commercial tyre safety
Legal Tyre Condition
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the legal tread depth limit for truck tyres is 1mm around the whole circumference of the tyre and at least 75% across the footprint of the tyre.
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there cannot be a cut longer than 2.5cm or 10% of the section of the tyre (size dependant)the cut should also not be deep enough to touch or expose any cords.
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any tyre with bulges, flatspots, tears and exposed cords are also illegal to use.
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running a tyre with incorrect or insufficient pressure for the load it is carrying is also illegal.
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tyre regrooving must take place before the tyre is below 3-4mm of tread and must not expose any cord post regrooving.
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tyres can not be older than 10 years for road use.
our recommendation
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We completely agree with the legal requirements entirely and nothing should be exceeded.
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our recommendation for tread depth is changing your tyres before the depth becomes below 3mm or the vehicle struggles for grip in its application (extreme wet weather or off road).
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if a tyre reaches an age of over 7 years we suggest not using it on the road.
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we recommend not regrooving tyres on machines that are being used for large volumes of work.
Steps we take to ensure safety
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we torque all wheel nuts with a calibrated torque wrench to manufacturer specification or to recommended spec based on the nut and thread size.
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we look at wheel stud/nut and hub quality to ensure rims are seated correctly.
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we advise drivers check their wheel nut torque 30 miles (50km) after wheel installation.
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when servicing a vehicle we will check over the whole machine for any tyre issues/ defects.
tyre markings
The first number of the size markings relates to the section width of the tyre in mm (e.g. 315 = 315mm). the second number is the ratio and means that the sidewall is equivalent to that number as a percentage of the section width. (e.g. example tyres sidewall = 80% of 315mm). the next marking will be started with - which means it is cross ply or R which means it is a radial construction. the number following is then the rim size in inches (e.g. 22.5 inches). the numbers on the load and speed rating refers to the weight capacity that the tyre can support at full inflation. the letter then refers to the speed at which the tyre is capable of doing.
Tyre wear
tyre inflation is one of the first major things to get right for even tread wear. as the diagram shows under inflation or over inflation can contribute to greater centre or edge wear. the best way to prevent uneven tread wear is to check your tyres regularly for pressure and tread depth, then adjust accordingly. incorrect inflation will also reduce the overall lifetime of your tyre as it is wearing on a smaller contact patch and therefore quicker. for example a tyre under inflated by 20% will have its life shortened by 30%, then multiplies accordingly.
road surface also has a brutal effect on tyre life. this is why vehicles doing a job such as long haulage will have longer lasting tyres than vehicles doing shorter but often jobs on country roads such as sugar beet carting. this is because what the road surface is made of wears down the tyre at different rates. with tarmac being the base statistic offering 100% of a tyres life. Concrete surfaces wear the tyre by an extra 20%, class B roads with hills and corners 24%, country roads being an enhanced version of a b road 50%. then damaged road surfaces beyond this can effect tread life by over 70%.
blowout causes and prevention
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heat build up in tyres is a major reason for blowouts. this is caused by being overloaded, going too fast, under inflation and wheels being out of line causing rolling resistance.
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a damaged tyre structure via cuts or impacts can also cause blowouts. broken cords will mean the tyre has room to expand then potentially explode under pressure. a sudden impact could also damage cords then cause an instant release of pressure.
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blowout prevention mainly includes safe driving, avoiding objects which may hit and damage your tyres.
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routine maintenance including checking your pressures are correct and your tyres are cut and bulge free will give you the best change of avoiding blowouts.
