A Sign Board for retreads
By VN Ramamoorthy
Apart from the fact that cost of a retread is generally in the range of 30% of the cost of a new tyre, retread by itself is a recycling process. Scrapping and destruction of a tyre or any rubber product can cause atmospheric and air pollution affecting the environment. Hence every tyre should be recycled by a quality retreading process, as many times as
possible, to protect our environment and to preserve planet earth
What is a Pneumatic Tyre?
A tyre is a composite product that can be made out of a combination of Natural Rubber, synthetic rubber, Nylon/Rayon
cords, Steel, Oils, Carbon black and chemicals. It is an inseparable assembly of various materials manufactured to exacting standards to withstand high pressure and temperature aimed to provide traction and steering capabilities for vehicles.
What are the major types of tyres?
a) Tyres can be classified as Bias (Conventional) tyres or Radial tyres. Radial tyres are constructed with the body plies running at 90 degrees from the bead, with Bias ply tyres the body plies run at angles from the bead. Because of their construction, radial tyres tend to maintain a larger ‘footprint’ on the road during cornering and offer a smoother ride.
b) They can also be classified as Tube tyres or Tubeless tyres. In a tubeless tyre, the function of a tube is replaced by an inner liner which is an integral part of the tyre itself.
c) A tyre can also be classified with respect to its application – like Passenger, Commercial and Off the Road.
What is the major factor that influences the performance and life of a tyre?
The main factor that affects the performance and the life of a tyre is the heat generated in operation. The lower the heat generated or the faster it is dissipated, the life of the tyre is prolonged. The rubber compounds used in the construction of the tyre and of its tread also play a large role in the generation or dispersion of heat build up.
What are the major factors that affect the life and performance of a tyre?
There are many factors which influence the performance and life of a tyre. However, the three major reasons are Overload, Over/under inflation and Over-speed.
Why retread a tyre?
A new tyre can perform safely and satisfactorily only till its tread portion wears out. It is unsafe to use the tyre when the treads are fully worn out because when the tyre is bald it loses grip and also can slip/skid when breaks are applied resulting in fatal accidents. A user can enjoy only 30 to 40% of the total life of a casing till the tread portion wears out. It is therefore essential that the casing is retreaded by the user to enjoy the remaining 70% of the life left in the tyre. Retreading is also a good form of recycling as the amount of raw materials is greatly reduced through the use of retreading.
How to know when one should remove the tyre for retread?
The tyre must be removed when the original tread on the tyre wears out. This is indicated by Tread Wear Indicators (TWI) which is provided inside the grooves of the tread at various places along the circumference.
For best results, it is always recommended that a commercial tyre is removed when at least 1.6 mm of the tread is still remaining.
Is a retreaded tyre safe?
A retreaded tyre is as safe as a new tyre, provided the retreading is carried out by a qualified retreader with technical expertise using recommended quality of materials and accredited processes.
How to know a tyre is fit for retreading?
A tyre has to be inspected thoroughly based on a thorough, established inspection procedure to ascertain the strength of the
casing. Only if the strength or integrity of the casing is found fit, the tyre can be accepted for retreading for a further lease of life.
How many times can a tyre be retreaded?
This depends on the strength of the casing and the type of application. As long as the casing integrity is intact, a tyre can be
retreaded multiple times.
How does the cost of a tyre affect the user of the vehicle?
Cost of a tyre is invariably the 2nd largest expense to a vehicle user (especially a fleet operator), probably only next to the cost of fuel. Hence it is only logical that every user should control his investment on tyres by minimizing the cost of tyres or ensuring lowest cost per kilometre.
What are the factors that influence the cost and performance of tyres for a user?
There are many reasons and factors that influence the performance and maintenance like conditions of load, road, application, weather, driving habits, tyre maintenance etc. including the construction, sculpture and composites of the tyre by the manufacturer.
What are the major types of retreading processes for a commercial tyre?
Basically, there are 2 processes viz. Precured (Cold) process and Conventional (Hot) process. The process to be chosen for a particular tyre depends on the condition of the tyre and its casing strength.
Can the Bias (Nylon) and Radial tyres of the same size be mixed and used in the same vehicle?
The construction of a Bias (Nylon) tyre and that of an equivalent size of Radial tyre are entirely different. Therefore, it is not recommended to mix Bias and Radial tyres in the same axle of a vehicle. Nor should they be used in combination with the same vehicle.
What is the significance of a retreading process?
Apart from the fact that cost of a retread is generally in the range of 30% of the cost of a new tyre, retread by itself is a recycling process. Scrapping and destruction of a tyre or any rubber product can cause atmospheric and air pollution affecting the environment. Hence every tyre should be recycled by a quality retreading process, as many times as possible, to protect our environment and to preserve planet earth.
How to choose a retreader?
It is always best to choose a retreader who has the best practices and expertise for inspection and process standards using quality inputs. It is unwise to choose a retreader only on the basis of price as it endangers the performance and safety of the tyre, vehicle and the goods or the passengers carried.
Is price of retreading important?
The price of retreading a tyre per-Se is not important. However, it is very important to choose a retreader who can give the user the lowest cost per kilometre or lowest cost per hour than choosing cheaper options.
Apart from the cost of retreading or CPKM (Cost per Kilometer), what other factors are important for a user?
Apart from the cost of retreading, it is very important to ensure ‘Safety’ of the tyre and its operation. Hence it is of paramount importance for a user to ensure the safety of the vehicles, goods and passengers.
How to educate the operation and maintenance personnel on Tyre Care?
A detailed and structured Tyre Care Training for every user is available. You only need to find an accomplished Tyre expert to educate.
What are the most common types of abnormal wear on tyres and the reasons?
Excess/Rapid shoulder wear – Under-inflation
Excess/Rapid centre wear – Over-inflation
Spotty wear – Defective wheel balancing / Mechanical irregularity
One-sided wear – Defective camber
Feathered edge wear – Incorrect Toe-in / Toe-out
Channel/Groove cracks in tread – Over-loading / Over/Underinflation
When to check the inflation (air pressure)?
The air pressure should always be checked when the tyre is cold – preferably in the morning. Inflation should never be checked when the tyres are hot or after a trip.
What is “Dual matching”?
It means matching of two tyres by a set procedure before they can be selected for a dual fitment position. Standard procedures are available for dual matching for different sizes of tyres. If the pair of tyres is not matched for dual fitment, it can result in failure of the tyres resulting in costly loss or fatal accident.
* VN Ramamoorthy is former CEO of TVS Tread, the retreading arm of TVS Group. He can be contacted by email: firstname.lastname@example.org or Mobile: 9380294636 / 8056138559