Radial tyre
The modern tyre construction with radially arranged carcass cords and a stabilising belt. Introduced from the 1940s, it displaced the cross-ply – more grip, less wear.
In a radial tyre the carcass cords run radially, at 90 degrees to the direction of travel, from bead to bead; above them a belt of steel or textile plies stabilises the tread. Michelin patented the construction in 1946 and brought it to series production with the Michelin X – over the following decades it displaced the cross-ply almost completely.
The advantages explain its triumph: because sidewall and tread work independently, the contact patch stays flat and large even when cornering. That brings noticeably more cornering grip and wet-weather adhesion, more precise steering, lower rolling resistance and far higher mileages. The construction is recognisable by the 'R' in the size marking, for example 165 R 15.
For classic cars the radial is the comfortable everyday choice – many classics can be converted with suitable approvals, often even with period-styled radials from well-known makers. Still worth observing: never mix constructions on the same axle, check rim widths and approvals – and anyone wanting to appear period-correct at concours or strictly historic events stays on cross-plies.
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Related terms
Regularity rally
Classic-car motorsport where precision counts, not speed: hold prescribed average speeds and target times as exactly as possible.
Odometer
The distance counter built into every vehicle and the simplest form of distance recorder. Usually too imprecise for rally navigation – the more accurate tripmeter is used for that.
H-Kennzeichen
Germany's official historic-vehicle plate with an ‘H’ for cars 30+ years old – full everyday use, flat vehicle tax, free access to low-emission zones.