We have received many letters on the subject following Mr. Clarke's proposition last month to change the tyres on his Volkswagen each 5,000 miles to get even tyre wear when selling the car at 15,000 miles.
Nearly every reader points out that using five tyres (including the spare, of course), changing the wheels round every 3,000 miles will give an even rate of wear when the car is sold. It would need a computer to work out some of the variables in wheel changing and, indeed, Roger North wrote from a bed in Guy's Hospital to tell us that there are 120 different ways in which five wheels can be arranged.
From Betchworth, Surrey, Richard English writes: "Mr. W. D. J. Clarke, who has, no doubt, given himself quite a headache trying to calculate how to get the best wear from his Volkswagen's tyres, could have saved himself the trouble. After 15,000 miles it is unlikely that any of the tyres will be more than a quarter worn, even with the briskest motoring. In any case, the tyre wear on Volkswagens is so even that rotation is hardly worth while, even if Mr. Clarke decides to keep his for the 40,000 miles or so usually necessary to wear out a set of VW tyres in normal driving."
Mr. Barry Hughes, from Edinburgh, remarks: " I note that both the Michelin and the Pirelli rotations recommended for the Alfa Romeo (on page 8) are notably uneconomical in jacking operations. The Pirelli system requires three separate operations and the Michelin four, plus a pile of bricks when swopping o/s rear with n/s front and vice versa. However I believe that some authorities now consider it inadvisable to change the wheels around at all, on the grounds that there is a rapid rate of wear when a tyre is first placed in a particular position, which steadily decreases with time. The roadholding may also suffer for a few hundred miles after a change round and each wheel will require to be dynamically rebalanced. " Incidentally, why get a VW at all if a mileage of only 15,000 is proposed? "
Mr. Clarke labelled his wheels A (n/s front), B (o/s front), C (n/s back), D (o/s back) and S (spare). Mr. F. G. Smith from Derby, was quick to point out that using the method recommended in the VW handbook and changing the wheels every 3,000 miles, each tyre would have done 12,000 miles on each corner and 3,000 in the boot when the car was sold. Using the lettering system, the recommended rotation is S to B, B to D, D to A, A to C, and C to S. Mr. Smith adds: " Manually this is the best labour-saving method of wheel changing, as the car needs to be jacked up only once on each side. Don't forget to check valve clearances when the rear wheels are removed."
Dr. C. Casemore, of Barnes, suggests a similar operation which, however, involves two more jacking operations, or else a pile of bricks, though achieving the diagonal changes which take heavier camber wear into account each time the wheels are changed—ideal, possibly, but of no overall benefit. His rota is S to A, A to D, D to B, B to C, and C to S.
Similarly Mr. Nigel Denyer, of Gravesend, suggests a system involving two diagonal changes, this being A to C, C to B, B to S, S to D, and D to A.
Much more simple is Mr. J. K. Milner's suggestion, from Wimborne, endorsed by Mr. North and Mr. C. J. Burridge of Solihull. They suggest moving each wheel, including the spare, one position round clockwise each 3,000 miles. This is easy to remember, perfectly effective, and does not involve any diagonal changing; even tyre wear is obtained at 15,000 and 30,000 miles, or at 45,000 for the really economical driver.
Like most other readers, Mr. Trevor Davies, of Aberystwyth, favours the Pirelli routine (A to C, C to B, B to S, S to D, D to A) involving three jacking operations to Michelin's, which calls for four operations and only allows A and D to change each time. In fact, the spare would never be used on A, where in Britain most wear takes place due to camber. Mr. Davies comments that he will change his Michelins diagonally at 15,000 miles, when they are half-worn, to save a lot of trouble, and keep the spare in good condition. There were more letters with other permutations, and a strong feeling too that it is better not to change the wheels at all. The logic is that the front or rear pair will wear faster and that the first replacement equipment will be one new tyre to match the unused spare, later, a new pair will be needed and at least the tyre bills can be spread over a period. Once the spare has been brought into use, there is no need to have a meaty tyre locked up in the boot. If you must rotate your tyres, clockwise (or anti-clockwise) movement seems to serve the purpose very well.—M. L. C.