My fixed gear Trek T1 developed bad non-drive crank arm play (about 5-6mm). It has stock Bontrager crankest an d splined BB. The BB appears to be fine, The arm had play on BB spline after I took off bolt; so I am wondering if the arm splines are worn off and I need new arm? I bought the bike used, it apparently has seen hard use. Quite honestly I don't like the stock crankset, would rather replace the whole thing, but not sure what I need to buy. Thank you.