Introduction: Scrappy Multifunction Bike Ramp & Teeter Totter
- It seems being stuck at home has resulted in a lot of bike ramp/kicker designs being posted here lately. I'm going to add my own 2 cents with a multipurpose ramp / teeter totter for bikes made with 100% scraps and hardware I already had on hand. Zero hardware store trips for this project; I don't know about you but I'm impressed!
This design is a one-off in its details because of my constraint of using materials on hand. But I hope that you'll be inspired to do something similar for yourself. We're already having a lot of fun with it, and have just started learning the skills we need to use it to its fullest.
I've wanted a bike teeter totter since I first rode one about a year ago at a NICA "try it" event. (If you've got kids, check them out!) That one was a 2x6 on a black iron pipe hinge mounted in a short "A" frame.
Why a bike teeter totter/ramp?
- First, because it's a fun toy to get us on our bikes more!
- A narrow riding surface helps riders learn body control and balance (neutral and ready positions).
- Cresting a ramp at low speeds requires awareness of pedal position (level!) to avoid striking.
- Coming down the far side gives practice "pumping" to gain speed without pedaling.
- Riders learn wheel lifts and control in the air as they increase speed over ramps.
- A teeter totter teaches control and balance even beyond a simple skinny ramp. Speed control is also more critical.
- A teeter totter is terrifying at first, but such a confidence booster once you master it.
- Did I mention it's fun?!
- ... which means the kids will build one anyway with rotted wood over rocks, with rusty nails for spice. Le'ts put some thought into this so it's less likely to maim and more likely to work well.
The idea for this ramp build started with an 8' x 9 1/2" strip of 3/4" plywood that was left over from a bookcase project and morphed into reality this week! Throughout this 'ible, I'll share my design/build/revise process, but it started something like this:
Problem 1: That plywood isn't strong enough on its own to support weight of a bike & rider.
Solution 1: Frame it underneath somehow...
Problem 2: The typical A-frame/hinge design for a bike teeter totter leaves exposed pointy edges that look painful. I want something that accounts for the fact that my kids (including my 6-year-old) will fall off of and bang themselves / their bikes on it.
Solution 2: Make it pivot on the ground, as one solid piece.
Opportunity is knocking: Well, an inverted wedge would make a great teeter-totter. But upside down, it's a ramp! No, make that 2 ramps! This is getting better...
Problem 3: A balanced ramp will teeter but not totter back (reset itself) for another ride.
Solution 3: Make one ramp a curved kicker ramp that has less material so it will always be lifted back in the air. Plus, now it's got two different ramps to ride!
Nice. Let's hit the scrap pile.
- 8' length of 3/4" plywood (mine was 9 1/2" wide, which worked really well)
- 4 pieces of 2x12 lumber (~34" lengths from replacing basement stair treads)
- a bunch of 2x6 and 2x4 cut-offs at least as long as the plywood is wide
- leftover section of flexible 5mm "luan" plywood
My Fasteners (I had all these on hand, and you'll likely have similar ones)"
- Wood glue (if I hadn't used up all my Power Grab on the stairs project, I would have used some here)
- LOTS of screws, mostly 2 1/2" long but as short as 3/4" will be useful. Deck screws, drywall screws, wood screws, and some pocket hole screws.
- tape measure
- carpenter's ruler
- speed square
- carpenter's square
- chalk line
- hand saw (Japanese style pull saw)
- miter box
- circular saw
- straight cut jig for circular saw
- drill w/ bits
- clamps of various sizes
- small box plane
- router (makes rounding corners easy)
- dremel with grinding bit
Step 1: Start With a Plan
After scratching some ideas out on a piece of scrap paper (scraps all the way down!) and some searching of existing bike teeter totter and ramp/kicker designs, I settled on the one pictured above.
I'd join two 2x12's end to end and cut them into the wedge profile to create the ramp/teeter totter fulcrum shape, make a mirror image of that, and attach both to the long edges of the plywood. Then I'd attach 2x4's across to make it a ridable deck surface, with most of them as wide as the plywood but the ones at the top extending farther to stabilize the teeter totter.
The hardest part was figuring out how to get an appropriate curve for the kicker side. Most instructions suggest curving a piece of PVC pipe until the curve is "just right" and tracing it. I don't have the experience to identify "just right" vs. too shallow or steep for the beginners (including myself) in my house, but some searching suggested about a 30 degree takeoff angle was a good place to start. With some more searching and using a circle calculator online, I decided on a ~7 1/2 foot radius arc for the kicker ramp.
Step 2: Shaping the "frame"
First, I clamped two of the 2x12 pieces to the plywood with a 2x2 over them to simulate the top of the ramp deck. I used a chalk line to determine where the top surface of the ramp needed to run. I then used the carpenter's square to draw a line 1 1/2" (the thickness of the 2x4 deck) below that for my initial cut. The straight cutting jig helped make that nice and even. Then I traced this line onto the other 3 sections of 2x12 and cut them.
A piece of bailing twine looped over a screw, tied to a pencil and adjusted to 7.5 feet served as my compass. I used the carpenter's square to extend the line of the board out to where the plywood will end, aligned both ends of the arc, clamped the board in place, and traced the curve. (Repeat on the other side.)
