Heard a loud rumbling noise yesterday comming from the tunnel. Melted all the snow and ice out of it and noticed the two idler wheels in the middle were shot. Rubber broke off...after further inspection of the other 4 wheels the rubber is all cracked so i have ordered 6 new ones. My question is this common? Sled had 3800 miles on it and is studded. Dealer studded it and there are studs right where the idler wheels ride in the track. Could this be the cause or does anyone think they were just at the end of there life?