When I had my Grace Pro frame I also replaced with metal tracking. I replaced or actually covered my poles with galvanized poles as they would bow when I tightened the quilt. The galvanized poles are fairly soft metal so I screwed them into the original aluminium poles. Worked great for me. No more bowing. Never had issues with the metal tracking either. You'd think after all these years Grace Frame Co. would change their parts to something that would last and work better.