Croston Cycles Bike Fitting Blog - How wide should your aero-bars be?

Croston Cycles Bike Fitting Blog - How wide should your aero-bars be?

The previous blog discussed how to establish handlebar width and the consequences of riding with incorrectly sized bars. Similar consideration should be given when fitting aero-bars as any aerodynamic advantage can easily be negated by an inefficient riding position. In recent years, the development of aerodynamic positions has been prominent in time trial and triathlon. One of the biggest issues we see is that the aerodynamic position is often created on an indoor turbo trainer where the rider is required to hold it for no matter than a few minutes. It creates a great looking photo for social media, but in the real world, the rider isn't able to hold that position for any significant period of time. 

Aero-bars are fitted to increase speed but this can only be achieved if both the following points are realised:

  • The rider reduces frontal drag and achieves a more aerodynamic riding position
  • Power is equal to or higher than riding without the aero-bars
  • The rider can maintain the position without being in discomfort
  • The rider can safely steer and control the bike

When establishing aero-bar width there are three main consequences when fitted too narrow:

  • Breathing can be restricted if the chest isn’t able to fully expand – this will be more apparent during shorter, faster events where there is greater oxygen consumption and the chest expands more
  • Shoulders become rounded which can lead to excessive tension across the upper back and shoulders, as well as the lower back. 
  • Steering can become very 'twitchy'. 

Although less common it’s also possible for aero-bars to be too wide. This can be more comfortable and stable but aerodynamics are compromised. If the aero-bars are achieving a less aerodynamic position, then the wisdom of fitting them in the first place needs to be questioned.

Aero-bar width is relatively easy to establish with most people. When viewed from the frontthe elbows should be positioned slightly inside the shoulders with the hands slightly inside the elbows. A simple test to assess the correct width is as follows:

  • Stand with your arms pointing directly in front of you horizontally
  • Bend the elbows to 90 degree so the forearms are positioned vertically
  • Slowly bring the forearms together across your chest in front of you (keeping them vertical)
  • Stop when you feel tension across the shoulders developing
  • The position of your forearms at this point is about as wide as the aero-bars should be

When buying aero-bars ensure they provide a good range of adjustability in terms of bar reach and arm pad width. Bars which prevent you from achieving your ideal position are not fit for purpose.


It’s possible to achieve an aerodynamic position without compromising comfort, breathing or stability. By performing a simple test you can achieve a riding position which optimises aerodynamics and enables you to ride to your physical potential. Don't be drawn in by the social media photos, whilst some positions may look incredible, for most people, they're simply not practical. 

Nick Thomas is the resident bike fitter at The Endurance Coach, based at Croston Cycles. He is a fully qualified bike fitter and expert in lower limb mechanics, holding a BSc (Hons) in podiatry. A 90 minute bike fitting session costs £75 and you can contact him using the email address: or see more about his fitting services by GOING HERE