The manufacturer's specifications for the correct pressure in the board are predominantly between 14 and 17 psi. 15 psi is the most commonly quoted standard value. As a reminder: psi is the abbreviation for pound per square inch, and 15 psi is roughly equivalent to one bar - a car tyre usually has a pressure of around 2.5 bar. Up to around 10 psi, inflating the boards is usually still easy, but from 12 or 13 psi at the latest, even trained, heavy paddlers will find it difficult at the very least, and light paddlers will often find it almost impossible or very difficult to manage.
We therefore tested - last summer - with two identical JP Sportsair 12'6'' x 30'' SE 3DS to see whether you can ride quite well with less pressure: With the solid, high-quality SUPs, we were able to reduce the pressure down to 11 psi without feeling any difference for the test subjects (60 and 82 kilos) at normal touring speeds of just under six kilometres per hour. Under the heels, however, the board felt noticeably softer at 11 psi. With our test subject weighing only 60 kilos, there was no difference at all in the water position and the perceived effort at identical touring speed remained the same, as did the top speed achieved. Under the 82kg tester, the board bent slightly visibly, but even at a fast touring speed there was no noticeable difference, only at racing speed - as in sprinting - did the board no longer lie as straight in the water as at 15 psi, bending more, pushing a little more water in front of it and also achieving a - slightly - lower top speed.
Unfortunately, you often see boards that plough through the water in a banana shape, with tail and bow in the air and the paddler's feet almost in the water. In very few cases is this due to incorrect pressure, but usually particularly cheap and above all particularly thin boards plough through the water in such an unsightly way. A board that is only four inches thick is always significantly less stiff than one that is six inches (15.2 centimetres) thick. All the options tested here relate exclusively to solid six-inch boards.
Especially for lighter people, our conclusion is: just try it out without obligation with 13 psi or even with just 12. It costs nothing. Maybe you won't notice much difference either.
We carried out a similar test last summer with GPS speed measurement and recently added another ten extra kilos to the board. Our assessment: At 85 to 90 kilos and more, we would stick to the manufacturer's recommendations, at 80 kilos or less, even two psi less are almost imperceptible or hardly noticeable - as long as you are not paddling in a race. For paddlers of 60 kilos or less, the pumping work for the last two psi seems like a waste of energy. Just test it yourself, you can always pump up again.
