Not sure if this is the right place to ask this, but I'm looking for advice on a bike. I live in Pittsburgh, PA, so not the smoothest roads or sidewalks. I'm currently riding my 26" Walmart mountain bike but I need a 29", and that's about all I know. With all the potholes and such, I feel like I need the thick tires of a mountain bike, and some kind of suspension, but I don't know. I see people with thin tires all the time but I feel like that would be risky? I'd like to spend less than $300, as I'm on a budget and only needing something to last at least a few years. Are used bikes in my range worth it?