Bicycle Mechanics - Help - Tires always pop!

I love to ride on an off-road, usually trips of 1-3 miles at a time. I weigh 200 lbs and do not 'dog' my bikes out- I ride responsibly. BUT my back tires go flat ALL THE TIME. This is a major nuisance so I'm looking to buy a nice bike that rides well, is comfortable, and has lowered chances of popping a back tire. If that means shocks, or some special tire types, I'm willing to pay a little more for a sturdier/hardier bicycle. Any help would be very appreciated. Thanks.

Tires don't normally pop. What air pressure are you inflating to? 200 pounds is NOT heavy enough to require any unusual tire configuration. You also say you ride off-road - what tire size are you riding (the size should be molded into the side of the tire - something like 700x26c or 26x1.75.

Then I must be using something other than tires on my bikes because they go flat when I ride them. The only thing I can think of offhand is that the rubber must be dry-rotting because I seldom use a new bike or tire. I know nothing about bike or tire types, which is why I'm here. I'm really looking for a recommendation on buying a new bike.

So far these look decent, but I saw some with suspension somewhere. How useful is suspension on such a bike?

http://bikecatalog.bikeworld.com/ahybrid.php

What are you riding now? that'll help us help you with what you specifically need to change to avoid this annoying flat problem.

I'm riding an old mountain bike. The Trek fitness bike is looking good->

http://www2.trekbikes.com/bikes/subcategory.php?c=4&s=17

maybe its the are you are riding in? does it happen a lot in the same place? has there been a rash of people getting flats in that area?

from the list of bikes, none are mountain bikes. hybrid and comfort bikes might take you onto some light trail riding, but not really offroad. without knowing what kind of riding you really want to do, its hard to say how well these bikes will perform. as for the tires going flat, just about any new tire should be fine.

I love to ride on an off-road, usually trips of 1-3 miles at a time. I weigh 200 lbs and do not 'dog' my bikes out- I ride responsibly. BUT my back tires pop ALL THE TIME. This is a major nuisance so I'm looking to buy a nice bike that rides well, is comfortable, and has lowered chances of popping a back tire. If that means shocks, or some special tire types, I'm willing to pay a little more for a sturdier/hardier bicycle. Any help would be very appreciated. Thanks.

A better bike is always great, but I suspect you have a different problem.

From what you describe, I suspect that you have something pointy INSIDE the casing of your rear tire. It could be thorn that you picked up a while ago and never found. Carefully run your fingers along the inside of the tire casing. If there is anything "pointy" in there it has to be removed. It it breaks off, it needs to be sanded down.

Now, you describe your tires as "popping". Basically, they're exploding. Typically tubes do this when there is some area that allows them to "bulge" outside of the tire casing. At some point the bulge gets too much for the tube to handle. There is a couple different ways this can happen. One is that the tire is sitting outside of the tire bead. Under this situation the tube can sit relatively uninflated between the bead and rim wall. Than you may shift the bike "just so" and all the sudden it inflates, than the bead cuts it and BOOM.

If you're using tubes that have an uninflated volume larger than the tire casing, this is easy to do. Personally, I use downhill tube on 2.35" tires because they are really hard to flat. I have to VERY carefully stuff that tire and then make sure that there is no tube between the bead and the rim wall. A couple of weeks ago, I set a tube inflated, than as I was testing the wheel by pressing down on it the tube spontaneously popped out of the tire and the entire bead become un-seated.

I've saved the best for last. Do you have a rim-strip? If not, you need to put one one. Cloth is better. The rim strip prevents the tire from expanding into the spoke holes. Basically the tube forms blisters in the spoke wholes without tape. If the spoke heads sit above the nipples and you have not rim strip, the tube can effectively be "popped" by the spoke heads.

I think 'pop' was the wrong word to use. They're just going flat. Thanks for the tips.

I'm with willtsmith_nwi on this one. I suspect you've got some debris or sharp-point inside your tyre or rim somewhere that's causing a puncture to your tube. Take yoru tyre off and rub your finger lightly all along the entire inner surface and feel for a thorn or piece of glass. Also feel inside the rim itself. Then inspect the rim-strip and make sure it covers all the spoke-holes. If it's a rubber rim-strip, throw it away and get a stiff plastic one or use packing-tape (with the thread-fibres embedded).

The other thing could be that you're not using enough pressure. This allows the tyre to compress fully over bumps and the rim-edge will pinch the tube and cut it resulting in twin-hole "snake bites". If you've got 26x1.95" MTB tyres, make sure you've got about 50-60psi in them for street use.

Keep your eyes down on the road just ahead of the bike when riding, 50-75ft ahead should do. A lot of people don't look at where they're going. Looking at the horizon may be scenic, but you're not gonna reach that spot for 2-3 hours. Rocks and potholes will hit you in 1-2 seconds and cause all sorts of grief, don't hit those...

2 very common causes for chronic flats.

1. No rim tape... this is cheap thick tape that goes on inside of rim. Prevents spokes from digging into tube.
2. Presta valves not being closed. If your tires use presta, you have to screw in a little nut after you inflate them. (have to unscrew nut before you inflats) -- You'll know this is the problem if your tires go flat, but you just have to inflate them again for them to be full.

Uh...question: Are you fixing the flat tire, or just pumping more air into them?

You could have a slow leak.