There are two different rear wheel holders. One for Mnt. Bikes, and a narrower one for Road Bikes. I used the Mnt. Bike unit all the time, as the Velcro strap, will hold a skinny road tire in place just fine. The "Plus Size" MAXXIS 27.5 x 2.8 don't "fit", more like sitting on top, but again, with the Velcro Strap, the trie/bike is not going anywhere.