Why Australian Chevrolet Camaro ZL1s use different tyres

The standard rubber on the 2019 Chevrolet Camaro ZL1 is the Goodyear Eagle F1 Supercar 3, a high-performance tyre designed to handle the abuse of 477kW and 881Nm. But not in Australia.

Camaro ZL1s locally-converted by HSV use older-style Continental ContiSportContact 5Ps which were almost universally fitted to Commodore-based HSVs from Gen-F onwards.

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HSV would rather not make the switch. Its Camaros come fully built from the US so therefore it has to incur the cost of replacing the tyres, which it’s trying to recoup by offering the standard Goodyears as a track pack for $1000.

The reason the Goodyears can’t be used is that they failed the braking tests specified by the Australian Design Rules, specifically, ADR 31/04 test 5.3.4.

This test dictates: “When the right and left wheels of the vehicles are situated on surfaces with differing coefficients of adhesion, where Kh≥0.5 and Kh/Kl ≥2, the directly controlled wheels shall not lock when the full force is suddenly applied on the control device at a speed of 50km/h”

In layman’s terms this essentially says the wheels must not lock under heavy braking from 50km/h when the right wheels are on a high-grip surface and the left wheels are on a low-grip surface or vice versa.

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The test is a tough one, with one side of the vehicle on dry tarmac and the other on wet ceramic tiles, but nevertheless it’s one that all vehicles must pass and try as it might, the Camaro ZL1’s ABS couldn’t summon the required grip from the focused Goodyears to do so, hence the switch to the known quantity of Continental.

The US regulations, dictated by the Federal Motor Vehicle Safety Standards (FMVSS), are less taxing, completed on a level road with consistent grip across all four tyres.

An HSV spokesman explained the switch to MOTOR: “Our chassis engineers assessed three different brands for greater suitability to Australian conditions. Using a combination of GM’s Lang Lang Proving Ground and Victoria’s alpine roads, all aspects of the Conti tyre were assessed (including steering, handling and ride quality) to understand their suitability to the ZL1 Camaro.

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“Our engineers concluded that they feature excellent connection to the road and on-centre feel and provided excellent feedback through the chassis and steering on the sportiest of roads. Importantly, they also provide improved wet-weather performance and safety in variable weather conditions.”

MOTOR has contacted Goodyear for comment.