I once tried Mr. Tuffys on 26" mtb tires. Even with careful installation the liners wore and caused bulges on the tread. Granted, I put them into low-priced Kenda tires. But after trying various things I am sold on reinforced tires like the Marathon Pluses that I have on my hybrid or the Conti Gatorskins that I have on the road bike. They cost a bit more but they sure do last a long time, and I rarely have to fix flats. The only time I would use liners would be if I was constantly exposing my tires to sand burrs (goatheads).