Since I don't have a jigsaw, I did some searching on ways to cut this curve well. I went with cutting 1/2" depth at a time, freehand along the traced line. It came out very well! My advice: DON'T SKIP THE EYE PROTECTION during this even if you normally do. I was very glad that I wear glasses since sighting along the curve required putting my face in the path of flying wood chips.
Now I've got two straight slopes and two curved "kicker" slopes ready to hold everything where it belongs...
Step 3: Connect and Square Frame
Before connecting the 2x12 sections to the plywood, I drilled a few pocket holes on the backs of the straight ramp segments to help join them to the curved segments. Then line up with the center, glue and screw the 2x12's to the plywood and to each other. (This thing is starting to get heavy...)
To finish out the framing portion, I wanted to connect the peak/fulcrum together. The top decking sections I cut to about 18" long so that in the teeter totter position it will have some more stability. Also, these are going to see more forces (especially during jumps) and contact with the ground so I used the scrap pressure treated 2x6 for these.
I angled the circular saw to 15 degrees and ripped one edge of the top decking board for the straight slope, then glued & screwed it in place. The clamp you see in the picture was squeezing the ramp sides together because they were spreading apart to almost 10.5" at the peak. The top decking section for the kicker side got a 30 degree segment ripped, and the faces of the planks met really well! The steeper slope meant the top edges didn't meet so nicely. Should've seen that one coming (geometry and all), but the box plane brought them into line no problem.
Now the four sides of the ramp frame are square, glued & screwed. Time to finish the ramp decks!
Step 4: Finish Ramp Surfaces
Time to trim some 12-15 inch scraps into 9 1/2" deck boards and get them on the ramps. I measured both for 9 1/2 inches and for the speed square edge (5" away) to guide the saw. These are really small pieces, so clamping was needed but they went pretty quickly.
Another 2x4 scrap served as 1 1/2" gap gauge for the planks, and each got glued and screwed down to the ramp frames.
Now I've got a 1 1/2" ledge to hit at either end, which is a bit much. How to transition the bike wheel up to the 2x4's? My first thought was to rip some more full-width 2x4's at angles to turn them into ramps. But I have no table saw, and a test rip with the circular saw at its maximum 55 degree angle showed that approach wasn't going to work.
BUT I have the cut-off wedges from the 15 degree angles of the ramp frames! (Yes, the scraps cut off of the scraps.) I cut 10 door-stop looking wedges off of those larger wedges, then glued and screwed them down to the plywood base. (NOTE: These are small, and drywall screws are wedges. Pre-drill the holes like I did... after the first one.) Some careful selection of screw lengths and positions successfully kept any screw points from sticking out on the other side. Bonus!
A test on the work table showed that the teeter totter action is reliable and not too fast. That's a relief. I'd thought I might have to add weight to one side or the other if it didn't work well at this point, but the thing is already pretty heavy so that was nice to avoid. (I want my kids to be able to move this around independently.)
Lastly, before riding the ramp, I smoothed all the corners with my router and roundover bit. I fully expect people riding this to crash multiple times as we experiment, so I'd like to make it minimally damaging to our bodies and bikes. I was very pleased with how everything came out, so it was time to carry it around to the front yard and give it a go.
I am able to carry this by myself (but it's not super fun) and my older kids (12 & 10) can team carry it safely.
Step 5: Ride It! Break It! Fix It!
This thing is pretty fun, and we have a lot of growing room with it. It's narrow enough to keep you on your toes but wide enough that beginners can have success. The two ramp faces feel pretty similar at low speeds, but as you go faster you can definitely feel that kicker starting to do its thing. One day we'll get some nice air off of it!
The teeter totter is a ton of fun! It will have all different challenges at higher/lower speeds, but the easiest speed is the slowest one where you can coast up and over without pedaling. This is a bit faster than the ramp coasting speed and takes some experimentation. One day I'll do a track stand on the balanced teeter totter, I swear...
But one problem: When the kids decided to run up and over the teeter totter (cuz it's fun), one of them landed with a foot planted right at the end of the 2x12 frame as it hit the ground and the plywood started to break. I should have seen that stress concentration being a problem, as I realized when I heard the "crack." (This is only an issue on the kicker ramp side, since the flat ramp lays flat along the ground and spreads the load nicely.)
So, BACK TO THE SCRAP PILE! This time, some 5mm plywood (luan) was waiting for me. It would bridge the gap and re-surface some of the kicker ramp. A quick trim to 9 1/2" wide, and out to the yard for a field repair. After making extra sure the decking screws were flush or below the 2x4's, I glued it up and secured the bottom with some 1" self-drilling pocket hole screws. Then I pressed the plywood down to pre-drill and countersink for the 2 1/2" wood screws and secured everything down.
If you're playing along at home, you might have noticed that 5mm (~1/8") luan plus 3/4" plywood is less than the 1" screw lenth. So about 1/8" of those pocket hole screws were waiting to destroy a finger, clothes or bike tire. Nothing that grinding with a Dremel can't fix. And some lovely fireworks to boot!
Will this be the end? It's holding up well, but will doubtless need more repairs/tweaks as we go along. I hope this was helpful for you!
Participated in the
Scraps Speed Challenge