Mountain Biking - bike jumps

i want to build a few jumps on the trails around my house, just for fun. im just a mtbiker, not bmx or anything, but jumps are fun as you know. well my bike is pretty crappy (from costco) and i dont know much about bikes but i guess it is a hardtail, if that means that it has only front suspension (not much though). i've jumped it off the wheelchair ramp of our front porch, which is maybe almost 3 feet. is that bad for a crappy mtbike? and i want to make some more jumps maybe around that height. i'm wondering mostly if its bad when you land on flat ground, instead of on a downhill slope.

what i mean by "bad" is, is the bike going to break soon

Frames are generally built to take a fair bit of abuse, but unless it's been especially built for jumping you'll probably wreck it eventually. Most manufacturers exclude jumping from their warranties.

Richard

Start with a small dirt mound landing to flat. Then build a landing mound, but lay a piece of plywood across both. Once you're comfortable landing all the way across, remove the plywood. Then just add more dirt to the take-off and move the landing mound further away!

Your Costco bike will eventually die! The frame material is inexpensive and thus not strong as other materials. However, learing to jump is very abusive regardless of what bike you have! Better to destroy a $200 p.o.s. bike, learn technique and then buy a decent bike once you learn to land smoothly!

Always wear a helmet, wear shin guards, ....blah, blah, blah!

You can jump any bike, its the landing thats hard. :) As stated above, start small, and think about your safety.

Yup its better to land on a downhill slope but it wont break your bike!!!!!!!!! No matter where you land unless your jump is huge like 6 feet. Dont worry how crappy your bike is it wont break. I used to have a Supercycle, very cheap no shox and i wuz doing 4 foot jumps. I still have that bike!

I'd say just practice, the more time you spend in the air the more techniques you'll pick up. It's impossible to pradict if and when a bike will break. Besides, it's great fun, so when it does break, you might want to think of a better bike for it, you never know how serious you'll get about jumping after awhile.

I went through 4 frames and a set of forks on my old Columbia MTB from the late '80s. People like me are why the cheap bike manufacturers quit offering lifetime warrenties on their cycles. Like everybody else said, there is no question if your Costco bike will eventually fail from jumping it, the question is when will it fail.