Talking tyres
with Dunlop, Goodyear, Firestone Racing Men
Dunlop
Heading Dunlop’s International Racing and Rally Service is Dick Jeffrey, Sales Manager (Racing) for the Birmingham Company. Mr. Jeffrey is responsible for policy within the racing department and kindly answered our first question.
For the answers to our technical questions we turned to Chief Racing Designer Iain Mills, a youthful 29, who was born in Glasgow. His family moved to Rhodesia while he was still toddling around in his (Dunlop?) bootees and he was educated both in Salisbury and later at Cape Town University, studying Chemical Engineering. Mills’ first return visit to the UK, in 1963, was on behalf of the local branch of Dunlop and his brief was to do a production/technical study on the then new SP range of radial tyres. He returned home last year, and does-so every year to visit his Rhodesian-based family.
Joining the Dunlop Group International in 1966, Mills began his designing life on truck and bus tyres, but he moved into racing in 1967 and became responsible for design nine months later. He continued the work begun on depressed crown tyres started by the late Vic Barlow, but emphasises that Dunlop design is a team effort. At the race tracks Mills’ blond hair is almost as distinctive as Jeffrey’s, while in charge of Service is Alex Meskell, a 33-year-old Liverpudlian with a perpetually serious face, whether things are going well or not.
The Dunlop service is as much connected with rallies as it is with racing and a large staff looks after the interests of both aspects of the sport.
Although they have their own road cars, the Dunlop staff share a Ford Zodiac built to police specifications (with 3-litre engine but no blue lights): it runs on 70-series Dunlop SP68 tyres.
Goodyear
In terms of annual sales of tyres, Goodyear is the World’s largest tyre manufacturer. Manager of Racing for the Goodyear International Corporation is 33-year-old Leo Mehl. Born and raised in West Virginia, he has a degree in Chemical Engineering and went straight to Goodyear in the Development Department after three years in the US Air Force. The Company gave him his first insight into racing because until he was sent to his first stock-car event in 1963 he hadn’t even seen a car race! It was also a start in racing for Goodyear, who hadn’t previously competed.
After a year with the stockers he was transferred to work on sports cars, where he spent three years, including a spell as part of the Ford assault on Le Mans when his opposite number at Firestone was Bob Martin. There followed a spell looking after the interests of the USAC cars, which included three solid months of the year at Indianapolis and supervising tyres for the USAC dirt-track ovals.
Mehl came to the UK in October 1967: he is a married man and has made his home in Wolverhampton, not far from the impressive Goodyear tyre complex. Unlike his two rivals, he is in total control of all aspects of the racing division and has his own production unit turning out racing tyres with designers and other staff in offices just behind his own. Goodyear also has an extensive commitment to rallying through Ford, but this side of the operation is budgeted by Goodyear England.
As a road car he runs a Cortina 1600E, which he likes very much: it is fitted with rallying “Grand Prix” radial tyres in the special racing mix mentioned in this article.
Firestone
Born in Akron, centre of the American tyre industry, some 40 years ago, Bob Martin’s full title is Manager of the Firestone International Racing Division. He joined Firestone from another company 15 years ago “because of the golf course and country club”, and moved to the Racing Division at the end of 1959 at his own request. He has a Bachelor degree in Mechanical Engineering which helped get him into the Racing Design Department in 1962, when he began working on high-speed runs at Bonneville and at the NASCAR race tracks. After three years of that he became attached to the Chaparral team and then moved to the UK at the end of 1964 to help with the Firestone tyre testing which Bruce McLaren, the first European constructor to use Firestone tyres, was trying.
Firestone started manufacturing racing tyres at the huge Brentford plant on London’s Great West Road in 1968, when Martin became a full-time administrator. He is very much a European now and attends all major Grand Prix and Manufacturers’ Championship events. His family moved to England on a permanent basis in 1965.
Like his two opposite numbers in the two rival companies, Martin has a Ford for road use. In his case it is a Zodiac, running on Firestone F100 radial tyres.
