Super Single Conversions

Why Correct Tyre Pressure Matters — Especially for Super Single Conversions

When you move from factory duals to a Super Single conversion, you’re not just changing the look of your vehicle — you’re changing its performance envelope. Those big single tyres carry more weight per wheel, handle heat differently, and respond more sharply to under- or over-inflation.

At highway speeds, that makes tyre pressure one of the most important — and most misunderstood — factors in keeping your rig safe, efficient, and predictable.

1. Heat Is the Silent Killer

Every tyre flexes as it rolls. The more it flexes, the hotter it gets. Under-inflated tyres flex excessively, especially on heavy vehicles and loaded utes or trucks with single-wheel conversions.

At 100 km/h, a tyre that’s even 10 psi below spec can generate enough extra heat to break down its sidewall structure. That’s why so many “blowouts” on caravans, motorhomes and Super Single conversions aren’t sudden failures — they’re the final moments of hours of overheating.

Keeping pressures within the manufacturer’s recommended range (or your tyre engineer’s GVM-based advice) ensures the casing runs cooler and lasts longer.

2. Load Distribution and Stability

Super Single tyres are designed to carry more per wheel than standard duals, but only at their rated pressure. If you run too soft on the highway, that tyre shoulders a load it was never meant to.

This affects:

• Cornering stability — The tyre wall flexes too much, making the vehicle feel vague or “wandery.”

• Braking — The contact patch deforms, increasing stopping distance.

• Tyre wear — The outer edges wear faster, shortening lifespan dramatically.

On the other hand, over-inflation makes the centre of the tread work harder, reducing grip and increasing vibration, especially noticeable with large 35–37 inch all-terrains.

3. Fuel Efficiency and Rolling Resistance

Properly inflated Super Singles roll smoothly. When under-inflated, the increased rolling resistance means your engine must work harder, which burns more fuel. A drop of just 10 psi can reduce efficiency by 3–5 percent, which adds up fast on long highway runs or touring rigs.

For fleet operators or travellers towing heavy loads, correct pressure isn’t just about safety — it’s about economy.

4. Pressure Changes with Temperature

A common misconception is that tyre pressure is “set and forget.” It’s not. Air expands as it heats up — roughly 1 psi per 5 °C. That means a tyre set at 65 psi on a cool morning could easily rise to 75 psi after an hour of highway driving.

That’s why you should:

• Always check pressures when tyres are cold (before driving).

• Expect a normal pressure rise as they warm up.

• Never bleed down hot tyres — it’ll leave you dangerously low once they cool again.

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5. Tyre Pressure Monitoring Is Your Friend

If you’re running a Super Single conversion, a TPMS (Tyre Pressure Monitoring System) is one of the best investments you can make. Real-time pressure and temperature feedback lets you catch issues early — like a slow leak or one tyre running hotter than the others.

Modern TPMS kits are easy to retrofit, even on beadlock or aftermarket wheels, and can save you thousands in tyre replacements or damage to wheel bearings and suspension.

6. Find Your “Sweet Spot” — Not Just the Sticker Pressure

The factory placard is a starting point, but your Super Single conversion likely changes:

• Tyre load rating

• Axle load balance

• Rim width

• GVM / GCM upgrade rating

That means your ideal pressure may differ slightly. A good rule of thumb is to consult your tyre supplier or engineer for recommended pressures under different loads — highway, towing, or off-road. Keep a record, and use it as your baseline.

The Bottom Line

Your tyres are the only thing connecting your truck to the road. When you’ve invested in a Super Single conversion, maintaining correct pressure isn’t optional — it’s the difference between safe, efficient touring and an expensive roadside failure.

Check them cold, check them often, and trust the numbers.

Because with Super Singles, pressure is power.

Furthermore, these changes need to be certified as a HV Modification - this is required so that the correct advice is given to the owner of the vehicle, deaths have resulted in these vehicles being converted, then driven with low tyre pressures and resulting in roll overs.