TECH TIPS

Tires and Tire Quality

Mobile elevating work platforms (MEWPs) will typically use 3 to 4 types of tires: moulded, pneumatic, foam filled, or solid.

Moulded tires are usually solid rubber tires that are moulded onto a steel rim. These tires are available in smooth or treaded surfaces and black or non-marking designs. Moulded tires are most commonly found on slab scissor lifts.

Pneumatic tires are tires that are filled with air. Pneumatic tires are available in many different designs and tread patterns, and can be standard or non-marking. Tread patterns vary from a chevron style, to turf/high flotation, to highway (automotive) designs. Be sure to check with the equipment manufacturer, as sidewall strength, dimensions, and other dimensions are critical for the stability of the equipment. Pneumatic tires are most commonly found on rough terrain scissor lift and boom lifts.

Foam filled tires are, for the most part, pneumatic tires that are filled with a two-part liquid urethane that is pumped into the valve stem, replacing all of the air. It cures into a solid elastomer and prevents tires from punctures to reduce cost of repairs. It is important that they be filled properly and completely. Any void in the foam will cause tearing and the tire will squash out when it gets to this area. These tires will add a significant amount of overall weight to the equipment. Foam filled tires are common on rough terrain scissor lift and boom lifts.

Solid tires are not very common in the MEWP industry; however, some machines do use them. Solid tires are just as the name implies, a solid rubber tire with no air. These usually have to be mounted on 2-piece rims and may require that the tire be pressed onto the rim.

Non-marking vs standard: In most cases, non-marking tires use no carbon black in the manufacturing process of the tire. Because of this, the non-marking tires will build up static electricity as it rolls over a surface and can produce a static shock for the operator. To alleviate this problem, it is recommended that a static strap be installed on the equipment to dissipate the static charge. Non-marking tires do not leave scuff or black marks on finished floors and are common on most slab electric scissor lifts. Carbon black is added to tires to extend tire wear and prevent chunking. The higher the grade of carbon black used, the better the wear of the tire.

What factors influence the quality and reliability of tires?

The quality of the natural rubber used in the manufacturing of tires is a major factor in how long a tire will last and how well it will perform. Many manufacturers use synthetic rubber fillers and low quality rubber compounds to reduce costs. This reduces the durability of the tire and makes them more prone to punctures, chunking, and faster wear.

Another factor is the quality of the vulcanization. Vulcanization is the process of improving the rubbers elasticity and strength by heating it in the presence of sulfur.

What can I do to increase the life of my tire?

The most important thing is inspecting the area where your equipment will be operating. Avoid continually running over debris and potholes. Good housekeeping can go a long way in extending not only the life of your tires, but also the life of your machine.

Important Facts

  • On machines with pneumatic tires, check tire pressure daily and fill to the recommended pressure. A 5 psi difference in tire pressure from one side to the other or from front to back can be as much as 1º off level when elevated.
  • Watch out for nails, screws, etc. Not only can they puncture a tire, on moulded tires they can stick into tire and go in far enough to break the bond with the rim. This will cause premature failure of a tire.
  • Replace tires as a set, or at least in pairs, such as front or rear. This is needed for the stability of the machine.
  • Always use the size and type of tire recommended by the equipment manufacturer.