Building a Launch Ramp/Jump

This idea started one day when my buddy and I were out mountain biking on a super hot summer day. While taking a break we rode out bikes out onto a dock along the river and we both stated at the same time how much fun it would be to jump our bikes into the lake. So we raced home, bought $30 worth of lumber and a $10 garage sale bike, and got to work.

So here's what you'll need:

• 1 8'x4' sheet of 3/4" plywood
• 1 8'x4' sheet of 3/8" plywood
• 2 8' 2x4s
• A bunch of deck screws (Make sure at least 16 are 3" long)

Now here's what you do:

• First, figure out your desired radius for your ramp. Typically, a radius between 8' to 12' works best. We built one of each, the taller ramp is the 8' radius, while the shorter one is the 12'.

• Once you've decided on a radius, cut a piece of string to that length. Place the end of the piece of string in one corner of the 3/4" sheet of plywood and stretch the string out along the 4' end of the board.
• Have a buddy hold the other end of the string tight and using a pencil trace your curve across the plywood.
• Cut along the line and you now have one side of your ramp. Trace the curve onto the remaining 3/4" plywood and cut along the line again. Leaving you with something like this.

Now that the sides are done it's time to cut those 2x4s.

• Since we were only building our ramp to launch off of we decided to make it 2 feet wide. If you want a wider ramp you may need more 2x4s.
• Anyway whatever width you decide for your ramp, that's the length you want to cut your 2x4s.
• Since our ramp is going to be 2 feet wide we cut the 2x4s into 2' sections.
• Once cut place them along the edge of the curve spaced equally apart and trace their outline like so:

• Once that's done cut along the lines. You should end up with something like this:

• Again, use this as a template for the second side.
  
• Now cut the extra 2x4s into 4" sections. You'll need two 4" pieces for each 2' 2x4. We used four 2' 2x4s so we needed eight 4" sections.
• You are going to want to screw these to each end of the 2' 2x4. Make sure you screw them 3/4" in from the end.

• Once those are complete simply slide them into the sides your made earlier like so:

• Now simply shoot some screws through the sides into the 4" pieces like so:

• Now its time to screw the 3/8" plywood down for the surface of the ramp.
• Since our ramp is only 2' wide we obviously cut the 4'x8' sheet in half lengthwise
• The sheet of plywood will bend easier if it has been soaked in water. We simply let water from the hose run over it while we were building the rest of the ramp.
• Just lay the plywood over the top of your ramp an slowly bend it into place and screw it down into the 2x4 cross beams.
• Tada! You now have a ramp.

So how did they work you ask? Here's a video we shot of the ramps in use. I'll let you be the judge.