Building a jump...

I know how to build BMX jumps.

I have a few down here in Point Loma.

Pics to follow.

I use to work for a trackbuilder in CA. You would be surprised not that much math/calculations went into it, not as technical as you think. But then again he knew what he wanted from decades of riding and years of building. this link if the best i have found on the subject. One of the important things is to have a lot of moisture in the dirt when you are working with it. and let the track/jumps dry, then wet them, let them dry/bake and repeat a few times. I think that is the hardest part not riding the track when you are done, but in doing this the jumps/track will last much longer w/ less prep because the jumps/track will be much "harder/baked"

good luck and post some pics when u get done. Looks like i am gonna have to wait another year to build mine :-(, but hey at least i own the land and can ride everyday

http://www.skidlidvideo.com/TrackBuilding/Medsker%20Racing%20College.htm

"Fifth gear wide open, can't go wrong"

Not sure what you have to work with (old track/dirt) or what you are trying to achieve but get a good D4 (my preference) and start pushing dirt. Take your time and get a feel for it with the corners and whoops first, then work your way into jumps. You will get a feel of the right angle/length and height you need for the jump face. Until you get some ass time on the dozer dont rush... you will just have to fix it later.

Trail and error....

Just like a good dozer operator didn't read how to "drive it" in a book, the only true way to learn is to do it.

I was in the same boat. im only 19 and had a track built when i was 15 by a guy who has built tracks before. well the track became way to easy and beat up so last year I rounded up some equipment (skidsteer with tracks, front end loader, and a 450c dozer) and built it myself. I would consider myself very skilled at running things like this do to my understanding of how the machines worked (being around equipment my whole life) and had zero experience besides a little bobcat before I did this. It turned out amazing and I would deffinantly build up a game plan before you start. walk the property and find the natural drainage paths and utilize them. find areas where you can get dirt from without creating a pond or water back up and where you can actually move the dirt to (you cant push dirt forever stay close to your targets) as for jump building you will realize a ten foot tall pile (at peak) of dirt will turn into around a 5-6ft tall jump if not smaller so you may need to keep adding. If you would like more help just ask me I have some pics of my track on my profile here ill see if i can figure out on how to upload them into the thread. as for angles that comes with knowledge of riding, almost every jump on my track is between 60-80ft and about 8-10ft tall i got the angles right first try just by trusting my instinct, its kind of trial and error and who has the balls to try and launch it first.

labtop is away for fixing ill have it this weekend i dont know if i can find the rest online ill check as of now this is the only one i can find

never built jumps for a big bike,

but i built a pretty sick 6-pack for my 110 last year... use a lot of water. that was my one downfall, but i didn't have any access to water

found these one is before the other in time periods the one with the bigger jumps is how it is now but i have added some whoops and a few doubles inbetween the bigger jumps

before i forget avoid a bobcat with tires if you can more of a pain in the ass for finalizing jumps ive had both out there and tracks make your life (what ever more it costs) easier. luckily i have good connectons with equipment though

i like to start with piles that are 1.5-2 dozer blades wide and about the hight i want the finished jump to be. then i pull the blade all the way up and drive right up and over using the tracks to pack the whole jump down. this also helps get the basic shape because the blade will knock off the top of the pile it is way to steap. then you pile up more dirt and repeat untill its back up to the hight you want and fully packed down. Then back blade the face of the jump to get the desired profile. i can't really give you an exact angle or anything but you will get the feel for it.

Definitely get something with tracks. Building a good lip is all about the feeling. You should know from riding how it should look and once you build one or two and ride them you'll know what if anything you want to change.

you got that right most operators can't even read lol
i would know i'm one of them!