For a "period style" street tracker look, using 19" wheels front and rear, I would go with Heidenau K34 in 3.50 and 4.00x19. Sadly, they do not make these in 4.00x18, only 3.50x18. Link here: http://en.reifenwerk-heidenau.com/m...D=r4jool8cdb7pqcsdm32f7b1ej4&profil=14&pic=16