Welcome to Pedal Science, the weekly bike fitting blog by Nick Thomas of The Endurance Coach. This week we look at the subject of TRI BAR ANGLE and cycling performance.
Once the height, length and width of tribars have been established the angle must be determined to complete the fitting process. There’s a range of positioning available when it comes to tribar angle:
This is where the tribars point down. People often describe better ‘leverage’ in this position.
This tends to be the most common way most people fit tribars.
This is when the tribars point up. Arguably the most efficient angle to position tribars.
There is little aerodynamic advantage to be gained by choosing a declined, horizontal or inclined position for most people – however the position will heavily influence riding speed due to the varying levels of comfort and efficiency provided.
When resting on tribars the aim is to relax and weight bear on them, thereby preventing unnecessary stress developing throughout the back. Very few people we deal with have their tribars fitted at an angle which allows them to fully relax into the bars. This often results in the rider describing an increasingly stiff or painful back which becomes worse the further the ride progresses.
The position we look for is a maximum of 90 degrees at the elbow when riding in the aero position. If the angle is greater than this the person isn’t settling into the bars properly: their body weight is effectively sliding forwards (especially with declined bars) which requires more muscle tension throughout the back muscles and hip extensors to maintain the riding position.
Tribar angle is therefore determined by the correct angle at the elbow which in turn is influenced by the 90 degree angle at the shoulder (see previous article). For most people the upper arms should be angled slightly forwards when riding on tribars which means the forearms should point up to some degree to achieve the maximum 90 degrees angle. This arm position determines the correct tribar angle.
Once the correct angle has been achieved people usually comment how much more comfortable the position is and how much more relaxed their back feels. Both these factors are crucial when establishing the best riding position as aerobic power won’t be maintained if the riding position is inefficient or uncomfortable.
The comparison between the first and second half of an Ironman bike course highlights this point: most people can maintain a poor riding position for 56 miles but as the race progresses there are increasing more people sat up, fidgeting, stretching and unable to maintain their riding position. The result? A slower than expected bike split and further deterioration on the run.
The tribar angle should provide a riding position which enables the rider to weight bear into the bars and minimise unnecessary muscular tension throughout the body. The longer the event the more time will ultimately be lost by fitting the bars at an incorrect angle.
Nick Thomas is the resident bike fitter at The Endurance Coach. He is a fully qualified bike fitter and expert in lower limb mechanics, holding a BSc (Hons) in podiatry. You can contact him using the email address: firstname.lastname@example.org or see more about his fitting services by GOING HERE.