In Oct. 2004, I bought a Sears 5 h.p. 22" Snowthrower (made by MTD) and found one flat tire in 2006. Sears replaced the tire under warranty. Then in 2009, both tires gone flat. No warranty but to buy two new wheel assemblies (tire w/rim) at $43 each. The Sears rep told me that they sell several of them weekly and that's why they have (13) of them in stock. The new rims are of painted steel instead of the original plastic. Sears knew the plastic rims are problematic but chose not to make a recall until the warranty expires. It is a very deceptive business practice for a big box store like Sears to hide product defects info from its customer.
Please let everyone knows not to buy any snow throwers that use plastic rims. They don't adhere to their rubber tires. When they deflated, you cannot fix them.