ESDU 71026 is the second of a group dealing with frictional and retarding forces on aircraft-type tyres. Methods are given for estimating: (i) the coefficient of friction for unyawed tyres in both braked-rotating and skidding conditions on prepared hard runway surfaces in dry and wet conditions; (ii) the limits placed on the braking force due to brake energy and torque considerations; (iii) the maximum and locked-wheel tyre-runway braking forces; (iv) the mean effective braking force developed during a period of braking, either manual or automatic. The results of much tyre-friction work carried out since the original issue have been incorporated by amendments made to the Item so that it now covers the coarser-textured surfaces and grooved surfaces. ESDU 71025, Part I of the group, describes the mechanisms by which braking forces are developed and the effects of tyres, runway surface and aircraft operational and design factors. Part III of the group, ESDU 72008, considers planing of aircraft-tyres on wet runways.