Badly aligned or worn tyres can lower machinery performance, as well as cost you money. Firestone's Graham Pritchard provides some guidelines on keeping them in shape. 

Tyre wear

A new set of front tyres can be ruined by shoulder wear. If the symptoms are spotted early enough, the tyres can be switched from side to side – as long as the problem is then redressed. If not, the wear life of the tyres reduces dramatically.

With a typical set of front tyres costing between £500 and £800, taking practical action can deliver a considerable saving.

Alignment

Incorrect wheel alignment is a common cause of irregular tyre wear. This can be costly, not just in replacing the tyres but also in fuel efficiency, particularly when on the road. Roads are least forgiving when the rubber is pushed sideways on wheels that aren’t parallel.

Here’s how to check and adjust tracking yourself. It may be useful to refer to the Operators’ Manual for your tractor. If you’ve mislaid it, your local dealer may be able to help you.

The advice here is general, but it applies to the majority of current tractors. You will need something to measure the distance between the wheels; a telescopic pole is best, but a tape measure will suffice if you get someone to help you.

Wheel alignment is best carried out after checking (and resetting if necessary) the track width. In an ideal world, the wheels should be parallel, but as adjustments can usually only be made in increments of several millimetres, a slight toe-out is preferable to a slight toe-in because of the toe-in pressure under load, such as braking.

• Measure the distance between the wheel rims at hub height at the front and rear of the wheels. Compare the two; if the distance is greater at the front, you have toe-out; if at the rear, toe-in.
• If adjustment is necessary, loosen the locking nut on the track control rod.
• Remove and discard the self-locking nut, usually located on the end of the track control rod. You may need to apply downward pressure on the top of the screw as there is a ball-bearing in the assembly that may cause the nut to spin.
• Extract the track rod end (again, some force may be needed).
• Screw the track rod end into or out of the track rod to shorten or lengthen the assembly as necessary.
• Reposition the wheel as appropriate and reinsert the track rod end; when the wheels are parallel secure with a new self-locking nut. Do not be tempted to re-use the old one as they have a nylon inner which will have been ‘moulded’ to the previous position.
• Finally, retighten the lock nut on the track control rod. This 20-minute job could save you hundreds of pounds.