I have some friends who say they'd like to ride with me, but they have really cheap dual suspension bikes from Target. I had one for about two weeks and on some paper that came with it, it said something like 'not for actual use on mountains/trails'. I don't want to offend them and ask them if their 'cheap' bikes can really go on trails, but I'd like to invite them and I want them to be safe! You think these bikes would be safe? It's a pretty rough trail- huge gnarly tree roots, sudden turns with trees in the middle of the trail, steep hills WITH gnarly tree roots, etc.