VIENZH

Technical handbook for truck and OTR tyres

A guide compiled from Guizhou Tyre technical documents (SAMSON Truck and Bus Tyre Data Guide 2026): keep inflation correct, read wear patterns to find the cause, choose the right load index and store tyres properly.

Written by: Technical Department, Advance Tyre Trading Vietnam Co., Ltd · Updated 19/10/2026 · Source: Guizhou Tyre, SAMSON Truck and Bus Tyre Data Guide 2026, pages 26–33.

01

What inflation pressure should I use, and when should I check it?

Short answer: inflate to the vehicle manufacturer’s recommended pressure, never exceed the maximum pressure on the sidewall, measure when the tyre is cold and inspect every tyre (including the spare) before each trip.

Inflation pressure has the biggest effect on tyre life. An under-inflated tyre flexes continuously, builds heat and can separate its steel plies; an over-inflated tyre wears quickly in the centre and grips less. Always measure when the tyre is cold, that is before driving or after the vehicle has stood long enough for the tyre to cool completely.

Guizhou Tyre’s guidance: set and maintain the correct cold inflation pressure, inspect tyres frequently (cuts, cracks, bulges, penetrations) and check every tyre before driving. Keep the pressure difference between wheels on the same axle small.

Under-inflation · danger
  • Sidewall flexes, temperature rises fast
  • Steel ply separation, blowout under heavy load
  • Shoulder wear, higher fuel consumption
  • Tyre life drops noticeably
Over-inflation · risk
  • Rapid wear in the centre of the tread
  • Smaller contact patch, more prone to slipping
  • Prone to bursting on sharp objects
  • Suspension and rim take heavy shocks
On spec · optimum
  • Tread wears evenly across the full width
  • Stable operating temperature
  • Low rolling resistance, fuel savings
  • Allows safe regrooving and retreading

Source: SAMSON Truck and Bus Tyre Data Guide 2026, pages 27–30.

02

How do I read tread wear patterns to find the fault?

Short answer: centre wear usually means over-inflation, shoulder wear means under-inflation or overloading, one-sided wear means wheel misalignment. According to Guizhou Tyre, the main cause of irregular wear is a mechanical fault on the vehicle such as misalignment or an unbalanced tyre-and-wheel assembly.

The wear pattern is a trace that reads back the operating conditions. Before replacing a tyre, identify the cause so the new tyre does not repeat the old fault.

Wear patternCommon causesRemedy
Centre tread wear Pressure too high, load light for the specification Reduce to the recommended pressure
Both shoulders worn Under-inflation, frequent overloading Inflate to spec
One-side wear Incorrect camber, incorrect toe Align the steering geometry
Patchy wear (cupping) Weak shock absorbers, unbalanced wheel Dynamic wheel balancing
Saw-tooth wear Axle misalignment, tyre rotation not per schedule Rotate tyres on schedule
Sidewall cracking Ageing, sun exposure, chemicals Replace the tyre, shade the store
Sidewall cuts and tears Impact with sharp rocks, under-inflation on mine sites Choose a tread pattern suited to the terrain

If irregular wear persists after the mechanical faults are corrected, Guizhou Tyre recommends: steer-axle tyres — check the wheel alignment (toe and camber) and raise the pressure within the allowable range (100–115 psi); drive-axle tyres — adding 10–15 psi makes the tyre less prone to irregular wear.

The wear indicators on Advance truck tyres become visible when the tread depth reaches 1.59 mm (2/32 inch) in two adjacent main grooves. At that point the tyre has reached its wear limit; replace it, or check it against the tread-depth rules where it is used.

Source: SAMSON Truck and Bus Tyre Data Guide 2026, pages 27 and 32.

03

What does the load index (LI) mean and how do I choose?

Short answer: the LI is a number that converts to the maximum load one tyre can carry; choose a tyre whose load per tyre is greater than or equal to the actual load on each wheel.

The load index (LI) is the number on the sidewall that converts to the maximum load of one tyre. Truck tyres usually show two values (for example 152/148): the first for single fitment, the second for dual fitment.

LILoad / tyre (kg)LILoad / tyre (kg)LILoad / tyre (kg)
1201,4001322,0001463,000
1221,5001342,1201483,150
1241,6001362,2401503,350
1261,7001382,3601523,550
1281,8001402,5001543,750
1301,9001442,8001564,000

Source: international load index table, SAMSON Truck and Bus Tyre Data Guide 2026, page 26.

Quick formula

Load per wheel (kg) = axle load (kg) ÷ number of wheels on the axle. Single axle = 2 wheels, dual axle = 4 wheels. Choose a tyre whose LI corresponds to at least the calculated value, and allow a safety margin.

Calculate automatically with the tyre selector
04

What should I know about repairing and retreading tyres?

Short answer: have truck tyres repaired or retreaded only by trained personnel; never use a plug-only repair and never use an inner tube as a substitute for a proper repair.

A tyre repaired or retreaded incorrectly can fail without warning. According to Guizhou Tyre, SAMSON tyres should be repaired and retreaded only by trained personnel; any puncture may be repaired only after the tyre has been dismounted and its inside checked.

What to avoid

Never repair a truck tyre with a plug only. Never use an inner tube in place of a proper repair. A puncture left unrepaired can damage the inner tube and eventually destroy the tyre.

When to have a tyre checked

A tyre with a cut, crack, bulge or penetration should be inspected as soon as possible by an authorised Advance Tyre dealer. If you want to regroove or retread, ask our technical team whether your tyre size is suitable.

Source: SAMSON Truck and Bus Tyre Data Guide 2026, pages 27 and 33.

05

How should I store tyres in stock?

Short answer: keep tyres indoors in a cool, dry place away from sunlight, heat sources, oil and chemicals; stack no higher than about 1.5 m and keep the tyre interior and the compressed air dry.

Tyres in stock still age, and improper storage can cause damage that is not visible. In steel radial tyres, moisture inside the tyre can corrode the steel cords after inflation.

Storage location
  • Indoors, cool and dry, no standing water
  • Away from direct sunlight and hot air flow
  • Away from electric motors, generators (ozone) and heat sources
Stacking position
  • Keep stack height within 5 feet (about 1.5 m)
  • Keep tyres away from oil, grease, fuel and solvents
  • Clean storage surface free of grease
Before mounting
  • Inspect the inner surface and remove foreign matter and moisture
  • Keep the compressed air used for inflation free of moisture
  • First in, first out by production date

Source: SAMSON Truck and Bus Tyre Data Guide 2026, pages 27 and 31.

Technical support

Is your fleet wearing tread
abnormally?

Send photos of the tread and operating details — our technical team will review them, diagnose the cause and suggest a suitable replacement size.

Send technical request 0813 132 686