I was going to replace my MS290s bar, drum and chain. I am looking through Baileys catalog and am perplexed at what to order. The ArborMax combo seems almost to cheap. The drum they show is a "RIM & Drum system" which has a sliding sleeve. What is the advantage of this? Mine currently looks like just a spur sprocket. My current bar is grooved deep and the sprocket tip is worn pointed. The drum is worn in deep as well. So what would you replace this with? I can locally buy all the parts but just the bar alone is $50 plus. I want to get something comparable in quality to the Stihl parts. Also thinking about getting the Moistec moisture meter. How does one figure the pitch of chain and drive links short of counting them out? Also I would like to run non safety chain if there is an advantage. My chains are stihl as well and the bar is so worn that all I can read is 45 cm and 1.6mm/0.063"