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The average effective seat tube angle of touring bikes is 73.4°. Thus, it’s neither steep nor extremely slack.

By keeping the seat tube angle conservative and balanced, touring bikes offer a mix of comfort and efficiency making it easier to cover long distances as quickly as possible when carrying a lot of cargo.

Let’s start with the definition of effective seat tube angle:

The effective seat tube angle (ESTA) is the angle between a horizontal line (parallel to the ground) running through the bottom bracket and a line passing through the bottom bracket and the middle of the junction where the seat meets the seat post. (image below)

The table beneath contains the seat tube angles of popular touring bikes.

Note: The seat tube angle depends on frame size. The table focuses on medium size frames.

Conclusion: The average seat tube angle of touring bikes is about 73.4°.

This is a fairly conservative value that is neither extremely steep nor radically slack. In fact, it’s similar to what we see on most road bikes these days, especially among the lightweight models designed for climbing.

It’s also necessary to clarify that the saddle setback directly affects a bicycle’s effective seat tube angle.

Thus, in some cases, a touring bike can have a steeper or a slacker effective seat tube angle due to the rider’s specific seat position.

(The height of the saddle affects the effective seat tube angle too – the higher the saddle is, the slacker the effective seat tube angle gets.)

Why Don’t Touring Bikes Have a Slacker or a Steeper Seat Tube Angle?

The conservative ESTAs of touring bikes may come as a surprise to some, but as always, there’s a strong logic behind the chosen bicycle engineering.

The reasons to go with an ESTA that isn’t too steep are:

A very steep seat tube angle combined with the saddle-to-handlebars drop on most touring bikes will result in a very open hip angle (the angle between the torso and the femur).

The open hip angle has two downsides. First, it places more stress on the knees while reducing the input from the glutes. Second, it’s less aerodynamic because the rider is more upright.

Of course, touring bikes are not meant to offer the most aero position, but still, excessive drag is not considered helpful as its effect accumulates over time and limits how much distance the rider can cover in a set period of time.

Another negative side of an excessively steep ESTA is the weight shift to the front. In general, a shift to the front wheel is not a problem in and of itself because it increases front-wheel traction and makes climbing easier.

However, the forward shift places more stress on the wrists, elbows, and shoulders – joints that already take a beating from the prolonged ride. (Hence the need for handlebars with various hand positions).

The reasons to go with an ESTA that isn’t too slack are:

• Smaller hip angle (stretched position)

A very slack effective seat tube angle will close the hip angle and put the rider’s back in a more vertical position. Technically, this isn’t bad in and of itself, but the position could be difficult to maintain given that touring bikes are designed for long-distance riding in changing conditions.

A slacker effective seat tube angle will increase the effective top tube too. As a result, the rider will feel more stretched. This issue can be fixed by using a shorter stem.

Ultimately, touring cyclists aren’t racing. Thus, they care more about comfort than speed. A more conservative ESTA keeps the back in a more neutral position that’s easier to maintain for hours.

• More weight on the rear wheel

If the seat tube angle is too slack, extra weight will be placed on the rear wheel which may already be “suffocated” from a rear rack, panniers, saddle bags…etc. The more weight there is on the rear wheel, the harder it is to spin it.

The loss of front-wheel traction hurts climbing too.

Summary: What You Need To Know

• The average effective seat tube angle of medium-sized touring bikes is 73.4°. This number is neither steep nor slack – just somewhere in the middle.

• The goal of touring bikes is to offer aerodynamics, efficient pedaling, and comfort – all while transporting a lot of cargo in bags and panniers. Therefore, it makes sense to avoid extremes.

• If the angle is notably steep, as it is in the case of tri bikes, the rider may experience knee pain and overall discomfort.

• If the angle is notably slack, the rider may experience back pain and will have to spin a “heavy rear wheel”. The bike’s climbing abilities and comfort will therefore suffer.