ok for Juan I dont know how much any of my slightly hilly insubstantial terrain bikes weigh.

I've ridden mine to the top of (and back down) the highest mountain in England and Wales – does that make it a mountain bike? If not, then by Juan's rather silly criteria none of us own mountain bikes.

Though if it's not a mountain bike because it's not designed to be used in megavalanche (like njee I'm sure it would survive, just not so sure I would), then what am I supposed to call it, Juan?

Off road bike maybe. I used the meagavalanche as it's probably the only mountain bike (albeit downhill orientated) you people may know.
You can look for my other post on the subject, as you will find a video of the special number 2 of the round two of the 1001 sentier enduro (ronde du taïsson). Will give you an idea of what a bike should be able to cope.

Given you're still talking a complete load of tosh, I really can't be bothered searching – sorry. Anyway, I do go up and down mountains on my bike (have also ridden to the top of 10,000ft peaks in Utah on my old bike which was almost as light), hence it's a mountain bike.

Are you looking forward to watching the "off road biking" at the Olympics? I bet my bike is rather more suitable for the "off road bike orienteering" I like to do than yours is.

ok for aracer as you're damn too lazy to search.
http://www.singletrackworld.com/forum/topic/all-mountain-freeride-what-bike/page/2#post-1208530
End of page two I send the link to the vids. And then you'll tell if the course of the Olympics is likely to look like that… I don't think XC is still mountain biking (albeit maybe in scotland but then most of people walk down the slopes). It's XC end off, just racing around a muddy field.

My Orange 5AM 2008 weighs in at 29.5lbs 😀

Hmm, so your mountain biking world is limited to the "all mountain / freeride" niche? I presume from the continuous speed on the video (as much as I could bear the music for) that your riding is all downhill, in which case yours isn't a mountain bike, it's a mountain hobby horse. You do realise that mountain biking involves riding up the mountains as well as down? BTW I reckon my bike would quite happily cope with what I saw in that video – not the death by huge rocks, dropoffs and jumps I was expecting. It would be slower than yours on that, but then so would your bike if I was riding it 😉

Well two things. How do you think we get to the top of the mountain? As I said it's an enduro, so no shuttle allowed ;). Plus the bits that are fast forward are the bits that are not downhill (in this case mainly ups). I rode my HJ there 3 times (still heavier than your bike at 12.3 kg). First time it costed me a rim and a tube. Second and third time it cost me 3 tubes and another rim. We found the only way you could ride a HT down there (after riding it for 70 minutes uphill) was to fit DH wheels.

But my bike isn't a HT. I'm still curious why you think it's so incapable just because it's light.