ok so i got home from work yesterday, been gone 4 weeks, been about a month since i last rode. Pull the bike out today, and my tires are blue. Not the whole tire, but jsut hte most used part of them, near the centers, and about 1" from my stripes. Rubber felt good, tires only have 1444km on them, and pressure was fine. Does this meen anything? I went for a ride just now, and they are back to black. Not really worried about them, just curious, whats it mean?