This is straight from Trek's company website on the Trek limited warranty page:
It says: "Lifetime" "The bicycle frame, except the fork and the Session model, for the lifetime of the original owner".
On Cannondale's warranty page it stipulates that the "frame is not covered from normal fatigue due to wear from use and age.
Trek's site does say it "does not include normal wear and tear" but nothing about fatigue or age.
And they say "best warranty in the business".
On the back page of the owners manual of the trek 6000 that I bought two years ago it also says "Frame is warranted for the lifetime of the original owner".
If you bought a trek 520 Touring bike for instance, which is a Cro-moly tig welded frame. This frame is designed to be ridden loaded for thousands upon thousands of miles. It is not uncommon for a 520 to be 20 years old and still out there touring. Seems Trek makes no stipulation between that and one of their Alum MTB frames as far as this warranty goes. so if a downtube cracks in the middle in 20 years why would they not honor this warranty? Trek's only bike frame exception is the Session model which is the Dirt Jumper Extreme hucking bike and that's obvious why they would not warranty those frames (jumping off of a 12 foot building like a crazy idiot, duh)
I have to say I am with Rushthemall on this one. Otherwise the warranty on frames means absolutely nothing.
I dont think you can fairly compare bicycle frames to Nike sneakers. But that said, like those well used Nike sneakers stink...so do individual opinions