I stretched the buss out about 6.5" and I adjusted the chain the other day and started hearing the wearing noise. Got to looking today and I believe the chain is rubbing on the rubber mat thingy by the front sprocket and it's bugging the crap out of me lol. I switched from 17/43 to 16/43 with a brand new zvxm or whatever chain lol I can't remember the name ha! Is this issue I'm having normal