My opinion is that...My CR 80 ate one for lunch...
Really, it depends on your size, age, and what kind of riding you intend to do...how about filling out that little questionnaire for us please!? (Find it at the top of the threads in this forum).
If you're using it for road riding, I'm not sure that it'd hold up to highway speeds...
I've sat on them...and they're pretty doggone heavy too...
Ahhh! That does provide quite a bit of explanation!
For a second bike...play bike...or otherwise, I think it'd be fine...I don't know them as well, but haven't heard rotten things past that they are heavy as a brick.