15 Bolt

When strength, ground clearance and drivetrain durability are the priorities, the Impact Derby 15 Bolt is our top-tier demolition derby rear-end package.

Built around the massive GM Corporate 10.5″ gearset, our 15 Bolt combines a shaved case, 40-spline Moser Hobby Stock axle shafts, 1/2″ wall DOM axle tubes, CNC-machined billet-steel housing ends/axle savers, extensive bracing and a complete pinion-brake package into one purpose-built rear end.

The result is a rear end designed to provide the strength of the drivetrain while gaining approximately 2″ of additional ground clearance for demolition derby use.

Built From a New Casting

Unlike a rear end built by starting with a used factory housing, the Impact Derby 15 Bolt starts with a brand-new center casting.

From there, we build the housing specifically for demolition derby use with new 1/2″ wall DOM axle tubes. Starting with a new casting allows us to build the housing from the ground up rather than working around the condition and limitations of a used OEM housing.

The result is a purpose-built foundation for the rest of the 15 Bolt assembly.

Shaved for Ground Clearance

The 15 Bolt gets its name from the modifications made to the traditional GM Corporate 14 Bolt design.

Approximately two inches are removed from the bottom of the case to substantially improve ground clearance. The internal components are machined as required to package the massive 10.5″ gearset within the modified housing, and the bottom of the case is reconfigured and closed with a fabricated plate.

Once complete, 15 bolts remain to attach the rear cover—giving the 15 Bolt its name.

This allows us to retain the strength and capacity of the 10.5″ drivetrain while gaining the ground clearance needed in a purpose-built demolition derby rear end.

CNC-Machined Billet Housing Ends / Axle Savers

The housing is finished with our CNC-machined billet-steel housing ends/axle savers.

Rather than relying on a fabricated tube-style axle saver, these components are machined from billet steel and designed around the massive 40-spline Moser Hobby Stock axle shafts used in the 15 Bolt.

The Moser axles are paired with bronze axle-shaft bushings and heavy-duty retainer plates to complete the axle package.

Built and Braced for Demolition Derby

The housing receives extensive protection and reinforcement, including a full truss brace tied into the top and back bracing, lower skid protection and a fabricated 3/8″ thick rear cover.

Suspension mounting includes precision-jigged 3/4″ upper trailing-arm ears, heavy-duty coil/leaf lower mounts and threaded coil spring perches.

A pinion brake, billet yoke and pinion-brake protector complete the package.

The rear end is assembled with a new full spool, new bearings and the gear ratio of your choice.

Once assembled, every complete 15 Bolt is filled with fluid and broken in before leaving our shop—ready for punishment.

Standard Build Includes

• New center casting
• New 3″ OD × 1/2″ wall DOM axle tubes
• Shaved case providing approximately 2″ of additional ground clearance
• 40-spline Moser Hobby Stock axle shafts
• Bronze axle-shaft bushings
• Heavy-duty axle retainer plates
• CNC-machined billet-steel housing ends/axle savers
• Full spool
• Gear ratio of your choice
• All-new bearings
• Pinion brake and billet yoke
• Pinion-brake protector
• Lower skid plate
• Full truss brace tied into the top and back bracing
• Heavy-duty coil/leaf lower brackets
• Precision-jigged 3/4″ upper trailing-arm ears for your application
• Threaded coil spring perches
• Fabricated 3/8″ thick rear cover
• Fluid and complete break-in before delivery

Optional Upgrades

• 10-lug bolt pattern
• Removable upper-ear top plate