to make front end height adjustments

Any other spares required to adjust bar position and saddle position on your particular bike

Aero helmet if you own one, otherwise your standard road helmet.

Got Questions?

Feel free to email Andy with any specific questions

Booking and Pricing?

The standard price for a Level 2 Aero Fitting (as of original publishing date of this article Nov 2019) is £199.99. A session lasts 3 1/2 hours.

Pre-Christmas Offer 2019 - All Level 2 and Level 2 Aero bookings until Dec 24th 2019 are subject to our pre-Christmas fitting offer.

Level 2 Fit - Off Peak (was £149.99) - Offer £100

Level 2 Fit - Peak Time (was £184.99) - Offer £125

Level 2 Aero Fit - (was £199.99) - Offer £135


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