It comes with 32s, so the tires are pretty big already. Really it rides like a tank even unloaded. I am a big guy, so maybe that changes some things, but I'm just comparing it to other bikes. In fact, I also have a 1971 Raleigh Sports. It has wider tires, but there is a problem with the steering. It always turns to the right immediately if I let go of the handlebar. I don't know a lot about bikes like many of you do, so I don't know what is causing it. When I hold the handlebar it doesn't really cause a problem, but I would like to figure it out.