Our Rover 75 is a beautiful car. It deserves to be looked after, but it has been busy over the winter months. To keep it, me, and others safe, it has been wearing a set of 18” ZT winter tyres. Don’t underestimate the benefit of winter or ‘all season’ tyres. There doesn’t need to be snow on the ground. If it is cold, they help. Just like wearing sensible shoes rather than espadrilles. An expensive luxury? Not if it prevents an incident.
Anyway, this got me thinking about the time we drove our first Rover 75 prototype to our colleagues in Munich – a Rover 620ti fitted with ‘RD1’ front and rear axle concepts (mentioned previously in these pages). It was winter and we wanted to show our professionalism. So on with a set of 205/65 R15 (the original size) winter tyres.
The journey to Munich was a pleasure as always. We usually found some interesting (if not the most direct) roads to use and included a section of derestricted autobahn. Mindful of the winter tyres (120mph limit I seem to recall), we couldn’t fully exploit the strength of the 620ti engine, but it was exciting enough.
Arriving safely, we proudly got the car on the ramp to show off our handiwork. All was fine, apart from two perfectly formed circumferential grooves in the tyre tread blocks, just below the front strut spring pan. The static clearance to the prototype parts had been around 12mm. The depth of groove suggested that the tyres had been ‘growing’ approximately 20mm at our (restricted) top speed.
Lesson learned. Size (and tyre selection) matters.