Tyre retreading, (also known as tyre remolding or recapping but the process is different), is a process in the tyre industry that involves refurbishing worn or damaged vehicle tyres to extend their useful life. Instead of disposing of old tyres, retreading allows for the replacement of the tyre's worn tread with a new tread, providing a cost-effective and environmentally sustainable alternative to purchasing entirely new tyres.

Here's how it works:

Inspection: Old tyres are first inspected to determine their suitability for retreading. Tyres with minor or superficial wear and without significant structural damage are generally good candidates.

Buffing: The old tread on the tyre is mechanically buffed or removed using specialized equipment. This prepares the tyre's casing (the structural part of the tyre) for the application of new tread.

Reinforcement: If necessary, any internal damage or structural issues in the tyre casing are repaired or reinforced.

Tread Application: A new layer of tread rubber is applied to the prepared tyre casing. The new tread can be custom-designed to match specific requirements, such as highway use, off-road use, or commercial trucking.

Curing: The retreaded tyre, with its new tread, is placed in a curing chamber or mold and heated. This process vulcanizes the tread onto the tyre casing, creating a strong and secure bond.

Final Inspection: After curing, the retreaded tyre undergoes a final inspection to ensure quality and safety. This includes checking for any imperfections and ensuring the tread is securely attached.

What is the difference between tyre retreading and tyre moulding and when is the one used over the other?

Tyre retreading and tyre molding (also known as tyre recapping or tyre remolding) are related processes in the tyre industry, but they serve different purposes and are used in distinct situations. Here's a breakdown of the differences between the two and when each is typically used:

Tyre Retreading (what we are looking at):

Purpose: Tyre retreading involves refurbishing an existing tyre by replacing its worn or damaged tread with a new tread. The tyre casing (the structural part of the tyre) is reused, and only the tread is replaced.

Process: The process includes inspecting the old tyre, buffing or removing the old tread, reinforcing or repairing the casing if necessary, applying a new layer of tread rubber, and curing the tread onto the casing.

Tyre Molding (Recapping):

Purpose: Tyre molding, often referred to as recapping, involves applying a molded, pre-cured rubber cap (often called a "tyre cap" or "recap") to an existing tyre casing. The entire tyre surface is covered with the cap, including the tread area.

Process: The process includes preparing the tyre casing, applying the new cap, and curing the cap onto the casing. The cap typically includes a new tread pattern.

The main difference between the processes is in the amount of new rubber the worn-out tire receives. Remolded tires are covered with the new rubber from bead to bead, while pre cure retreads only get a new tread area.

In summary, the key difference between tyre retreading and tyre molding is in how much of the tyre is replaced:

Tyre retreading replaces only the tread on the existing casing and is commonly used for commercial and heavy-duty vehicle tyres.

Tyre molding (recapping) involves applying a molded cap to the entire tyre surface, including the tread, and is often used for passenger car and light truck tyres.

Tyre retreading is typically used when the casing is in good condition and capable of multiple retreading cycles, while tyre molding is more suitable for passenger and light truck tyres when a less expensive and quicker solution is needed to extend tyre life.

Tyre retreading offers several benefits, including cost savings, reduced environmental impact, and conservation of resources. It is commonly used in the commercial trucking industry, where large fleets of vehicles rely on retreaded tyres to reduce operational costs. There is also a school of thought - from those who have had to dodge the rubber on the highway - that believes that these machines should not exist and that tyres should not be retreaded at all. That being said modern endless ring type retreads have a lower failure-rate than the wrap around butt-spliced type.

 

The quality of the retreading process plays a critical role in ensuring the safety and performance of the retreaded tyres.

If you have done a search for "tyre retreading equipment" on a B2B platform you might have gotten a lot of different equipment that seem like they do different things. This is because tyre retreading is essentially a four step process:

1. Inspection
2. Buffing
3. Building
4. Curing

And what you are seeing are different machines for different parts of the process buffing machines and vulcanization chambers. Some machines can only perform 1 task, others 2, and others 3 etc. And many Chinese suppliers only sell one type of machine and the search results mix all these together. Now these four machines can be bought seperately from four different suppliers or they can be bought from one or you can buy machines that can buy more than one thing. This equipment is not cheap and trying to source the four from the cheapest source usually leaves you with four problems rather than just one.

Research & Immerse
To educate ourselves we will be looking at the four types of machines from a well known supplier. This is a common strategy in the "research and immerse" phase because well known suppliers while usually the most expensive have the most extensive documentation and the best support. Once you are familiar with the business then you can start scouting on price once you know what you are looking for.

There are two methods that can be used for tyre retreading: hot retreading and cold retreading. Only carefully selected and properly inspected casings are used in either of these methods. The manufacturing process itself is also identical for both methods, up to point of applying the tread material and performing the vulcanisation.

Passenger, light truck & 4x4 workflow

Example passenger, light truck & 4x4 ©Marangoni

Inspection
Casings go through an initial visual inspection which sometimes is also supported by a pressure test; at this stage some casings will be rejected while the others will go to the next step of the process the buffing.

Example inspection machines:

VTT Lynx

Automatic cycle machine suitable for inspecting both inside and outside of tyres for passenger and light commercial vehicles from 10” to 17,5”. The inspection can be performed under the best working conditions since the tyre rotation is carried out at even speed, without any vibration and with a strong lighting supplied by a lamp collocated in the middle of the tyre. Rotation is possible in both directions and can be stopped in any position. As soon as the 360° rotation is completed, the machine puts itself in rest position automatically. Optional: Central roller group.

