Would a early 90s Diamondback MTB frame be okay to turn into a fixie?

[RedBike]

When things become REALLY steep the bike slows to such an extent that it no longer has the momentum to pull the cranks through the deadspot. Therefore I don't think fixed wheel allows you to climb anything you can't climb single speed. However when you are travelling quick enough to get that flywheel effect fixed wheel does seem smoother and therefore easier to climb on than singlespeed.

 

[Femto]

I can fathom that there is an advantage to the fixed wheel but yes, as you say, RedBike; if you're grinding up a 35% hill, you probably won't get any flywheel assistance. Just simply thinking about pedaling up a 35%er makes me feel faint! :-S