Their puncture resistant, not puncture proof. You also have a tube inside the tire than can develop a leak even if nothing gets through the tire.
Wal-mart has Bell Airtight brand tubes costing more than normal tubes. These tubes feature rubber three times the thickness of standard tubes. They consequently weight three times more. I use them on my touring bike currently fitted with Panaracer CTX 737 700c X 37 tires. They have been under two other pairs of tires over the last two years and no flats encountered. They do not need airing up every morning and I can do an entire tour of up to two weeks and not add air the entire time. It takes about a month for them to lose 5 lbs. so there well worth the added weight in my opinion (for touring). I would still take a patch kit, extra tube, and tools as there nothing worse than walking a bike, especially when your days away from home or a bike shop.

' think I'm getting those too. Thanks!

schwalbe is better... but more costly.

I always had a heck of a time getting Kendas to mount correctly on the rim. Once they were mounted they were good for a couple of thousand miles. But its not a brand I equate with quality. Though if I'm poor at the moment(as I often have been) I'll buy them.

I bought the 27" Bell tires from Wallmart and put them on. As I was pumping, at about 75 PSI, I watched the bead peel off the rim. The tube bulged out for about 1 second before it blew. Dust and debris flew, and my ears were ringing. Thinking I messed I tried again, very carefully, with the same result. After this I inspected the bead and found an area were the lip that catches the rim wasn't raised as much as the rest of the tire. I eventually got the tires to seat by pumping them up 10psi at a time and leting them sit for a while. I never did ride on them much since I completely disassembled the bike and am now in the process of painting and making somthing (1x9 maybe) out of it.

I've never really had a hard time with mounting Kendas - although I generally use these cheap tires, so maybe I just don't know any better. I find them a little stiff and impossible to mount without a couple of sturdy levers, however. I wouldn't equate them with quality either.

Since the local Canadian Tire sells Kendas for $11 and the local LBS sells a better quality tire for $14, I'm gonna spend the extra $3 a wheel and see how they compare...