What part do the tyre companies take in the overall policy Formula One and sports car racing insofar as who drives what and for whom?
R. H. Jeffrey: We do not influence overall policy in racing by using our involvement to control who drives what and for whom. If an individual or team comes to us with a proposal we will evaluate the project to decide whether we consider it to be a potential success. If we think that it has possibilities and it fits in with our overall plans, we will support it, but we do not arrange marriages. We may bless them, but we do not believe in arranging them.
There is of course the question of Motor manufacturers. This does not arise in Formula One, but in other fields—such as our involvement with British Leyland in rallies—we will do all in our power to help firms with technical and service assistance. After all, they are our customers and have a right to expect such service from us.
Mehl: We would naturally prefer that each team we sponsor have first-class drivers, and of course whether or not you sponsor a team is associated with whether or not they have a first-class driver. There are certainly only six or eight drivers around who you can count on to win races in Formula One.
From our point of view, the Brabham team is established and we will continue to support Jack as a first-class driver: we feel that he is capable of beating Jochen Rindt or Jackie Stewart on many occasions. We would like to have Rindt or Stewart driving on the Brabham team. We discussed this and Jack was certainly in favour of this, but financially it was impossible to accomplish.
Our second team is also rather established: McLaren Racing is Denny and Bruce. At one time Bruce talked of replacing himself with another driver, and many people were discussed. But good drivers resist being on a team with another good driver, it often creates problems, and of course they prefer to be number one. Denny is number one on the McLaren team and in my opinion he’s the most under-rated of all the Formula One drivers—he’s extremely capable. He rarely has a bad race and is tremendously consistent.
Our other team this year is the Matra team. We tried to contact other drivers, but they were unable to decide, either due to lack of faith in Matra’s new V12, or for various other things. We have a very good working relationship with our teams, and when they consider a driver or when they think about changing drivers they talk to us about it because they respect our opinion over who would be the best or whether we have any objection to this driver or that. This year it’s not really a factor because everything’s rather stable.
Martin:Raymond C. Firestone issued a policy document in October of 1965 in which he said that the future of the Firestone Racing Division was to sell tyres, pay prize money, develop a competitive tyre and offer sales and technical service at the race tracks. At that time we had existing contracts, made prior to the policy change, which we are still honouring. What we have left is Team Lotus and Rob Walker, but even in these cases we wrote the contract with the team, not with the drivers, so the tie-up is with the teams to use Firestone tyres. The case of Mario Andretti is based on the older type of contract and will shortly be running out.
Our new policy is to work with the teams, to have available a car and driver for testing, and to have a competitive tyre. The teams have to buy our tyres, based on their competitiveness, and they race for prize money. Thus, in this area, we have never said who will drive what and for whom.
What is the next likely move in the tyrefield with regards to safety?
Mills: This is a subject to which we were giving some, thought even before recent publicity and we have not only evolved the first safety stud retainer but have also rested it during tyre tests in South Africa. We took the first patent out last May and several others since which have been put to different companies manufacturing wheels. This has treated a great deal of interest: all we can do is recommend that it be adopted.
Mehl: I don’t mean to sound complacent, however, Goodyear did not encounter safety problems during 1969. We had the occasion when the tyre moved on the wheel due to acceleration or braking, putting it out of balance, but we corrected this by changing either the tyre or the wheel or by increasing inflation pressure. We solved the problem and refused to operate at any time when we were concerned at the safety aspect.
Punctures are unavoidable in many instances: the only way to make a tyre that will not puncture is to make a big heavy 10-ply tyre. You can add such features, as the inner safety tyres which are mandatory in NASCAR, but on any single-seater like an Indianapolis or Formula One car, they certainly adversely affect its overall speed and performance because of the extra weight.
