Winter Tyres

We follow our comments on radial tyres last month with some words on another type of tyre popular among enthusiasts, those which have been designed specifically for use in snow, mud and on soft ground generally. Winter tyres, or “knobblies” as they are popularly known, are mainly of cross-ply construction, although recent introductions do embody radial plies. They all have a characteristic chunky tread pattern designed to cut into soft surfaces, and consequently do not grip as well as tyres with normal treads on hard-surfaced roads. Another disadvantage is the relatively high heat generation produced by the treads. For this reason, it is generally unwise to use such tyres at high speeds, general maxima being about 80 m.p.h. for cross-ply tyres and about 90 m.p.h. for radials. A feature of the rubber quality in winter tyres is its ability to remain relatively flexible at very low temperatures.

Many winter tyres have been designed to accept tungsten-carbide studs in order to provide maximum grip on ice or hard packed snow. Studs have been in use in Sweden for a number of years, particularly for rallies and ice races, and we have the Swedes to thank for their introduction to Britain. Ideally, if studded tyres are fitted at all, they should be fitted to all four wheels, but if relatively short distances are to be covered on icy roads two on the rear driving wheels will suffice. Front-wheeldrive cars should have them on all four wheels, since two on the front only will produce marked oversteer. Fifty studs per tyre is an ordinary minimum, but many hundreds are quite common for rallying. On dry roads they are rather noisy, but are claimed to wear at a rate no faster than the tyre itself. Cost of studding a 5.20-10 tyre could be as little as 25s., but may be as much as £20 or more for competition work. They can be of two types pin and hollow ferrule.

Avon Waymaster.
A cross-ply winter tyre with recommended stud positions marked on the tread.

5.20-10 : Tubed, £5 0s. 0d. Tubeless, £5 17s. 6d.
6.40-15 : Tubed, £8 5s. 6d. Tubeless, £9 3s. 0d.

Dunlop SP.44 Weathermaster.
This combines radial construction (with fabric bracing bands) with the winter tread as used on the conventional cross-ply Weathermaster. It is available in four sizes only, but the range will soon be extended. It is suitable for studding and the recommended stud positions are marked. A competition version is available which has fewer sipes to increase the number of rubber blocks available for studding.

145-10 : Tubed, £6 4s. 6d. Tubeless, £7 2s. 0d.
185-15 : Tubed, £10 7s. 0d. No tubeless.

Firestone Town and Country.
Although this is certainly not a new tyre, we thought it worth mentioning for two reasons. Firstly it is not intended for studding and, secondly, the makers guarantee to pay the towing charges to a local garage, “without protest or argument,” of anyone who fails to keep going in snow, slush or mud using these tyres within 18 months of their date of purchase. It is of cross-ply construction.

5.20-10 Tubed, £5 0s. 0d. Tubeless, £5 17s. 6d.
6.40-15 : Tubed, £8 5s. 6d. Tubeless, £9 3s. 0d.

Goodyear Ultragrip.
This is a cross-ply winter tyre which can take studs, although the unbroken areas of tread are limited in number.

5.20-10 : Tubed, £5 0s. 0d. Tubeless, £5 17s. 6d.
6.40-15 : Tubed, £8 5s. 6d. Tubeless, £9 3s. 0d.

We hear from a reliable source that a radial-ply version of this tyre will soon be introduced. Certain cars in the R.A.C. Rally were fitted with Ultragrips which appeared to be extremely radial-like to say the least, and it may well be that the event was used as a proving ground.

India Super-Multigrip.
A winter-treaded tyre of cross-ply construction which can be studded. In fact, the makers recommend it and “clear areas” of tread are marked for studs; 104 are recommended for 5.20-10 tyres and 132 for 6.40-15. Although stud makers say that only new tyres are really suitable for studding, India claim that further studs can be fitted when the tread is one-third worn and additional clear areas are exposed by the wearing down of rubber blocks to below the level of the sipe cuts. Largest size is 5.60-15, but 6.40-15 will become available during 1966.

5.20-10 : Tubed, £5 0s. 0d. Tubeless, £5 17s. 6d.

John Bull Deep Grip. John Bull Tyres Ltd., Allington House, 136-142, Victoria Street, London.
This is a cross-ply winter tyre which is suitable for studding.

5.20-10 : Tubed, £5 0s. 0d. Tubeless, £5 17s. 6d.
6.40-15: Tubed, £8 5s. 6d. Tubeless, £9 3s. 0d.

Kelly Springfield Explorer. Kelly Springfield Tyre Co. Ltd., 1-3, Redhill Street, London, N.W.1.
A cross-ply winter tyre with a cross-slotted tread. It is only available in a limited number of sizes which does not include 5.20-10.

6.40-15: Tubed, £8 5s. 6d. Tubeless, £9 3s. 0d.

Michelin Allgrip.
This is a textile cross-ply winter tyre which can be supplied with a siped tread pattern or without sipes in the outer tread blocks to take studs. Tubed versions are only available in certain 15-in. sizes and three 13-in. sizes.

5.20-10 : Tubeless, £5 17s. 6d.
6.40-15 : Tubeless, £9 3s. 0d.

Pirelli Etna DP.34. Pirelli Ltd., 343/345, Euston Road, London N.W.1.
Unlike the familiar Cinturato, this winter tyre has a cross-ply structure. The tread is pre-moulded with sockets to facilitate studding.

5.20-10 : Tubed, £5 0s. 0d. Tubeless, £5 17s. 6d.
6.40-15 : Tubed, £8 5s. 6d. Tubeless, £9 3s. 0d.

—G. P.