The outer layer of rubber on the sidewall has actually only one function - to prevent damage to other, more important layers. The most important layer for safety is deeper and consists of radial rayon threads with rubber in between to prevent friction between threads.
Real damage and real problem is when external object reaches this thread layer and cuts one or more of the threads. Then the shape of the tire cannot be maintained but you get a bulge on the sidewall.
In my opinion what you have is a scraping of that outer layer. The important threads are definitely more than 3 mm deep in the sidewall and from what I can make out in the picture it doesnt appear that deep, just the outer layer, I would suggest driving it and taking a look at the tire from time to time, inspecting for bulging.
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Tuesday, February 22nd, 2011 AT 4:57 PM