UCI banned road bike position aerodynamics

We tested 6 positions in total that might be used in racing when travelling at relatively high speeds (on the flat, not whilst climbing). 

RELAXED ARMS HOODS (baseline)

The baseline and reference position was holding the hoods, with slightly bent elbows. This is a typical comfortable position that can be held for long distances.

DROPS

Holding the drops helps reduce torso angle, which is often more aerodynamic on a road bike, and is useful to lower the centre of gravity when cornering or descending.

AERO HOODS

This is similar to the hoods position but with forearms parallel to the ground. Popular for breakaway riding it helps to lower your torso angle and also present less forearm to the wind compared with the drops position.

FOREARM RIDING (banned)

This simulates an aerobars position by resting the forearms on the tops of the bars, with hands draped over the centre of the bars in mid air. Resulting in less control, it was a popular position for breakaway riders or those at the front of the peloton. This has been explicitly banned by the UCI since April 2021.

LEVER HOOKS (banned)

In order to move the elbows further forward and reduce torso angle, some riders have tried wrapping their hands around the front of the brake levers. This position has caused some DSQs in UCI events since the rule changes in April 2021 so appears also not to be permitted.

AERO HOODS BENT INWARDS

A final position is holding forearms parallel like the aero hoods position, but with the shift levers bent inwards to narrow the hands. There is a risk of elbows flaring out with this position because of the new lever angle, especially when relaxing the arms.

In order to test aerodynamic drag we went to an outdoor velodrome, and our test rider Richard performed a series of repeats of each position using a power meter, whilst we also measured environmental variables such as wind and air density.

Richard was wearing a jersey with bibs, aero socks, an aero road helmet and was on a Giant Propel bike. 

The data was then processed as in our commercial outdoor aero sessions, using custom scripts to establish a CdA (aerodynamic drag) for each position.

CdA is the combination of both frontal area (the A part of the equation) and drag coefficient (Cd), and is reported in m².

The CdAs for each of the positions tested can be seen below.

The banned positions are similar to an aero hoods position, with a slight advantage to the forearm position. Holding the aero hoods position can be quite fatiguing on the upper arms, so making it worthwhile is very dependent on ensuring you can hold it for extended periods. If you fatigue and start to straighten your arms it is then a lot slower.

The bent inwards lever position is faster than not bending the levers in, but with the caveat that it can cause your elbows to flare out when you sit up, which is slower.

Compared with some of the UCI banned positions, an aero hoods position is nearly as fast and much safer. It is much faster to hold an aero hoods position than drops or relaxed hoods, but can be fatiguing and often requires practice.

Bending the levers inwards results in a small improvement. Using narrower handlebars rather than bending the levers inwards will help reduce the risk of your elbows flaring outwards, which will be slower when holding a relaxed hoods position.

The 35w boost by moving to an aero hoods position from a relaxed hoods position at 45kph will increase speed in this example by 1.65kph for the same power output, which is worth  nearly 2min over 40km.