We got a resistance trainer for Christmas and I've used it twice in the past three days. Both times the tube on the back tire has gone flat after using the trainer for half an hour. I ride a 2002 Trek 3000 with a kevlar tire on the back, if that has anything to do with the problem. Is there anything I can do to prevent a flat tire? Change the tire? Put the trainer at a different setting? Thank you for your help.

I doubt the trainer is the issue. It sounds as if you've got a leak in your tube.

Perhaps you don't have enough air in your tire, and are pinching it when you compress the tire into the trainer? I'd change the tube, pump your tire up to the normal range (on sidewall of tire), and make sure your tire is not getting too much compression when in the trainer.

Change the tube, and fill it to the recommended pressure. It should be fine.

I have owned a trainer for nearly 4 years and have used the same bicycle and same tire on it all that time. The tire loses some air over the summer when I don't use the trainer, but I pump it up the first time I'm going to use it, and it is good for the rest of the winter.

And while you are changing the tube, put the cheapest tire on you can. Why waste a good road tire on the trainer? Some lbs's sell tires just for trainers -- they are cheap and wouldn't last 20 miles in the real world but you can put thousands of miles on them on the trainer.