PTT Passenger – Pressure Tyre Tester & Trimmer

Machine with automatic cycle suitable for inspection under pressure of passenger, 4x4, light truck tyres in the range 10”-17,5”. The inflating pressure is adjustable from 0 to 6 bars. This machine has two rotation speeds for a quick check of the casing and is equipped with safety devices in order to be in compliance with the current safety regulations. Furthermore the automatic inflating machine enables the trimming and the final checking of the retreaded tyre.

Buffing
On the buffing machine the residual tread is removed and the two sidewalls are brushed.

After buffing the process foresees the casings preparation, with the activities of skiving, repairing, filling and cementing, all aimed at having the casing ready for the building process.

Example buffing machines:

Eagle P 2004

Electronic Buffing machine designed to buff passenger, 4x4, light truck casings in the range 10”-17,5” in the standard version, or in the range 14”-22” in the latest version with reinforced chuck unit. The machine is equipped with 2 vertical buffing heads working on 4 axis, and is particularly suited for retreading plants willing to combine high volumes with the high precision of a 4 axis buffing machine.

 

The bead plate chuck system allows quick replacement of bead plates and mechanical adjustment of the bead width. The program enables to set up to an unlimited number of buffing recipes with an easy programming system of the parameters.

 

Other main features:

Automatic blade-wear compensation

Automatic program to invert rotation of buffing head

Display with actual circumference of the buffed tyre

Automatic cycle joystick operator for manual operation

Control of total and partial production, both nr of cycles and type of programs performed

Blade cooling system

Reinforced brushing unit for sidewalls of 4x4 tyres ( nr. 2 motors, 5.5 kW/each )

Circumference measuring device

Soundproof enclosure can be offered upon request

Eagle P 1003

Buffing machine with CNC designed to buff passenger, 4x4, and light truck casings in the range 10”-17,5”, equipped with 1 vertical buffing head working on 3 axis. The bead plate chuck system allows quick replacement of bead plates and mechanical adjustment of the bead width. The program enables to set up to an unlimited number of buffing recipes with an easy programming system of the parameters.

 

Other main features:

Automatic blade-wear compensation

Automatic program to invert rotation of buffing head

Display with actual circumference of the buffed tyre

Automatic cycle joystick operator for manual operation

Control of total and partial production, both nr of cycles and type of programs performed

Blade cooling system

Reinforced brushing unit for sidewalls ( nr. 2 motor, 3,0 kW/each )

Including soundproof enclosure and circumference measuring device

Building

In the retreading business there are several methods of building the tyre Marangoni is the application by a cold feed extruder with the strip winding method.

Example building machines:

Constrictor P

Automatic Stitching and building machine for sidewall of passenger, 4x4 tyres by using precalendered sidewall rubber; different chuck sizes can be applied on the chuck unit and the cycle is fully automatic.

 

A pre-cut unit can be added to the machine as an optional.

Omega Xtruder 90

Fully automatic Building machine made by 1 cold feed extruder with 90 mm diameter, designed to apply tread on the buffed casings with the strip-winding method.

 

Version for passenger, 4x4, light truck tyres can be equipped with chuck unit for tyre sizes 10”-17,5” (pneumatic opening), or 13”-20” (hydraulic opening).

Curing

The built tyre is then moved on the final step of the process, the vulcanization in curing presses. These are autoclaves what usually look like chambers or submarines.

Example curing machine:

Curing press

 

Curing press for passenger, 4x4, light truck tyres with special locking system that allows perfect alignment of the mould segments and can grant a longer life of the machine and of the moulds; different sizes available in the versions with curing tube, bladder or tubeless.

 

Presses made by 6 segments, heating by saturated steam, multifluid inflation system by air/nitrogen/water/steam. Electronic control by PLC and safety equipment in compliance with CE regulations.

 

Different options available, such as the centralised greasing system, special thermal insulation, electrical heating.

Sourcing

This is one of those times that if you want to see a demonstation of a certain machine then you are more likely than not going to have to either make a friend at a retreading shop or get into a plane and visit the manufacturer in China, US, UK. No trader will deploy a house value's worth of capital to have a tyre retreading setup taking up space on the floor. You will get that at the manufacturer or agent and our market is too small for that type of agent. Now you will maybe get Chinese selling cheap Alibaba-imported smaller motorbike tyre machines here but I am referring to specialised setups.

Should you source piecemeal?

Sourcing piecemeal will almost-always be cheaper if you shop around enough. But sourcing four different machines from unknown suppliers will be a massive risk unless you using a sourcing agent that have work with that supplier before and has minimum comebacks.

Should you source used/secondhand?

This will obviously be cheaper if the equipment is already in SA and the owner has gotten some use out of it (recouped some of initial investment) but we have looked out before on the used market and liquidation circuit and they do not come onto the market very often. We have even looked at purchasing equipment as part of a going concern and then selling off some the parts piecemeal to end up with the equipment but most tyre businesses that end up on the market are fitment centres and not retreading shops.

Which machines should you source when you cannot inspect it?

When you enter a new arena common sense tells you to operate like the others do or do as the Romans and one of that ways is to go to a retread shop and see what equipment they are using. Some will have old equipment no longer available others might even have custom equipment. But we know we have shops in SA using TRM and Marangoni Ringtread systems because they brag about it on their websites. We can also tell from the other types that they are being supplied by both Leader Tread / Milemaster, Bandag, Recamic and Chemvulc so to source the retread material locally is not a problem.