New tyre heralds new era for Sumitomo in Australia

Sumitomo tyres have been sold in Australia for 30 years, but the Japanese brand has never been a household name.

However, the company is determined to change that -- having appointed Tyrecorp as its new distributor in Australia -- and introducing a new high-performance tyre, the HTR Z III.

Although the name HTR Z III doesn't exactly roll off the tongue like 'P-Zero', at least it sounds more credible than 'Continental ContiSport Contact'.

Already sold in the USA, the HTR Z III has come out the victor in a tyre comparison conducted by American website tirerack.com against the Bridgestone Potenza, the aforementioned Continental tyre and Yokohama Advan Sport.

The Sumitomo donut is billed by the company as a "maximum performance summer tyre" and is available in profiles ranging from 50 series to as low as 25 series, and to fit wheels from 17 up to 22-inch diameter.

The tyre features a silica tread compound, a flange guard to protect the wheel, a five-rib asymmetric design and a '3D wave wall'. This last feature minimises centre rib squirm.

Of the five ribs, the innermost rib is what Sumitomo describes as a "sacrificial wear control rib" -- for those occasions when too much negative camber just isn't enough.

At the Eastern Creek launch of the HTR Z III, Sumitomo and the local distributor, Tyrecorp, provided media with the opportunity to drive two Holden Commodore Omegas equipped with V6 and automatic transmission. One of the Holdens was fitted with the HTR Z III tyres and the other was fitted with an equivalent tyre from a competitor.

Although the tirerack.com comparison pitted the HTR Z III against Bridgestone Potenza, Continental and Yokohama tyres, Sumitomo and Tyrecorp chose equivalent tyres from GT Radial for the Eastern Creek demonstration of the Sumitomo's capabilities. Sumitomo and Tyrecorp consider the GT Radial counterpart to the HTR Z III to be inferior, but it is similarly priced in the Australian market.

For the testing, both sets of '+2' tyres were 245/45 ZR18 -- up two sizes from the standard 225/60 R16 tyres fitted to the Commodore Omega. Both sets were inflated to 36PSI (approximately 248kPa) and ESP remained enabled for the testing.

In a wet braking test, the Sumitomo-shod Commodore pulled up on average 1.5 metres shorter (about 25 metres from 75km/h) and in 2.4 seconds rather than the 2.6 seconds required by the competitor. G-forces generated were as high as 0.9g for the Sumitomos, versus 0.8 for the competitor. The differences were incremental, but significant.

More telling was the motorkhana course laid out with witches' hats on the skidpan. Fitted with the competitor's tyres, the Commodore understeered much sooner and the ABS and ESP both began to intervene at lower speeds. Even on wet concrete, the competitor's tyres signalled their surrender early with frequent tyre squeal around the course.

By comparison, it was harder to find the limits of adhesion in the Commodore fitted with the HTR Z III tyres, even with this reviewer's best attempts at calculated hamfistedness.

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