Forklift Tyre Replacement: Solid vs Pneumatic

Tyre condition is one of the most overlooked factors in forklift safety. Worn tyres do not just affect ride quality — they reduce load stability, lower the effective load rating, and cause OHS non-compliance that puts both operator and employer at legal risk. This guide explains the two main tyre types, how to know when replacement is required, and what the replacement process involves.

Solid Tyres vs Pneumatic Tyres

When to Replace: Solid Tyres

Solid forklift tyres have a moulded wear indicator line, also called the safety line or 45mm line. This line is moulded into the tyre compound at a height of approximately 45mm from the base of the tyre. When the tyre has worn down to this line, the tyre must be replaced — continuing to operate beyond the wear line exposes the steel band to the ground and causes severe rim damage, in addition to the stability and load-rating consequences below.

Operationally, you can identify a tyre approaching replacement when you notice increased vibration through the floor and cab, when the machine sits noticeably lower than its previous ride height, or when you can see the moulded wear line approaching the running surface. Do not wait for the line to disappear entirely — the tyre should be replaced when the wear line becomes clearly visible.

When to Replace: Pneumatic Tyres

Pneumatic forklift tyres should be replaced when tread depth falls below 3mm across the contact area, or when any section of tyre shows chunking (pieces missing), cracking in the sidewall, or exposure of the carcass cords. Foam-filled pneumatic tyres should be replaced when sidewall cracking allows moisture to penetrate to the foam core — the swelling and distortion that results causes uneven load bearing and lateral instability.

Inflation pressure in air-filled pneumatic tyres must be checked at every service and maintained within the manufacturer's specified range. Underinflation dramatically increases sidewall flex and heat generation, shortening tyre life and increasing the risk of sudden deflation under load.

What Worn Tyres Do to Your Machine

The consequences of operating on worn tyres go beyond ride comfort:

• Lateral instability

  Worn solid tyres reduce the contact area and change the tyre's compliance characteristics, increasing the tendency for the forklift to tip laterally when cornering with a load.

• Reduced effective load rating

  The load rating stamped on the tyre assumes the specified tyre dimensions. A worn tyre with reduced height and changed geometry effectively reduces the machine's safe working load — the load chart is no longer accurate.

• OHS non-compliance

  The OHS Act requires that plant and machinery be maintained in a safe condition. A forklift with tyres worn beyond the manufacturer's replacement specification is legally non-compliant and may not be operated.

• Rim and bearing damage

  Solid tyres worn beyond the safety line expose the rim to direct road contact. The resulting impacts damage the rim flanges and transmit shock loads through the wheel bearings, leading to premature bearing failure.

The Press-Fitting Process

Solid forklift tyres are not bolted or glued on — they are interference-fit onto the steel rim, meaning the tyre bore is slightly smaller than the rim diameter at room temperature. Fitting requires specialised equipment:

1. The wheel assembly is removed from the axle and the worn tyre is pressed off using a hydraulic press — this requires significant force and cannot be done without the correct tooling.
2. The rim is inspected for corrosion, cracking and flange damage, and cleaned.
3. The new tyre is heated in a hot bath (typically 80–100°C) to expand the bore to a diameter that allows it to be pressed onto the rim without force.
4. Once positioned, the tyre cools and contracts onto the rim, creating the interference fit that holds it in place without fasteners.
5. The wheel is reinstalled on the axle and torqued to specification, then the machine is test-operated before return to service.

This process cannot be performed safely or correctly without the press, heat bath and appropriate tooling. “Cold pressing” a solid tyre without heating risks cracking the tyre compound and creating an improperly seated tyre that can separate from the rim under load.