MadPikAvenger's Super-Magical Funland: July 2009

Jumping the Bike

As promised, a video of us jumping the bike into the lake. Enjoy.

What you need:

Here's what you do:

First, figure out the your desired radius for your ramp. Typically between 8' and 12' works well. We built one of each. The taller ramp is the 8' radius while the shorter one is the 12'.

Once you've figured out your radius cut a piece of string to that length. Stretch the string out along the short side of your sheet of plywood so that the end of the string is in one corner of the plywood and the other end is straight out. Have a buddy hold the other end tight while you use a pencil to trace your curve on the plywood. Sorry I don't have any pics of this. You don't need to trace both sides of the ramp at this point since you'll be using the first side as a template to cut the second.
Once your line is traced cut it out using a jig saw.
Now that you have one side cut out use it as a template to trace onto the remaining 3/4" plywood. It should look something like this.

Now that the shape is cut its time to cut the 2x4's. Since we only built our ramp for launching off of and landing on we decided to make it 2 feet wide but you could easily make it 4 feet wide instead. However you may need some more 2x4's.
Depending on whether you decide to build a 2 foot or 4 foot wide ramp you'll need to cut the 2x4's to the appropriate width.
Once that is done line them up evenly along the curve of the ramp as they'll act as the supports.
Once you have them placed where you're going to want them, trace their outline on the plywood as you can see here.

Once that's done cut those sections out with the jigsaw. You should end up with something like this. Again use your first side as a template for the second.

Now cut the extra 2x4's into 4" sections. You'll need 2 for each cross beam on your ramp. We used 4 cross beams so we needed 8 4" sections.
Your going to want to screw these to your cross beams on either end. Make sure you measure and place them 3/4" from the edge of the cross beam.

Now simply shoot some screws into the 4" 2x4 pieces you screwed onto the cross beams like this.

Next its time to screw on the top of the ramp. This will be easiest if you soak your 3/8" sheet of plywood in water for a while, or let the hose run over it while you build the ramp. Either way, line the 3/8" plywood up on your ramp and screw it down into the cross beams.
The rest is just finish work and adding supports where you feel them necessary. We added a horizontal 2x4 at the bottom of the ramp and another in the middle of the back of the ramp.

Tada! Ramps!

I'll post some videos of the ramp in action as soon as I get around to getting them on my computer so stay tuned!

Just a little video I threw together quickly of our first trip to Silver Lake this year.