i use slime on my mtn bike b/c i hate changing tires in the trail. On the road, I just carry a spare tube. I rarely have flats b/c i watch where i am going. In the trails the thorns seem to cause flats and you cant avoid them. BTW, i use slime tubes and not the squeeze tube to put in a regular inner tube. That stuff is messy. Inspect the tires on you roadie before you ride.