Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Wobbly

I was so excited to find this rack on amazon. I had seen ones similar but made from wood that were going for 5 times the price (they were handmade). The package came quickly and was easy to assemble. But the the rack just doesn't seem stable , I currently have two bikes on it and the top bike continues to slide down. Both bikes are very light road bikes, so I am not sure what would be the ideal bike for this flimsy rack?