The Most Popular Types of Automotive Wire Harness Tapes

The wire harness tape you choose for wrapping wires on your car or motorcycle is of utmost importance. Your car’s wire harness connects everything from the dashboard to the speaker systems, power steering and turn signals, amongst other things, and with the growing implementation of cameras, charging ports, screens and other electrical elements in the vehicle, secure wiring has become a top priority. Damage to your vehicle’s electric system can be detrimental, leading to a wide range of system failures, or worse – fires. The tape you use to bundle the wires needs to be resistant to extreme temperatures, abrasion from road debris and rock and even chemicals.

The right underbody loom tape will have all of these features, while providing reliable adhesion to any place in the vehicle, no matter whether exposed to the elements or cramped between multiple parts. The most popular type of underbody loom tape used to be PVC. The reasons for that are its flexibility. Nowadays, there are more choices than ever, and no matter which one you go for, you need to consider its properties. Here are the properties that matter most.

Abrasion Resistance

Automotive tapes are rated A-F depending on how resistant they are to abrasion. A means the tape has no resistance, and F means the tape is very resistant. The ratings are based on the ISO 6722 standard, where an abrading tool is rubbed back and forth across the tape under pre-specified conditions and pressure. A-rated tapes won’t survive more than a few hundred strokes, whereas F-rated tapes will survive up to 15.000 strokes.

wrapping wires with underbody loom tape

Cloth polyester has become a very popular type of tape recently, due to its outstanding abrasion and heat resistant properties. It’s also easy to tear by hand and flexible, making it easy to apply. If the polyester is non-woven, it’s also very good for sound attenuation. That being said, modern textiles are tougher than before, which is why tape manufacturers are slowly moving away from PVC tapes.

Heat and Electrical Insulation

These two areas are where PVC tape excels. PVC is a great electrical insulator, however, the high temperatures around the engine have forced tape manufacturers to consider other tape options, such as vinyl, foil, fleece and polyester. Glass cloth tapes, for instance, have much better heat-resistant properties compared to other textile tapes. The tape backing isn’t the only thing that impacts insulation and heat resistance, though. You also need to consider the adhesive layer, which must survive great temperature fluctuations without peeling, and it must also help insulate the wires to which it’s adhered.

Contaminant and Chemical Resistance

Woven tapes excel in areas where contaminants and oils are present, especially if treated or laminated. However, foils and polymers provide a more secure seal. The majority of polymers, like PVC and polyester, can withstand corrosive substances and protect your vehicle’s electrical wires from any damage. Cloth tape, on the other hand, needs to be coated in order to have the waterproof, flame-retardant and chemical-repellant properties needed for use in the automotive industry.

cloth tape

The ideal wire harness tape for your vehicle will depend on where you want to use it. The adhesive layers and backing you choose will depend on the threats present at that location. It’s best you consult with a supplier of automotive tape so that you get a better understanding of the specifics of the tape application.

How to Apply the Tape

Generally, this is a very intuitive process. But you need to consider a few factors before doing so. Usually, tapes will feature an adhesive backing on one side. In some cases, the adhesive will be exposed as you unwind the roll, whereas other tapes will feature a paper-release liner to prevent the adhesive from sticking to the roll material. There are also tapes that don’t use an adhesive whatsoever. Self-vulcanising and friction tape are two such tapes. In most cases, the adhesive is applied with the adhesive side facing the wires or cables. If the material features a paper-release liner, make sure you remove it just as you apply the tape around the wires.

In most cases, you should wind the tape in a helical manner, winding the first tape at a 75° angle. Each wind of tape around the wire circumference should slightly overlap the previous wind by about 50°. Polymer film tapes are somewhat elastic, making it easier to wind the tape and ensuring a smoother, more uniform look by minimising wrinkles. However, stretching the tape more than you should, can make the tape narrower in width and force individual coils to pull back and expose parts of the adhesive over time. That being said, avoid overstretching unreinforced film tapes. On the other hand, metal foil and woven fabric tapes don’t have much elasticity, and you need to get the starting angle right in order to get a smooth and uniform look that’s free of wrinkles.