Get the Most From Your Investment

July/August 2016

Eric Matson at Goodyear explains why TKPH rating and tread design play key roles in tyre performance. Plus, how maintenance can help optimise your investment

Heavy haul trucks travel across extremely challenging surfaces whilst carrying enormous loads. As a result, the tyres on these vehicles are exposed to tre-mendous forces. That's why it's criti-cal for fleet and maintenance man-agers to select the right tyres for these profit-generating machines.

There are numerous factors that should be considered when select-ing tyres for your haul trucks. Assessing your mine site's 'foot-print' tops the list; before you select a specific tyre, you should have a thorough understanding of your haul truck's on-site activities.

This can be accomplished by mounting a location-tracking unit on a truck and letting the vehicle run for a designated period of time (Goodyear recommends 24 to 48 hours). This will help you develop a site map.

At the same time, you should track the distance the truck travels, its speed and the load it is carrying. Many trucks are already equipped with devices that log speed and load data.

Then you should take the average load and multiply that number by the average speed. This will give you the site's tonne-kilometres-per-hour (TKPH) rating.

Each mining tyre, regardless of application, also has a specific TKPH rating, which dictates how much the tyre can carry at a certain speed, and is then matched up with the mine site's TKPH rating.

In every case, you will want to pick a tyre whose TKPH rating is higher than the site's TKPH rating. This will help ensure that you've selected the right tyre for the site.

Tread Design

Pay particular attention to the tyre's tread design.

You might be presented with sev-eral tread design options that, on the surface, seem equally viable. However, it's what's beneath your tyre - the underfoot condition - that often dictates what tread design you will ultimately use.

Are the underfoot conditions relatively smooth? If so, a tyre with a shallower tread depth might be more appropriate. Are underfoot conditions severe or rocky? In that case, you might want to use a tyre that has a deeper tread depth, for enhanced traction and protection against cuts.

If in doubt, consult a representa-tive from your tyre manufacturer, who can help you evaluate your site's underfoot condition and make an expert product recommendation.

Whilst evaluating underfoot condi-tions, also look for other potential problem areas, including the roads that lead into and out of the site. Are these areas free of rocks and other debris that can cut into tyres? How are they manicured?

Are there things that can be done, such as laying down gravel, to help improve tyre traction? How many curves are your trucks required to navigate? How steep are the surface inclines and declines? Goodyear recommends keeping grades to eight degrees or less, whether up or down.

Maintain (And Gain)

Finally, benefits gained through care-ful tyre selection can be negated by poor tyre maintenance. Because tyres are mission-critical items - and because they represent a substantial investment - it pays to do everything within your power to optimise their performance and longevity.

Maintaining proper inflation levels is the single most effective thing you can do to achieve optimal tyre per-formance and life. Consistent, cor-rect inflation positively affects tyre wear and casing life, and can also help reduce the amount of fuel that your trucks use.

Inflation checks should be part of every pre-shift truck inspection. If that isn't feasible, check your tyres' inflation pressure at least once a day.

Beware of both over-inflation and under-inflation. Over-inflation can lead to uneven wear and make tyres susceptible to ruptures when rolling across tough terrain. Under-inflation causes tyres to flex more.

And make sure you don't overload your tyres. Under-inflation and over-loading can damage tyres.

Tyres are designed to keep haul trucks moving. Make sure that you and your team use the right tyres, and vigilantly maintain them so that your trucks stay up and running.

OTR tyre veteran Eric Matson is the global field engineering manager for the Goodyear Tire & Rubber Company's OTR tyre business.