Roaring Toyz offers a sleek...
Roaring Toyz offers a sleek yet strong design.
Whether it's a racer at the drag strip or a blinger at the strip club, custom swingarms are the foundation for a hot ride. Wide tires wouldn't exist if there weren't modified arms to hold 'em, and seven-second quarter-mile killers couldn't get down the track without a competent stretch either.
There's more to an aftermarket swingarm than just welding a few extra inches of aluminum to the stock unit however, and without precise calculations and a little science sprinkled in you'll be ruining bearings, breaking chains and spinning sprockets faster than the Kardashians go through marriages.
Some swingarms have to cope...
Some swingarms have to cope with over 600 HP pounding through them.
While there are numerous swingarm manufacturers, not all are created equal. In fact, we've seen many firms come and go over the years due to questionable material or construction techniques. These aren't parts that you want to take any chances with, you know.
At the forefront of swingarm design and fabrication are Roaring Toyz and Myrtle West, and SSB checked in with them for a closer look at how two companies take different approaches to building a similar product.
How do you build a swingarm for a new bike?
Robert Fisher, Owner, Roaring Toyz:
When a new bike comes out the first thing we do is pull the stock swingarm and rear wheel off. We measure the wheel and sprocket offset. CNC machining is common in...
CNC machining is common in aluminum work, and roaring toyz uses several machines to help precisely cut its swingarm components.
John Rehm, designer and engineer, Myrtle West:
The first thing is to find out if any major changes have been made to the new model. We do all we can to check compatibility with the older models and try to borrow a bike from our local dealership. After we get the bike we remove the swingarm and wheel, then we do a layout of our arm and wheel to make sure it will fit just like the stock arm. How are thickness, bracing and length determined?
Fisher:
We have special extruded tubing with an inner rib for strength. This tubing allows us to be super strong and super light. We also have a new system for underbracing that we call "Stealth Underbracing" that really keeps the swingarm stiff. We used this technology on the "No Joke" AMA Pro Street Dragbike that recently set a new record of 209 MPH in the quarter-mile-making it the fastest street bike in the world. Length is determined by customer request, but we 'overbuild' all of our swingarms so strength will never be an issue.
A proper swingarm requires...
A proper swingarm requires more than welding some bent steel tubing together. Roaring toyz uses a unique fitment structure.
Myrtle west has its swingarm...
Myrtle west has its swingarm stock built to exact specs. the inner rib helps assure strength and safety.
A jig guarantees consistency...
A jig guarantees consistency in all of the welds on a myrtle west swingarm.
Rehm:
Our swingarms are made from custom tubing of our own design. All of our 300mm tire and up sized arms come underbraced, while our 240mm tire size and stock dimension arms don't require under bracing until they are extended over 10 inches.
When we do apply the bracing we take into consideration the placement of specific exhaust and suspension components to make sure there is no interference with them.