Instruct: Classify Amazon reviews into positive or negative sentiment
Query: not good for 20 inch bikes

We bought this for my daughter's 20 inch bike. They did not fit properly on the rear wheel bolt at first (bolt was too short for this thicker-than-average installation hardware). We were able to get them on there with a ton of work and compressing the bike frame to get them to fit on the bolt, but then we discovered that the suspension system is too springy. She falls right over because of the give in the wheels, and she's only 50 lbs. If she leaned just a bit to the right or left, the spring system bent too much and tipped her over.