Three or four years ago we ran a few cars at Indianapolis with inner safety tyres. These were not the top drivers because the top men were not willing to sacrifice the speed. The inner tyre adds maybe three pounds to each front wheel and four pounds to the rear, so the only way to make them acceptable is to make them mandatory, as in stock car racing. The inner tyre also offers many service problems. You maintain its stability by a differential in pressure between the inner and outer tyres, so valves are a tremendous problem and each time you design a new tyre you must design a new inner safety wheel. This increases expense—which is not the main problem—but the flexibility of the alternatives you can offer to the teams is vastly reduced with this type of tyre. I don’t think it has a place in Grand Prix races of 200 miles: I think we make tyres safer by offering more traction.
Martin: When you manufacture a racing tyre you certify your materials and have a high quality standard in making that tyre, but it’s very hard to get a competitive tyre and make it foolproof. Now we have a safety “tyre within a tyre”, giving the whole in effect two air chambers, but the weight of the inner diaphragm makes the driver feel that he’s got twice the load out there, and he doesn’t like it. In American stock car racing the safety tyre is mandatory: if it wasn’t, the drivers wouldn’t use it, for it slows down the car and makes it harder to drive because of the extra weight, which is only approximately three to four pounds extra.
As for the tyre coming off the wheel when punctured, there’s been some discussion with Lotus about putting up into the wheel a stud which goes up next to or into the bead itself to hold it from slipping off the ledge when there’s no air pressure to hold it there. Previously all that held it there was the pressure within the tyre and the bead compression. We’ve done some other experimenting, and we feel that one way to stop the tyre slipping off the rim and also to increase its coefficient of friction is to sandblast that area where the bead itself sits on the wheel.
The biggest development in our area which was also practical and increased the safety of tyres was the introduction to racing of the tubeless tyre. It used to be that the rules were actually against this, but an old demonstration in favour of tubeless which rubber companies still talk about is to take two inflated baloons and put a piece of Scotch tape on one of them. If you stick a pin in the unprotected baloon it’s going to blow up, but if you stick the pin through the Scotch tape on the other baloon, it will leak air. This is the same thing we’re talking about in a tubeless tyre. You can physically puncture it and it won’t explode like it can with a tube inside it. You’ve therefore got a safer tyre and less weight too.
What lies behind the current trend to 13-inch wheels and did the impetus come from the car makers or the tyre companies?
Mills: Matra and Dunlop had such a close working relationship that we decided 13-inch was the best approach. We pioneered the idea, although Ferrari had already started with 13-inch fronts—for different reasons. The idea came about in association with Matra.
All the rear, 13-inch wheels are a possibility which we shall all have to assess: it’s difficult to-ask a pint-sized tyre to do a quart-sized job. However, the new BRM is committed to 13-inch wheels and Jean-Pierre Beltoise tried them on the rear of a Matra MS80 at Mexico City.
Mehl: It appears that we have reached something of a standstill on improvements in 15-inch. For example, all three tyre constructors have wider tyres available in 15-inch than we’re actually racing with on Formula One cars. For Can-Am racing, Goodyear and Firestone for sure had 16 and 17 inches of tread width available.
Having reached the apparent optimum in tread width, it’s natural to start looking for something new, different and radical. The first impression was to go 13-inch—it works well in Formula Two—the Formula One suspensions are highly sophisticated now and the car constructors are beginning to get worried about tyre aerodynamics. The biggest wind resistance on an open-wheeler now is the presence of those two big front tyres, so anything you do to reduce frontal area will improve performance.
We’ve now learned to put brakes inboard, so 13-inch wheels are a practical proposition and most people are going to try a 13-inch.
It’s much the same as when somebody announced they were making a four-wheel-drive car and three other people followed suit. Why did they plough in all that money and expense ?—the answer is that if there’s a chance that the innovation works—and that they might have to race at a disadvantage—they’ve got to gamble.
There’s no way you can go into the 1975 without having highly developed 13-inch tyres for Formula One cars: We’ve tested them and they don’t offer fantastic improvements: they’re lighter and you should be able to use smaller brakes because you’ve got a smaller mass to stop.
