The Dunlop K81 TT100 is a motorcycle tyre[1] thought to be an "obligatory" performance upgrade [2] and a tyre of choice[3] with sporting street motorcyclists during the late 1960s and 1970s[4] due to their shape and relatively sticky compound.[5]
History
Originally introduced in early 1968 as the Roadmaster K81 rear tyre[6] by Dunlop Rubber Co. Ltd,[7] the tyre was renamed "TT100" because it was the first production tyre to reach a lap speed of 100 mph over the Isle of Man TT race course when Malcolm Uphill rode his worksThruxton Bonneville to victory in 1969 with a fastest lap of 100.37 mph during the 750 cc class production race.[8][9][10] The feat was repeated in 1971 when Ray Pickrell averaged 100.01 mph on a Triumph TridentSlippery Sam replica, a modified version of the motorcycle the tyre was designed for.[11] The tyres were standard fitment on production models of BSA and Triumphtriple motorcycles.[12]
Originally called in some countries the "Dunlop Roadmaster K81 Trigonic Tyre" and developed from Dunlop's racing background,[13] TT100s were first made in England, and then later reintroduced from Japan,.[1] The tyres featured a unique "Trigonic", or triangular, profile which provided ample outstanding grip for the day,[14] and an identical tread pattern to front and rear instead of the usual circumferentially ribbed front tyre of the day.[3] Considered a "super tyre",[15] it continues to be made utilising the latest technologies and materials for improved performance.
^Motor Cyclist Illustrated, May, 1968. p.53 In Brief. "Dunlop have introduced two new racing tyres and a new road tyre intended for high performance machines. Based on the famed 'triangulars' the KR83 rear and KR84 front are designed to cope with the vastly increased performance of machines like the 500 cc Honda and MV racers. Still of triangular pattern, they have a lower profile than the earlier pattern so that there is 20% more rubber in contact with the road. The Roadmaster K81 is the first road tyre to be based on the triangular design: it will increase the safety margin, when cornering especially, for race-minded owners of fast 650s". Accessed 23 March 2015
^Motorcycle Mechanics, June 1973, Dunlop full page advert, p.6 Every time they race you win. "Tyres like the K70, Ribbed and the fabulous K81, re-named the TT100 after lapping the TT course at over 100 mph on a production machine". Accessed 23 March 2015
^Classic superbikes from around the world Mac McDiarmid. Parragon, 1 Jan 1995
^Triumph: A Century of Passion and Power. Lindsay Brooke. MotorBooks International, 5 Jan 2003
^Walneck's Classic Cycle Trader, July 2009. P.115 Dominion Enterprises
