My son had same problem, 13t front, don't know rear. To tight ,add link too lose. He found a place East side of Detroit for half link. Check with local shop they might be able to get one for you. As far as gearing try up or down one tooth on rear sprocket if you have them. If not I would go with half link. Might have to Google to find one. BTW, half link has roller on one end and pin on other. Not trying to be smart a$$, just trying to explain. The whole problem is that there just isn't enough adjustment on the axle.