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Michelin breaks its silence
Page 28
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by David Wilcox
MICHELIN has long had the reputation of being a rather secretive company, closely guarding its tyre-making technology. Guided tours of a Michelin plant are about as frequent as appearances by Halley's Comet.
Perhaps this natural reticence explains Michelin's delay in countering what it considers to be biased and misleading information from the Retread Manufacturers' Association (RMA).
For it was five months ago at its annual general meeting that the RMA president, Stan Goodall of Cavalier Retreads, made, according to Michelin, the following statement: "I would suggest that the haulage industry re-examine the economy of regrooving. With the value of a first class casing now between 1:30 and 1:40, a three millimetre regroove represents a cost of 1:10 per millimetre if the casing is subsequently rendered unretreadable.
"In any event, regrooving is often prejudicial to the quality in the subsequent remould life. As a responsible association we need to lobby and reeducate to this effect."
At a press conference last week, chief executive of Michelin's commercial operations John Hible called this statement "misleading" and said that the RMA is trying to protect its own interests at the expense of the UK haulage industry.
The RMA has a membership of 55 retreading companies including some of the big names in the commercial vehicle tyre market such as Bandag and Vaculug.
Michelin is riot only a tyre manufacturer — largest in Europe and second in the world to Goodyear — but also a tyre retreader. In fact, it is the largest truck tyre retreader in the UK, receiving 350,000-400,(X)0 casings a year for its ''Remix'' retreading process at the Stoke-on-Trent plant.
Despite this, Michelin stands outside the RMA and this difference in opinion over regrooving widens the gap between them. While the RMA wants to discourage regrooving, Michelin actively encourages it.
A spokesman for the RMA told CM last week that Michelin is misquoting the Association's line. "What we say is that we are totally opposed to indiPrent regrooving. It is true that we do not advocate regrooving but it is all right from a safety point of view if it is done properly."
This does not alter the RMA's basically anti-regrooving stance. It admits that it has a vested interest in the subject — regrooving a tyre delays its use as a casing for retreading and if the regroov ing is "indifferent'' the casing is ruined for most retreading processes. "Obviously it is in our interests to protect our raw materials," says the RMA.
From the operator's point of view, the RMA maintains that tlw economics of regrooving no longer stand up when one considers the risk of carcass damage and the 130 to 1:40 value of a casing — it only made economic sense when the residual value of the casing was 15 to 1:6.
Michelin insists that regrooving its tyrts is both safe and economic because they are designed to he regrooved. "If any retread manufacturer is currently stating that regrooving causes the loss of a Michelin casing for retread, then that is due to that retreader's own technical or economic limitations."
According to Michelin, it is impossible to damage the casing ii regrooving is correctly done, and that cutting an additional three or four millimetres of tread into the base rubber does not make the carcass more susceptible to shock, as is claimed by the RMA.
A regrooved tyre is safer than .1 wellworn tyre says Michelin because it has better water dispersal abilities due to the extra few millimetres of tread. And the economics also work, claims the corn
party, quoting figures for an 11-22.5 XZY tyre which starts life with 15mm of tread depth. Regrooving can give a further four millimetres, representing an additional tread life of 28.5 per cent.
Michelin's own Remix retread process will happily accept regrooved tyres. During the Remix process, all the base rubber is removed anyway (unlike most other retreads which need some base rubber as a seat for the new tread) so that the steel carcass can be examined for rust spots caused by water ingress.
If necessary, the outer steel breaker strip or the bracing plies underneath can be renewed during the Remix.
This more comprehensive process explains why Michelin will retread regrooved tyres where other retreaders would not. The company boasts an 86 per cent acceptance rate for casings for Remix; 60 per cent have already been regrooved. There is a price penalty; Remix is more expensive than the average retread.
The Michelin recommended route is a regroove followed by a Remix and then a second regroove. The company is unwilling to Remix a tyre more than once, whereas most retread companies will retread a satisfactory casing twice or possibly three times.
If this Michelin formula of regroove. Remix, regroove is followed, the company says an operator gets two and a half times the tyre wear for one and a half times the cost. That, says Michelin, means a 37 per cent lower tyre bill.