With tractor tyre technology becoming increasing more sophisticated and costly, treating them with care has never been more pertinent. Jane Carley runs through a few top tips.
A modern 200hp tractor, and its tyres, are required to carry out a wider range of tasks and perform both in the field and on the road.
Average tractor horsepower continues to creep up and what was historically considered to be a ‘big tractor’ at 200hp, may now be the main workhorse on many farms.
However, with tyres representing a significant cost and playing a vital role in efficiency, care must be taken to ensure they are performing to their full potential and able to meet working life expectations.
With a few simple tips, tyre wear can be reduced, fuel use lowered and overall efficiency improved.
Mitas UK technical manager Kirk Walker says nearly 90 per cent of all tyre warranty claims are pressure related.
“It is the single biggest area when it comes to damage, with low and high pressures causing irreversible deterioration in tyres.
“With a large cultivation tyre costing up to £5,000 it is an area where producers can make a big difference to costs and operating efficiency if they understand more about tyre management.
“Correct inflation pressure is crucial as it is the air inside the tyre which supports the load and transfers the power of the machine to the ground. A tyre with the correct inflation pressure will have the best footprint for traction, able to spread weight over a large area and avoid soil compaction. Additionally, the whole of the tread width will be in contact with the ground, giving a better tread wear rate and longer tyre life.”
To set tyre pressures accurately, getting individual axle weights right is key, he says.
“Set up the tractor with the piece of kit you will be using and any necessary front weights. Ideally you want to be setting the tractor up so 60 per cent of the weight is distributed over the rear axle and 40 per cent over the front.”
Michelin customer engineering support manager Gordon Brookes says irregular wear is a common issue.
“The most likely cause of this is insufficient weight being borne by the tyres to allow them to operate correctly even at their minimum pressure.”
If the tyre has a minimum carrying capacity of two tonnes but only 1,500kg is exerted on it, then he says it is significantly over-inflated, even at the tyre’s minimum operating pressure.
The problem often occurs, when front weight packs are taken off the tractor for road work.
“Tractors need the weight packs to keep the front and rear axle balanced, to maintain the tyre’s expected working environment and to maintain vehicle dynamics.”
When checking tyre pressures, he advises operators seek the tyre manufacturer’s advice and ensure the tyre is still able to flex.
One of the most significant tyre developments in recent times is the introduction of high flexation (HF) and very high flexation (VF) tyres.
Kirk Walker says VF tyres can be used at a lower inflation pressure in the field and the same pressure can be used for road work, thus making this design ideal for the range of tasks a modern 200hp tractor can perform.
The considerably lower pressures at which VF tyres work can lead to 25 per cent larger footprints so the tyres look different to conventional ones when in operation, he says.
“Much of the deflection takes place length-wise, so with a VF tyre you should be aiming to get three lugs on the ground with only minimal sidewall deflection. The greater the bulge on the side of the tyre, the harder it is to run in furrows and the more vulnerable the tyre is to stone damage.”
Get it right, he says, and you will benefit from reduced ground pressure, better traction and the ability to run high road speeds at lower pressures than with conventional equipment.
“The fundamental difference with VF tyres is the sidewalls can deform to a much larger degree than conventional tyres without causing structural damage.”
Like any tyre, set-up is key and although poor fuel consumption, rapid wear and reduced in-field performance can all result from poor management, it is an area few farmers understand properly, he says.
“I think most people still set the best operating pressure for the road and then use this in the field without realising how much soil compaction this can cause and how much extra fuel it uses through reduced traction. Few actually adjust pressures between different jobs.
“With VF tyres you have to think the other way round and optimise the pressure for fieldwork knowing you can still use this on the road without problems.”
Tractors used mainly for cultivations may be parked up for long periods and, as with other seasonal equipment, such as harvesters, tyres need to be inflated to a higher pressure to prevent the sidewall deflecting and flat spots appearing, which can affect road performance.
Gordon Brookes says: “Tyres can also suffer from ozone degradation if vehicles are parked outside or near electrical equipment. Before starting work, always check the tyre condition and pressures.”
Kirk Walker agrees. “If a machine is to be stored for a few months, ideally the wheels should be raised off the ground, however this is not always practical. The first thing to do is raise the inflation pressures up to their maximum and to store the tyres away from sunlight, cold air and moisture,” he says.
Water ballast is also becoming increasingly popular, he says, and operators should ensure ballasted tyres have anti-freeze in them in cold weather. This is worth double checking at the end of the establishment season.
Another cause of uneven tyre wear may be steering misalignment, Gordon Brookes says.
“This can be difficult to pick up in the field, but it can affect performance, so if weight and balance have been ruled out as the causes of tyre wear it is worth discussing with your tractor dealer.”