BRIDGESTONE S20 OE
FITTED TO THE KAWASAKI Z1000SX
Actually, it’s a lie to say we fitted the S20s to the Kwack – they’d been already chucked on by the men at Kawasaki over in Japan. The final spec of these OE tyres isn’t really decided by Bridgestone. As in the case of all OE rubber, tyre firms are given a brief by the bike manufacturer in terms of what they want from a tyre, and instructed to provide a suitable end product. As Gary wasn’t privy to Kawasaki’s design brief he said it was difficult for him to comment on the performance of the S20s fitted to the SX.
“OE tyres can vary either subtly or completely differently to the standard aftermarket version of the tyre. Profiles, compound, carcass materials, construction, tread pattern and depth, or even the overall size of a tyre can vary to lesser or greater degrees. They can end up being completely different to the stuff you buy over the counter,” said Gary.
On the road the S20s felt fairly decent. Grip, feel, steering, wet performance was all good enough for us not to complain. But ultimately it was the two key aspects of heavy weight and crude suspension that decided the limit of the bike and tyre’s progress. At Oulton, the S20s were okay, but no more. The bike’s electronics looked after us well enough whenever we got too giddy with the throttle or brakes, though again that was probably more of a reflection of the parameters set by Kawasaki’s technicians than the absolute grip of the rubber.
They were asked to do a tough job, and the combination of fairly big power, relatively poor wheel control and needing to support a lot of kilos began to show. There was a vague feel whenever you pushed the bike really hard, and the roughed-up look of the rubber showed the strain they’d been put under. Gary was keen to defend the tyres and added that, unlike the standard over the counter S20s – which have since been superseded by the S20EVOs and S21s – the ones on the Kawasaki may well have not been designed for trackday use. Whatever, just like the bike itself, they were fine up to a point, but it was always wise to respect their limits. For all we know, Bridgestone may have been instructed to make a more durable version to give significantly better mileage.
The OE S20s did a job, but not much more. If you wear them out this far, you’re doing well! And may need some new ones... The Bridgestone range section we care about!