Is a conversion worth it?

Easier to buy a superseeded Giant MTB, in fact, less than a pair of wheels and a set of forks. I got a new 2004 one for a friend for $225 recently.

Converting a hybrid into a mountain bike would be a bit of a hassel (not impossible mind you, just a hassal).

Your wheels are probably 700c rather then the standard 26" wheel. Can't just slap a set of 26" wheels on your bike, as your brake studs will be incorrect in relation to the new diameter rim. Being stuck with a 700c wheel means your selection of good off-road tires is limited. Also, finding an off-road suspension fork for a 700c wheel might prove to be a real challange, I cannot think of a single company that makes one at the moment.

As the previous poster mentioned, it might be better (and possibly even cheaper) to look for a entry-level or used mountain bike. Hop on your hybrid for your commute and hop on the mountain bike when you hit the trails on the weekends. That would let you set-up your hybrid even more road specific (narrower smoother tires with higher PSI for example) without having to worry about how it will perform off road.

Cheers,
Juba

Yeah, I agree. Prolly better to just get a seperate MTB if your really into it, nothing fancy just like a simple hartail with components you can trust (around the 200 dollar range), and keep that for at least a year until your sure you wanna do this more, because your thought process changes a little once you have a couple bigger crashes, and if your still into it, get a tricked out bike.

Thanks for the thoughts guys. I've just bought some more aggressive tread tyres for my bike and will stick with that for a bit. Like you've said, if I'm still into it after a while then I'll throw some money at it.

Cheers

actually, a number of companies make suspension forks for 700cc wheels. in mountain biking they are called 29ers. marzocchi, rockshox, manitou, winwood. the problem will be that your components will blow up very quickly. your hubs, frame, rear derailleur will all blow fast. hybrids are not made for on and off road riding. that is a common mistake people make. hybrids are only strong enough to ride on the road (or gravel). they are only called hybrids because they have the comforable mountain bike geometry. so do what the others have said and go on e-bay and get a good deal on a mountain bike. after all, you can never have too many bikes!

Yeah, it's a Gary Fisher Nirvana, with motsly LX gear on it so I'm not too worried about the components going bang for a little while. I'm just taking it on easy trails at the moment but I had so much fun I was wating to figure out what was best to do in order to keep running off trail! I'll probably end up riding what I have until it breaks and then get myself a replacement. At the moment I need to keep the bike to girlfriend ratio greater than zero so no new bikes for a little while!

Grant