You are not doing it correctly, it should be:
function GripTyre()
engineSetSurfaceProperties(9, "tyregrip", 255)
engineSetSurfaceProperties(10, "tyregrip", 255)
engineSetSurfaceProperties(11, "tyregrip", 255)
engineSetSurfaceProperties(12, "tyregrip", 255)
engineSetSurfaceProperties(13, "tyregrip", 255)
engineSetSurfaceProperties(14, "tyregrip", 255)
engineSetSurfaceProperties(15, "tyregrip", 255)
engineSetSurfaceProperties(16, "tyregrip", 255)
engineSetSurfaceProperties(17, "tyregrip", 255)
engineSetSurfaceProperties(20, "tyregrip", 255)
engineSetSurfaceProperties(80, "tyregrip", 255)
engineSetSurfaceProperties(81, "tyregrip", 255)
engineSetSurfaceProperties(82, "tyregrip", 255)
engineSetSurfaceProperties(115, "tyregrip", 255)
engineSetSurfaceProperties(116, "tyregrip", 255)
engineSetSurfaceProperties(117, "tyregrip", 255)
engineSetSurfaceProperties(118, "tyregrip", 255)
engineSetSurfaceProperties(119, "tyregrip", 255)
engineSetSurfaceProperties(120, "tyregrip", 255)
engineSetSurfaceProperties(121, "tyregrip", 255)
engineSetSurfaceProperties(122, "tyregrip", 255)
engineSetSurfaceProperties(125, "tyregrip", 255)
engineSetSurfaceProperties(146, "tyregrip", 255)
engineSetSurfaceProperties(147, "tyregrip", 255)
engineSetSurfaceProperties(148, "tyregrip", 255)
engineSetSurfaceProperties(149, "tyregrip", 255)
engineSetSurfaceProperties(150, "tyregrip", 255)
engineSetSurfaceProperties(151, "tyregrip", 255)
engineSetSurfaceProperties(152, "tyregrip", 255)
engineSetSurfaceProperties(153, "tyregrip", 255)
engineSetSurfaceProperties(160, "tyregrip", 255)
iprint("Tyre grip started")
end
addCommandHandler( "grip", GripTyre)