What is puncturing your tires? The weight of stuff on your bike shouldn't cause punctures. It might cause a blowout if you try to carry your keel, but in that case the tire explodes, not just the tube.
If you are getting punctured by thorns, the tire liners work pretty well. It's true they won't protect the sides of the tires, but most thorn punctures are not in the sidewalls, they're in the tread. We have lots of thorns around here and I used to get punctures all the time. Since I started using tire liners I rarely get thorn punctures.
You may be getting punctures from your own spokes. There should be a strip of rubber around the inside of the wheel to protect the tube from the nib of the spoke. If it's missing they can puncture the tube.
If you're getting punctures from nails and trash in the road, you might need to go to puncture resistant or self-sealing tubes. Both of these cost more and weigh more than tire liners.
You could also be getting punctures because the tube is pinched between the rim and the tire. Underinflating the tire can cause this, as can poor tire installation technique. Try adding some baby powder inside the tire, outside the tube to decrease friction between tube and tire, and inflating the tube slightly before putting the tire back on.
Proper pressure in the tires is also important. The higher the pressure in the tire, the more it tends to deflect attacks.
Last edited by JimHawkins; 12-12-2007 at 08:55 PM.