I bought a new Exmark 36 Metro back in March of this year. Recently (within the last 6 weeks) I noticed that the mower was starting to scalp in areas it had never scalped before. So I checked the back tires. They had enough air. Then I switched blades. Still scalping. Today I said "enough is enough" and added a spacer to the front casters and the scalping disappeared (suprise). Then I brought the machine home, removed the extra spacer and put a tape measure to the blades and low and behold, it was a half inch lower than the other machines. Hmmm... I put a straight edge on the deck, it was nice and straight. I checked for broken welds or missing bolts. Everything appeared to be in order. Then I put a tire pressure gauge on the front caster tires. One had 5 pounds and the other one had 15 pounds. Then I filled them up to the factory recommended 25 pounds and checked the blade height and wa-la, I got my half inch back. You're probably wondering "Why didn't this dumb-ass check the front tires as part of weekly maintenance?". Well the tires are filled with sealent from the factory and dummy me thought that they might hold air for a while. I know better now.