Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Pain in the neck!

My 3-year-old son has a ton of the Thomas vehicles and loves them, but Thumper is poorly designed. The treads fall off the wheels right away, and you will be spending your time replacing them every 5 minutes! I'm not sure why the previous reviewer gave this item 5 stars while complaining about the treads coming off. This is my major complaint with Thumper.