The majority of backyards trampolines are freestanding, i.e. sitting on grass, a rubber mat or a patio surface. The basic parts of a trampoline are the frame, the bed or jumping surface, the springs, and the safety pad covering the springs or “spring pad”. Below is an explanation of each of these elements:

Fig. 1 A typical trampoline frame

Frame
The frame consists of a top rail, horizontal legs, and vertical legs
(See Fig. 1). In general, the fewer frame sections the better. Frame
tubing should be heavy gauge with thick walls and painted or plated for
corrosion protection. Cheaper frames will begin to wobble and twist
over time.

Fig. 2 Spring placement and connection points

Springs
Springs come in a couple of different forms. Most are steel extension
springs with lengths that vary from about 5” to 10” in length, measured
when the spring is relaxed and without tension (see Fig. 2). The
longer the springs, the better the performance. Other trampolines use
elastic straps or fiberglass rods.

Bed or Jumping Surface
The bed or jumping surface consists of a woven polypropylene fabric
bordered by webbing and v-rings or other spring connections. A key
element of the bed is how the fabric feels on a person’s feet and the
quality of the parts sewn onto the mat. Most mat fabric is produced in
the US and is described as calendared, meaning it’s rolled while hot,
which produces a smooth finish which feels much better to jump on with
your bare feet. Also, the more rows of stitching on the edge is
generally preferrable. It is important to have some structural rows of
stitching protected from the sun. This is achieved by adding a sun
guard (webbing strap) over some number of rows of stitching.

Spring Pads
The spring pad protects the jumper from hitting the frame or stepping
or falling through the springs. The spring pad consists of a foam core
with a fabric cover with attachment straps or bungees. Pads are often
sewn (See Fig. 3). Some pads are one piece and fit around the entire
mat and attach to the frame in several locations. Other pads are
segmented and attach together with ties or Velcro. What to look for:
pad thickness, feel and color of the pad fabric, density or firmness of
the foam that is inside the pad, and how the pad is attached to the
frame. The better pads will be an inch thick and made of a firm, high
density foam. The sun is very destructive so it is important to choose
a pad enclosed in a high quality fabric containing some type of UV
blocker.

You are almost ready to call a trampoline sale or service support
representative! First, please take a few moments to read about
trampoline safety enclosures which are a necessary safety device for
your backyard trampoline. You can also read our related article which
describes different styles of safety enclosures.

Happy jumping!