Stinger
 

*** Featured in MAKE Magazine, Makezine.com, and Instructables.com  ***
A girls' bike becomes a kids' custom chopper with extended forks and low rider seat.

Here is a simple chop that only involves cutting and relocating the seat tube on a kid's bike frame in order to create an ultra low progressive style chopper. The original frame can be just about any frame you have laying around, and the only other part you will need is a set of forks from a 26-inch mountain bike, or 27-inch road bike. Because the resulting chopper has steering characteristics similar to the original bike, this make a great "training chop" for the new rider.

Here we start with the pinkest, "sissiest" looking bike I could drag from the ever growing scrap pile in the corner of my garage. The cheap steel frame cycle has 14-inch wheels with a coaster hub, and is as basic a bike as can be found (Photo 1). I actually didn't mind the blue-green rims and white trimmings, but that pink has to go!

Photo 1 - Ugh! Can a bike be any more "girlie" looking?

The entire bicycle was stripped down in five minutes, and all of the components appeared to be in good shape and functional (Photo 2). A couple of spokes needed to be tightened, but that's no surprise. The next time you are at a department store, have a look at how loose most of the components on the kids' bikes are.

Photo 2 - Bicycle autopsy completed.

The plan here is to cut the original seat tube from the frame, and re-weld it in a new position, placing the seat lower and farther back on the bike. This attitude adjustment will give the bike a chopper look without radically changing the overall feel and steering characteristics of the original cycle. Cut the seat tube using whatever method you like, but try to keep as much of the tubing as possible, getting as close to the bottom bracket as possible. Take about two inches of the seat stays off with the seat tube as well (Photo 3); this will allow the tube to be placed further back.

Photo 3 - Cut out the seat tube.

Once the seat tube is cut from the frame, grind the leftover metal from the bottom bracket and remove the two small seat stay stubs from the seat tube. The seat tube should then be ground to make a good joint with the down tube and placed in a position similar to the one shown in Photo 4. The end of the top tube will also need some grinding in order to form a proper joint with the seat tube.

Photo 4 - Setting up the frame for welding.

Once the frame is cleaned up, and all tube ends are ground for proper fit, weld the seat tube into its new position (Photo 5). There should be no problem with alignment, since the original tubing is all still properly aligned - just make sure the seat tube clamp is placed so the bolt is facing the rear of the bike.

Photo 5 - Seat tube welded in place.

A set of chrome road bike forks from one of those 1970's department store 10 speeds was added to the bike to give it a bit of lift (Photo 6). Because the forks are only longer, and the head tube angle has been unmodified, the bike should handle pretty much the same as it did before.

Photo 6 - Longer forks added to the bike.

Before painting, the bike is slapped together in order to make sure everything fits together properly (Photo 7). The handlebars are cut to mere stubs, and the seat is placed just above the rear wheel. The drive train will go back together without any trouble, as nothing has been modified here.

Photo 7 - Components added.

The painted bike is shown in Photo 8. The horrific pink was replaced by a greenish blue that somewhat matches the original rim color, and the white accents were kept. A fat square rear tire was found to replace the skinny original tire (it was from a dead wheelchair).

Photo 8 - The Stinger, painted and ready.

Tanner poses it up with the Stinger, just before the first test ride (Photo 9). With the seat so far back, and the handle bars up so high, this chopper sits much like a recumbent bicycle.

Photo 9 - Thumbs up for this chopper.

With one quick push, Dad launches Tanner and the Stinger into the great wide open (Photo 10). Riding this chopper was no more difficult than any kids' bike. Sure, there were a few shakes, but we all have those for a few blocks - admit it!

Photo 10 - Ready for launch.