A balance bike is a small pedal-less bike used for teaching toddlers how to ride, and they offer many advantages over using training wheels. If you'd like to read more about balance bikes, twowheelingtots.com is a great site with loads of information.
There are many commercial balance bikes available, but they can cost quite a bit. I made this balance bike from a used child's bike in a few hours, and it only cost me $5.
There's slightly more to it than just removing the pedals, crank, and chain from an old bike and just plunking your kid onto it . . . but not much.
Take a look at how I tackled this project, and let me know what you think. Hopefully there's enough information here to help you make your own. Thanks for looking!
Step 1: Find the Right Candidate
To achieve this as easily as possible, I recommend looking for a bike with 12" tires, and a frame that is designed with one main tube that goes from the head tube to the seat post/bottom bracket area. A lot of kids' bikes have frames shaped like this, so it shouldn't be too hard to find. Bikes with this kind of frame should be pretty easy to modify to get the seat just a little bit lower than what is possible as they come from the store. (I would specifically avoid traditional-looking frames if you can, as they will require a lot more work--welding and such--which is beyond the scope of what I was willing to do for this project.)
I found this one at a thrift store, and it happened to already have two decent tires and inner tubes that didn't need patching. Nice find!
After some very slight modifying of the seat tube, the seat is low enough for my 2-year-old. The nice things is that the seat is still adjustable so I could raise it up if we needed to in the future.
Step 2: Disassemble the Bike
Use a chain tool to remove the chain. (My frame was such that it just slid right off.)
Note the setup I used to help loosen the pedal on the far side. The block under the near pedal allows the wrench on the far side to be driven toward the ground, loosening the pedal. To remove the crank, you only need to remove the pedal on the non-chainring side. Once this pedal is off, remove the opposite-threaded nuts and washers on the non-chainring side, and pull the crank out.
Step 3: Lower the Seat Post Clamp
I did this with my dremel tool and a metal cutting disc.
I began by cutting directly through the small weld holding the seat post clamp to the seat tube, and pulling it off of the tube. I ground down the remaining weld so that the clamp could be freely slid back onto the tube and down as far as it would go.
With the clamp removed, I drilled a hole further down on the back side of the seat tube, below the existing slot that allows the seat tube to be pinched tight around the seat post. I then used the metal cutting disc to extend the slot down to the new hole.
The seat post clamp was slid back into place at the bottom of the seat tube, and the remaining upper portion of the seat tube was cut off.
Step 4: Remove Excess Stuff From Frame
Step 5: Clean Up and Paint
Step 6: Re-grease Bearings
This was a new experience for me, but it turned out to be very easy. There's a ton of information online about how to do this--I just watched a couple of youtube videos on the subject and I was ready to go. I did have to go out and buy a set of cone wrenches, but these will surely come in handy down the road.
Step 7: Polish Up the Chrome
The left side of the handle bars had looked just like the right, but after a few minutes with some foil they started to shine right up.
Step 8: Reassemble the Bike
It's not exactly the same as the kind you can get from the store, but it's perfect for what we needed. The funny thing about these bikes is that kids will only ride them for a little while before they're ready for a regular bike. So I intend for this to be a heavily used loaner so all my friends' kids can learn on it as well.
Thanks again for looking!