Ok hears my question last week I bought a set of bontranger comfort tires for my mtb that I use as a winter commuter yesterday I was riding to work herd a pop then air leaking I made it about halfway to work when it went flat when I got to work I pulled out the tube and found a nail in it I patched the hole only to find two more that I think were a result of the nail as I pushed my bike to work so I went and bought some slime tire liners and put them in both tires (I ride through some bad parts of town at 2 and 3 in morning and the idea of a flat scares me a little) so pump my tires up ride home every things cool I ride work today great I leave work IM cutting through a parking lot and I here air so ride hard back toward work block shot cool go in look at my same tire as yesterday and it has a big slice in it the tire liner took most of it but not all now I need a new tire because you can see the tire liner from the big slice any way do you think this is just dumb luck or do I have to much air in my tires I have them at 70 psi any suggestion