Fabricating FMX jump

[rm_racer]

Hey,
I didnt know where to put this, so I figured this would be a pretty good place.

Anyway, Ive been planning a 4-6 foot kicker jump made out of steel, then screw on a rubber mat type thing for some grip on the face. I have a cuple questions first thought. What would be a good angle so theres lots of height, but I dont want a huge long gap, becasue I have space issues (need to clear the area and fill it, so smaller the better)? Im thinking maybe a 20-30 foot gap, with 10-15 feet of height, and to be able to clear it in about 3 gear tapped.

Now some things about the fabrication. (hoping to be a fabricator or machinist when I graduate collage, but I have a while to go). Im thinking 1 inch square tubing. I dont have a welder, and that will be the most expensive to get. I have welded slightly thought. Ive drawen up some plans to, I can post them if I find them if you want.

1) Im thinking a mig with gas, not Flux core?
2) Whats a good brand of welder? Ive looked at miller and Lincoln. I found a Lincoln on **** for 280$us that runs on 115 volt standard power. Ive heard that the 115 volts are not very dependaple, is that true? Its a 20% duty cycle at I think 80amps, I know that is slightly low, but I dont have a huge budgit here.
3) Almost done, I really dont want to go buy a tubing bender, so how can I bend the tubing for attaching the sheet metal for the face?
4) Finally for now, how thick is 1" square tubing typically?

Thanks for reading the long post. Im asking here becasue im sure some of you have done some welding, and can help me out with the angles and stuff.

Thanks again!
Ryan.

 

[dklink2000]

I have a Lincoln mig that runs on 115. It works fine for light work, but I wish I went bigger. That being said I have no dougt that it could do what you are talking about.

 

[YZ165]

Try this.....

www.fmxschool.com/

Thee's a few good pics and some info there that will get you started.

Then look around here. http://www.fmxramps.com/plans.html They give the correct numbers for building a ramp. If you don't want an 8 foot ramp, just reduce the numbers by 20% or so and go from there.

And this has the answers to most of your other questions. http://www.fmxramps.com/rev1.html

That last one is important. Get the numbers right. The first ramp I built was not to thier exact numbers and it sux. The second one I built was a Rev.1 and we still love that ramp.

Oh, one more thing........I wouldn't reccomend hitting one of these in 3rd tapped for a while.....that would be considerably farther than 15 feet in the air and 30 feet in distance. Start small and work your way up, Good luck, YZ165

 

[ellandoh]

this is 3rd gear tapped :cool:

 

[YZ165]

So is this! :aj:

 

[ellandoh]

got some distance their yz165 wish i could see the rest of that ramp

 

[YZ165]

Here's a couple of the ramp.

 

[YZ165]

And here's a few more.

 

[rpmRMiam]

They have cheap arc welders al Wal-mart th :cool: at would be great for 1" tubing and even a little bigger. And if it sucks, take it back when you are done! :cool:

 

[ellandoh]

i need to move to new mexico those pics look like the riding area goes on forever :nod:

 

[rm_racer]

Ok thanks. Maybe ill keep it in 2nd, lol. Thanks for the pics and the links, they gave me some ideas.

I have another question now. They say to use 3/4" #9 expanded sheet metal, but was thinking of using a big sheet of rubber screwed to the ramp, becasue I can get some for free. What do you think?

 

[Dirt Bike Dan]

I have another question now. They say to use 3/4" #9 expanded sheet metal, but was thinking of using a big sheet of rubber screwed to the ramp, becasue I can get some for free. What do you think?

From a physics stand point, that sounds very dangerous. The forces from the bike will put tremendous strain on the rubber, eventually(if not the first time), the bike will go through it.... :ohmy:
Spend a little more, and the result will be a much safer, stronger, longer lasting ramp.

I've never built a metal ramp, but you might be able to use wood for the face. Either way, you're probably going to want to put something on the face for traction, either that rubber, or a textured paint (for a garage floor).

 

[rm_racer]

Lol, I was going to put sheet metal down first, then rubber for grip. Thanks though. On the web site it says I have to put sheet metal down even if I use wood.

 

[YZ165]

Rubber would work great, but it has one small downfall. If it rains, you're through untill you get it dry. The wood on my ramp is pretty slick when wet as well, but soaks it up pretty quick. The expanded metal would be the best for sure, but at $50 a sheet, and you need 3 sheets, it deffinatly increases the bottom line. As long as you have the middle bar on the face for support, wood is fine. 3/4 inch ply has lasted me two years and still going. YZ165

 

[YZ165]

i need to move to new mexico those pics look like the riding area goes on forever :nod:

Not quite forever, but far enough to run out of gas for sure. Come on down, I'll show you around! ;) YZ165

 

[High Lord Gomer]

I have never done it, but have read from freestylers that the traction on expanded metal ramps is better than dirt.

I like YZ165's carpetted approaches to the ramps!

 

[YZ165]

I like YZ165's carpetted approaches to the ramps!

Old conveyer belts from UPS. Where we use the jumps is mostly sand, so huge ruts develope right in front of the ramp. The belts keep the ruts from forming, and it's great traction for the approach!
Oh, and as far as traction on the ramp. it is better than on dirt! :aj: