STARCO Safety Wheel

Domestic and industrial users today have access to a wider range of wheeled equipment such as wheelbarrows, sack barrows, industrial carts and powered lawn-mowers - most of which are fitted with pneumatic tyres; and an increasing proportion of which are fitted with plastic wheels.

An increasing number of households and businesses own a compressor. Most hardware stores, builders' merchants and large supermarkets that sell tools, also sell compressors capable of delivering over 8 bar.

The danger of inadvertent excess inflation is as old and as well understood by professionals as the pneumatic tyre itself. Until recently, small wheels and tyres were not considered hazardous, as the risk of tyre or inner tube explosion is relatively low, and such explosions on small tyres are usually quite harmless.

But with the increasing popularity of plastic wheels, which many manufacturers choose because of their durability, low cost and styling, the risk of personal injury due to inadvertent excess inflation is all too real.

This risk is also compounded by the fact that it is precisely such lightweight wheeled equipment that is often repaired by its unsuspecting and untrained owners, for whom the services of a professional tyre workshop may seem unnecessary when solving a simple problem such as a flat tyre.

The combination of plastic wheels; readily available, powerful hobby compressors and the untrained repairman has become a dangerous cocktail.

Controlled excess inflation tests undertaken by STARCO engineers have proven beyond all doubt that a plastic wheel will usually fail before the tyre bursts. The degree of danger is dependent on the type of plastic involved, as well as its age and temperature. Many plastics in common use will often shatter and explode - especially at low temperatures. If this occurs the wheel will become fragmented, with the explosion casting plastic shrapnel in all directions. Outside a controlled test environment such an explosion could have fatal consequences.

As Europe's leading manufacturer and supplier of wheels and tyres, STARCO recognised the need to make plastic wheel technology safer for the end user, and more attractive for the original equipment manufacturer or aftermarket distributor; many of whom have foregone the benefits of plastic wheels because of the risks associated with the end-users' own repairs.

Following a two-year research and development effort, STARCO have achieved a simple and unique solution to this problem

The STARCO "Gizmo"

The plastic safety wheel from STARCO is fitted with a patented pressure-release valve - a proprietary rubber plug, which ejects and releases tyre pressure, should inflation reach a pre-defined maximum level. When released, the valve-plug is retained in the wheel and may be reset manually.

Though the idea is simple, the development of the release valve has been demanding. Many designs and compounds were developed and tested before STARCO was confident that the device could be calibrated to specific applications and pressures.

Traditional engineering methods and approaches to this problem that have been employed in hi-tech wheel applications; such as seen in the aviation industry, were deemed unsuitable because the design brief called for a simple, single-component solution which could be mass-produced and incorporated economically in to otherwise standard wheel designs.

STARCO is now introducing this device on a new range of plastic safety wheels that comprises a wide range of popular sizes and axle options. The concept is also being further developed in cooperation with a number of STARCO's strategic partners in the industry.

The aim is to persuade original equipment manufacturers, aftermarket stockists and end-users to adopt this technology in the future, thus eliminating the danger of personal injury due to inadvertent excess inflation.

Whilst the basic concept can be implemented on many existing wheel designs, STARCO recognises that the launch of the pressure-release valve will create new markets for plastic wheels, as manufacturers and users become confident to adopt plastics as a viable and attractive alternative to steel and allow wheels.

A new product range

Starting in 2007 STARCO released a new range of plastic safety wheels, all of which incorporate the safety device.

STARCO plastic safety wheels are designed and engineered in-house - either directly for the company's own catalogue, or as bespoke versions for major manufacturing and aftermarket customers.

The wheels are tooled and manufactured at the STARCO DML facility in the UK. In-house CAD technology, tool making and injection moulding enables STARCO to develop a comprehensive product range which comprises many popular wheel sizes and colours, with bespoke design and customised colours an option for the customer.

With the inclusion of several axle-bush options this range of wheels is compatible with most popular rolling and driven axles.

Safety, performance and endurance

In anticipation of the many new applications for plastic wheels that the safety device will herald, STARCO engineers have tested all new plastic safety wheels to ensure that, besides the integrity of the safety device, the products will also meet or exceed the engineering specifications for performance and endurance.

In one of these endurance tests, a plastic safety wheel with a plain axle bush was tested on a rolling road - simulating a wheelbarrow wheel loaded to 125 kg, running for over 1000 km at 5 km per hour.

Subsequent evaluation and analysis did not reveal any significant wear or distortion of the plastic wheel or the axle bush. Furthermore, the wheel itself had no adverse effect on the tyres used in the test.

Such endurance tests at STARCO always exceed the demands that may be expected in normal use.

A better wheel

The STARCO range of plastic safety wheels gives the manufacturer, aftermarket stockist and end-user access to a better wheel.

Although the pressure-release device is a major innovation for this product, it is only a part of the overall enhancement which also includes improved design options, improved materials, more flexible tooling and manufacturing with a product engineering phase and the documented testing that lays the foundation for a very successful product.

Please contact STARCO for further information about the range of plastic safety wheels.