how a tyre works

Classic Car Weekly (UK) - - Living With Classic -

1 Beaded edge tyres

Nearly all au­to­mo­tive tyres con­tain a steel bead within the con­tact point with the wheel rim. But early pneu­matic car tyres fea­tured an ad­di­tional moulded area which sat in­side the shape of cross­sec­tional shape of the rim. This was an at­tempt to over­come the ten­dency for tyres to leave rims, un­der the in­flu­ence of com­pressed air pres­sure and cen­trifu­gal force.

2 Crossply

Still with steel beads at the rim edge, but now fit­ting onto wheels with wells, less­en­ing the ten­dency to throw off the tyre, con­struc­tion fea­tured lay­ers or ‘plies’ stretch­ing from bead to bead. This gave the tyre walls a rigid con­struc­tion of­fer­ing good di­rec­tional con­trol. The lack of side­wall ‘give’ on cor­ner­ing led to easy loss of grip on en­thu­si­as­tic cor­ner­ing.

3 Ra­dial

The con­struc­tion of ra­dial tyres rev­o­lu­tionised grip on cor­ner­ing and at speed, keep­ing a greater tread area in con­tact on the road when un­der the in­flu­ence of side­ways forces, al­though the softer walls also led to heav­ier steer­ing char­ac­ter­is­tics, es­pe­cially when retro-fit­ted to older cars. Here, flex­i­ble ‘car­cass’ plies ex­tend from bead to bead, with steel re­in­forced ‘ra­dial’ plies in place around the tread and top shoul­der ar­eas of the tyre.

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.