Is there any wood that will have stength and that will not crack ouder pressure and tention?
You're gonna hafta be a bit more specific.
The wood on my skate board ramp i have is starting to crack a little where there probly was a gap between the under sub layer of ply wood is there wood that will not crack like that and still be smooth and hard?
Oh, so you're not just looking for "wood," you're looking for plywood that is hard enough to withstand the impact of the skate board, strong enough not to break, yet flexible enough to bend into the curve, not to mention moisture-tolerant. Baltic birch comes to mind, though it's a specialty product that Lowes/HD won't have. If you can keep it dry, 1/4" masonite might work.
I have heard that masanite will bubble and fall apart
No, there is not a wood that will work on ramps or half pipes. Look at the link I included below----this is what will work the best.
Here is a link that might be useful: Skatelite
I have seen skatelite before and it is expencive or at least to much for my project i was looking for some thing that is less money the material dose not have to be that flexable its a mini ramp and there is no rool ins
The problem is that skateboard wheels are very small, meaning with a rider on the board, there is an emormous amount of pressure exerted on the skating surface.
I have seen ramps made by using 1/4" plywood---a couple of layers at a time. The top layer lasted less than a year with moderate use. The kids had to replace the top layer two or three times a year.
I'm with Handymac, kyle. The appropriate choice depends on more than your budget; it depends on how long you expect the result to last. You've already learned that lauan plywood is a poor choice. Other home-center materials might be better, but you'll have to think of even the best of them as temporary/disposable materials. Materials that might be durable enough to think of as permanent will be special-order items, and will be pricier. Reconcile yourself to either spending more or redoing the job periodically.
just my own two cents
do it in layers, the wooden ramps you see at the x games are wood, but they are very large thick sheets that are sometimes covered with a marine grade polyurethane
Look at the link I included below---it describes how the builder built the X Game ramps----top layer is Skatelite, not plywood!
Here is a link that might be useful: X Game ramp construction