5.5 width wheel are designed for 180 tires, 6.0 width are designed for 190. Can you stick a 190 on a 5.5, yes. Will it affect how you bike rides and corners, yes! the arch of the tire changes, thus the contact patch changes and also affects your flickablility of the bike. Most guru's in the bike world dont advise running a 190 on a 5.5.