Martin: I’m pretty sure that the first 13-inch wheel used in Formula One was with Ferrari, and this was in the latter part of 1968. Ferrari used 13-inch throughout 1969 and the other teams wanted to use it. In this instance, the impetus for the introduction of the tyre came from Ferrari. In the case of 13-inch rear tyres, test work will have to be done to evaluate whether or not the performance is there.
Why is there a tendency for one make of tyre to stand out on one circuit rather than another?
Mills: Obviously the circuits differ greatly, the requirements for Spa or Monza being quite different from those for Monaco, to give an extreme example. There are so many variables in designing a racing tyre which can affect performance, for instance the reaction of the tyre compound, pattern and casing to one type of road surface or corner. This of course is inevitable, but we have very sophisticated techniques for assessing tyre performance and to some extent you can tell in advance.
Mehl: Looking at the end of the 1969 season, let’s start with Monza, which is not a “tyre” circuit. Our latest compound, G20, went to Canada for the following race in the series, and I think it was marginal. Perhaps it was a bit too soft (we experienced some “rolling”). At Watkins Glen the cold weather did not help its performance, but the McLarens anyway had some bad problems while the Brabhams ran into practice bothers and didn’t get to qualify well.
However, I must agree that G20 worked well at Mexico City. At that circuit the four cars using our tyres were in first-class peak condition and the drivers were full of confidence. The end result of this set of circumstances is that the tyre looks good. The tyre was good and it certainly had an advantage in that race. But you must have everything going for you to get a result like that—and we finished 1, 2, 3.
Having a tyre like G20 available increases the confidence of our teams: it makes them work harder and you get even better preparation than normally.
Martin: Any given surface has its own particular coefficient of friction. The compounding of the tyre (and the type of construction that goes with it) takes advantage of this coefficient to give the tyre its superiority. Temperature is another critical thing: you can goof up and be running too hot or too cold, that also affects the running of the tyre. There are lots of variables besides these which give one tyre an advantage.
What feedback is there from racing into road tyres?
Mills: This can be covered under several heads illustrating the different trains:
1. The philosophy of wide flat road tyres (of which the latest “60-series” Dunlop developed for the Lotus Elan 2 is a good example) has been applied to improve the grip, handling and safety characteristics of road tyres.
2. The techniques used to get something for nothing, that is better grip, stability and wear, as in the D75 “groundhog”. This is achieved by curving the tyre in the mould (“reverse crown”) and blowing it up to its correct shape.
3. Detailed design features such as broad centre channels to improve wet road performance.
4. New materials.
5. The sharpening of creative ability at design level. Changes are required so quickly in racing that personnel become more adept when they work on road tyres after their experience with the Racing Division.
Mehl: There are several concepts developed in racing which have been applied to today’s road tyres, for example wet traction. The lessons we’ve learned in racing are being given a road application: for instance in tread compounds, the low profile concept and reverse moulding, all of them innovated in racing.
Tubeless tyres have made their mark in racing and so far as we’re concerned, there’s the possibility of warning the driver that he’s got a puncture. This is because tubeless tyres lose air slowly and it has been known even for the driver not to react to air loss.
Martin: Being on the racing side, I feel that the feedback is far too slow. You can look at the new tyres coming along for production cars: they’re lower in section height tyres which give better handling and performance, as we’ve found over a period of years in racing. But there’s always the problem with the car manufacturers of adapting to these new lower wider production tyres that require suspension changes. In racing, we can make these adjustments very hurriedly in order to adapt to the increased performance given by the new lower tyres available to us.
There could be a good deal more co-operation between the manufacturers of tyres and cars to develop an exciting new product, a good example being the advertising centred around the Jaguar XJ6.
What is your attitude towards the use of a road tyre, particularly a radial, in a racing application?
