Rear tire - has more weight and wears out faster.

I've definitely knocked stuff off the tire after running through debris. I can't say for sure how effective it was, but I've never gotten a flat when I've done it, and have gotten flats minutes after riding through glass or other debris and not rubbing it off.

I've certainly wiped junk out of my tires, especially stuff off to the side of the center tread that might eventually work its way in. I've also done the very fast stop with my hand jammed in the frame (once!). Only if I'm washing my bike after a ride do I look at the tires.

I am a casual rider and I ride for pleasure and fitness. For me pinching the tire gives me a good approximation of the level of pressure and if it seems a little low then I fill it up. I usually top up the pressure after every couple of days or 20 - 30 miles of riding.

I am fairly heavy, around 210 pounds, so I prefer to run my tires at max psi which is 120. What pressure would you suggest I run at and why not run at the max?

I dont check my tires even after riding through a pile of glass. In fact I might double back and scoop up some glass to chew on just to show how tough I am.

The only time I deflate and re-inflate my tires is after using CO2 and when I have an air pump handy. CO2 seems to be a smaller molecule than O2 and leaks out quicker. I will occasionally wipe my front tire down at a stop but only if I see something and usually this is due to boredom.

120 is probably fine, but some tires go higher than that, and some people just blindly pump up to max because they think more is better. There was a thread recently by a guy who pumped his tire up to the max and it blew off the rim.

I just top my tires off each day, it takes only marginally longer than checking them, and much quicker than checking them and then pumping them up.

I wipe the tyres with a damp cloth to clean them after every ride. Then check to see if anything -thorn- glass or grit is in the tyre- Easy enough to prise it out before it goes through the tyre and into the Tube.

But saturday and I had about 5 x 6mm long cuts in the front tyre. One of them had a bulge on the rubber so while at the LBS- bought a new tyre. Got home and investigated the bulge. Took the tyre off and the inner side of the carcase was damaged. the split was about 10mm long so I changed the tyre. Don't know if it would have been OK but glad I found it before I had a flat on the road.

Only ever had 4 or 5 flats on the road- but I get plenty overnight. Would have more if I didn't clean the tyres after each ride.

I have tires? Who knew...

Having a carbon atom between the two oxygens doesn't make the molecule any smaller. But it does diffuse through rubber faster. The carbon double bonds in CO2 tend to form weak temporary bonds to the hydrocarbon rubber molecules causing the CO2 to stick to the rubber. Once there it can slowly diffuse through and eventually escape to the outside surface of the tube.