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Challenge: Create a steel bicycle with customizable geometry light and rugged enough for off-road racing.

 

Rattlesnake Cycles is something of a pet project of Acuity Design that stemmed from a former colleague and friend of the founders asking if they could build a custom, lightweight, steel bicycle for him. The project was more challenging than we originally thought, but so much fun we’ve done it a few times since! Steel bicycles offer a wonderful riding experience, but making an extremely lightweight steel bike can pose several issues. Precision fixturing and low-amperage TIG welding are necessary skills when working with very thin-walled steel tubing. Making sure the welded bike geometry turns out as designed also takes quite a bit of work and planning.

The first in the design process, as is the case with anything we do, is finding out exactly what the customer wants. In the case of custom bikes, that involves taking into account the type of riding the rider will do, the terrain that will be ridden over, and the physical dimensions of the rider’s body. A skeleton of the frame geometry is then made which a 3D CAD model of the bike can be generated from. This allows us to check tire, crank, and rider clearances. The other perk with using CAD in this case is creating drawings of the tubes to make sure that the tube miters are precise. Welding such thin-wall tube without perfect miters is nearly impossible.

Now, the fabrication begins. The tubes are mitered and then loosely assembled on a bicycle frame jig that has the geometry set to the intended dimensions of the frame. Setting the jig is a very time-consuming and detail-oriented process. After the jig is set and the tubes are placed, the frame can be tack welded together. With tack welding complete, the frame is removed for finish welding and cable routing features. Paint or powder coat is next followed by decals and clear coat. The last step before assembly is precisely reaming all the bearing surfaces on the frame. The bike can then be assembled and is ready for the trails and roads. Each bike can take up to a hundred hours with all the design, fixturing, and fabrication, but all that time is well worth the ride!

Contact usto learn more about custom bicycles from Rattlesnake Cycles.