i had that on my low profiles mate.... get it checked before it gets worse mate coz mine messed about with the tire pressure, the pressure decreases and as your driving and the tyre deflates really slowly so there is more pressure on the sidewall and it eventually wears down and cracks.mine messed up completely and the tyre ended up completely tearing... lucky i didnt have a blow out really, but ye id say get it checked out.
now i got the same kinda problem on my new tyres ( 2nd hand wheels = tyres till i get my old ones sorted ) but its not on the side wall, runs horizontally across the tire tread, tyres are geting old though so mite just be general wear and tear.
anyways hope you get it figured out.:approve: