up here in new england the riding season is quickly coming to an end, I have already started with the winter mods. I recently bought, and installed a renthal 43 tooth rear sprocket, functions like it should but i wanted more from it so i bought a mathcing renthal 15 tooth front. I haven't installed the front yet. This being said, i took a close look at the 15tooth and engraved on it besides "renthal 15", is also a "520" and a "315U" i have no idea what the 315U could mean, i don't think its length but i could be mistaken as I am a newb. So is this telling me i need to run a 520 chain right now? or am i good with my stock 530 for the time being? i want to finish out the season on my old chain but i also want to install the 15 tooth front. ahhhh. what should I do??...pretty though, isn't it?