Mills: I would say that we design road tyres with specific properties and they are built to a given cost. A racing tyre is built differently to do a different job. For instance, a road tyre spends 2% of its time going round corners at low speed, whereas a racing tyre spends 40% of its time cornering very hard indeed. Why race on a road tyre when there is a racing tyre available ?—you don’t get the same performance.
Costs are not directly comparable, because to be competitive in Formula Ford (which requires road tyres) we understand that between 50% and 60% of the tread is buffed off the tyre before it is used anyway. And in Sweden the government of the country demands that racing tyres be used on the cars.
Mehl: I think that some of the latest low aspect ratio (“70 series”) tyres might have sufficient safety and performance to be used in certain forms of club racing. In general, though, there is a strong possibility that you would have failures with normal passenger tyres.
I’ve seen people run Mustangs, etc., on Goodyear polyglas “Wide Boots” in Canada and they seemed to be reasonably safe. If the tyre companies could be required to supply tyres for a given type of racing (e.g. Formula Ford) there would be no safety problems there: Formula Ford has in fact turned into a little tyre war of its own.
The tyre is actually the only part of the car which touches the ground and if competitive people think they can get some advantage with a tyre, they’ll do it. But who would know—or be able to find out—if we took a regular passenger tyre and put G20 into it?—it’s very difficult to tell, the difference is virtually undetectible. We say quite straight forwardly that our rally tyre is a passenger tyre with a racing compound in it: we sacrifice wear and increase cost, but this is a good development.
Martin: The purpose here (as in Formula Ford or the newly introduced Formula 100) was mainly to keep the cost of the tyres at the minimum possible level. The cost differential between a passenger tyre and our racing tyres anyway is fairly high: it’s a multiple at at least five. A passenger tyre costs about £5 and a racing tyre about £25.
In these two formulae the speed of the car is less, so its requirements are less. We build road tyres which are supposed to do 130 m.p.h. or more: put them on a lightweight formula car and you can increase their capacity because load is what you’re designing against. So I think it’s a good idea because prices are low and it offers the manufacturer a tremendous opportunity to advertise his product relative to those who follow racing.
What is the cost of a racing tyre?
Mills: We are always prepared to talk to the racing clubman whom we have supported for so long and there is available a used price list which sets out just how much he will have to pay for his tyres. Just as an example, a new set of Formula Three tyres, of a type which was virtually essential to win at the beginning of 1968, cost about £55, from which there was the possibility in some cases of a discount. The racing tyre department is self-supporting, but sales are handled directly from here or through approved distributors, who must buy them at the same price as the individual customer.
Mehl: We are selling our tyres at any price from £16 to £24: we sell them, not to make a profit, but to increase the use of Goodyear from an image standpoint. We’re selling these tyres for what it costs us to make them and there’s no profit built into the price structure.
Martin: Our production unit is very small relative to our other units, so our unit cost—just in manufacturing terms—is about £25. This does not take into account the expense which has gone into developing the tyre or the sales and servicing expense which is put into servicing at the track. It’s just a manufacturing cost to cover the materials, labour and equipment used to produce it.
The Racing Department itself is what Firestone calls a ‘net expense” and our goal, instead of increasing this at the rate it was going (which was terrible) is to hold it to a normal growth net expense which is feasible to live with.
How many racing tyres do you sell per year?
Mills: Our present sales are running at the level of 50,000 per year a figure which we expect to rise because the worldwide interest in racing is rising, notably the interest in Formula Ford, for which we supply racing tyres in the narrow size necessary on the standard wheels.
The market for Dunlop tyres abroad includes a substantial number in the USA and other varied destinations such as Poland, Czechoslovakia, Guatemala, Argentina and even the USSR.
Mehl: We propose to double our capacity in 1970 and are presently making 300 tyres per week (more than 15,000 per year). The United Kingdom is the toughest market there is for racing tyres, but we export in the proportion of four home sales for every one abroad. Demand can vary and we received floods of letters following the success of G20.
Martin: We’re hoping that in 1970 we can double our British production output, which means going from 7,000 to about 14,000 tyres per year.