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

This type of stand (there are others on the market) has a number of inherent flaws that make it inadvisable for a mountain bike. Besides putting pressure on the spokes, it is too low to hold the weight of a mountain bike, the support arms can hit the derailleur and throw it out of alignment, and the movable side (adjustable for tire width) usually moves over a couple of notches when you take the bike out. Furthermore, as they are made of plastic, they are very light and the footprint is not wide enough to keep the entire unit from tipping over with your bike. Also if you set it tight enough to hold the wheel straight it doesn't release when you try to pull the bike out and you have to push it off with your foot. I own a Saris version of this stand and have had nothing but trouble with it. My bike has fallen a number of times.