Tyre Sizes

Sir,

It appears that our correspondence with Mr Daws (Motor Sport, September) has failed to re-assure him that the slightly smaller dimensions of the Goodyear G8 crossply tyres he purchased would not affect either his car’s performance or the life of the tyres.

However, we would like to take this opportunity to answer the points he raises.

1. Whilst the tread on a tyre wears during its life the cover will actually “grow” and* worn tyre could therefore be “larger” than a new one. It is generally recommended that tyres should be replaced Ill pairs unless, of course, a comparatively new tyre on one wheel is damaged and has to be replaced. In this-case, the slight difference Mr Daws refers to would not affect the car’t performance and normally would not be noticeable.

2. The discrepancy in sires does not generally extend to radial tyres for these are produced from moulds which conform to the ETRTO specifications whereas some crossply tyres including size 590-15, the sidnect of Mr Dews complaint. are produced from moulds conforming to the then existent SMM&T standards which of course are still acceptable.

It should be understood that existtng European standards permit 1.5% over nominal overall diameter.

3. We believe that the life of our crossply tyres at lent as good as any competitor’s crossply tyres and experience has shown that very high mileages can be obtained from them

4. the slight difference in the mac of tyres would not benefit any tyre manufacturer in the manner Mr Daws suggest, neither wilt this decrease the tyre’s performance.

We hope that an independent expert will reply to Mr Daws but in the meantime we would emphasise that these differences are extremely small and do not lead to an inferior performance from the tyre.

Wolverhampton. I. Mitchell,

Manager, Service Department,

The Goodyear Tyre St Rubber Co. (GB) Ltd.