The way I heard the joke was that it was a man named Dunlop who came into buy a kilt, and the clerk on duty sold him a Macintyre tartan kilt. When the manager asked the clerk why he sold a Macintyre kilt to a Dunlop, the clerk replied:

"Well, sir, the Dunlops have been makin' tyres for years!" :mrgreen:

Cheers,

T.