ATTACK™ Swingarm Series:
What do you get when you combine decades of sportbike drag racing development with the unique traction challenges of a Harley-Davidson bagger? Introducing the ATTACK™ Swingarm series by Brock’s Performance. Our ATTACK™ Swingarms use an offset pivot design to create a higher effective pivot point, increasing swingarm attack angle and anti-squat so the rear tire is driven into the surface under power instead of being unloaded as the bike squats.
That added geometry advantage is especially valuable on a Harley-Davidson chassis because the swingarm pivot passes through the transmission/primary structure, leaving no practical way to raise the pivot the way engineers can on a modern sportbike. The ATTACK™ Swingarm builds that benefit directly into the swingarm itself, delivering improved bite, better chassis attitude under acceleration, and more usable traction for stock engine, big-inch, turbo, and nitrous applications alike.
Short ATTACK™ Swingarm:
Built for riders who want improved drive without committing to a full long-bike setup, the Short ATTACK™ covers stock to +4 inch applications, with a pivot centerline to axle-slot centerline range of 17.5 inches (444.5 mm) to 21.5 inches (546.0 mm).
The Short ATTACK™ is ideal for riders who want stronger acceleration while keeping a responsive chassis for stock/short wheelbase drag racing, roll-ons, twisties, and land-speed use.
Please note: The Short ATTACK™ Swingarm is a direct OEM replacement part designed to replace the OEM swingarm with no additional modifications. In some applications, the full 4" (101.6mm) over length cannot be reached due to interference with the rear fender or tail light assembly. Always check for safe dynamic operating clearance when making chassis modifications.
Not sure which ATTACK™ Swingarm is right for your build? View the ATTACK™ Swingarm Comparison Chart.
- 6061-T6 Aluminum swingarm handcrafted from proprietary extrusion
- Bolt-on design can be used with OEM rear wheel, caliper, spacers, and associated components *Extended belt or chain conversion and brake line are required for full range of adjustability*
- Adjustable extended wheelbase: Stock to +4" over applications
- Designed for use in high-power, high-torque applications
- Includes centerless ground hollow 4130 chromoly axle
- Reversible billet aluminum axle adjusters for easy wheel adjustments
- Integrated threaded mounts for optional swingarm spool installation
- Includes newly-revised caliper bracket for use with most aftermarket brake caliper setups *See ‘Technical’ tab for details
- PTFE®-lined spherical bearings from Worldwide Bearings are preinstalled
- Includes spacers to use the OEM 3/4” pivot shaft
- Interior swingarm width measures 10 7/8” at the axle (accepts 200 series rear tire on 6.75” wide rim with chain conversion)
- 36% weight savings vs OEM swingarm (see the 'technical' tab for details)
- Designed, machined, and assembled in the USA
- Burnished raw aluminum finish
- Click here to view installation information
- Click here to view the pivot bolt stack-up engineered drawing
- Overall hub width is critical for proper operation/handling. See the 'Technical' tab for important information regarding installation
Shock/Rear Brake Information:
- 3-position shock mounts allow flexibility in ride height (stock, -1", -2")
- Brock’s Performance recommends adjustable Bitubo shocks for the best performance and adjustability
Attack Bagger Swingarm Weight:
- Swingarm w/Bearings: 12.50 lb. (5.67 kg)
- Axle w/Nuts:
- 25mm - 2.48 lb. (1.12 kg)
- 28mm - 2.77 lb. (1.26 kg)
- Axle Blocks:
- 25mm - 0.76 lb. (0.35 kg)
- 28mm - 0.74 lb. (0.34 kg)
- Pivot Bushings: 0.43 lb. (0.20 kg)
- Brake Mount w/Screws: 0.55 lb. (0.25 kg)
25mm Total = 16.72 lb. (7.58 kg)
28mm Total = 16.99 lb. (7.71 kg)
OEM Harley-Davidson® Swingarm Weight: 22.78 lb. (10.33 kg)
OEM Harley-Davidson® Axle Weight: 3.55 lb. (1.61 kg)
Total = 26.33 lb. (11.94 kg)
Total Weight Savings = 9.61 lb. (4.36 kg) or 36% of OEM weight
Attention: When spacing the Bagger rear wheel, the overall width, including spacers, brake hanger, etc. Must be: 10.875 in +.020in/-.000in / (276.22mm +.50mm/-.00mm)
Overall hub width is critical for proper operation/handling, product longevity, and rider safety. Brock’s Performance will not warrant any damaged swingarm found not to comply with these spacing guidelines.
*Attention* If using an aftermarket brake hanger, care must be taken to ensure it does not bottom out on the supplied caliper mounting bracket. Failure to do so can lead to swingarm failure, loss of control, injury, and even death.
Exhaust Clearance Note: Due to the offset pivot point and changes in suspension geometry, the swingarm sits at a greater downward angle (axle is lower than pivot shaft). Depending on the exhaust system used, additional clearance around the muffler may be required to clear the axle.
American V-Twin Fitment Statement:
Although all attempts have been made to handcraft a product that will fit a wide variety of machines for a particular make/model/year, due to idiosyncrasies between particular years, available options, accessories, etc., fitment cannot be 100% guaranteed. If, upon assembly, fitment issues are discovered that are beyond the installer's ability or willingness to correct, then please feel free to contact our customer service department, alert Brock’s Performance to the fitment issue for your particular make/model, and obtain an RMA (Return Material Authorization). Brock’s Performance will accept unmodified swingarms in 100% resalable condition for a full refund.
Please note that refunds are issued after product inspection at Brock’s Performance, and the customer is responsible for any/all shipping charges.
