Diversified Machine

Diversified Machine Inc. (DMI): American-Made Racing Components Built to Win

Diversified Machine Inc. (DMI) is one of the most respected names in short-track and sprint car racing. Founded in 1991 by Jim and Tammy Haines in a modest two-car garage in Lancaster, PA, DMI began as a precision machine shop before Jim — a certified tool and die maker — discovered sprint car racing in the mid-1990s and redirected the company's focus toward high-performance motorsports components.

That pivot proved transformative. From those humble beginnings, Diversified Machine has grown into a state-of-the-art manufacturing facility housing 14 CNC machining centers, including five live tool lathes, all dedicated to producing the DMI and Bulldog product lines. Today, the company is run by Dave Ely, a former URC Sprint Series Champion and National Sprint Car Hall of Fame Driver of the Year Nominee — a racer who brings genuine on-track experience to every product decision DMI makes.

The DMI & Bulldog Product Lines

DMI's catalog covers the full spectrum of sprint car driveline, steering, and suspension needs. Their signature offering — the Bulldog Quick Change Rear End — has become a dominant force across multiple racing disciplines. Bulldog rear ends have powered cars to 17 consecutive USAC National Championships and have long dominated the Northeast Dirt Modified market. The Bulldog line features aircraft-grade magnesium castings for exceptional strength-to-weight ratio, and the innovative EZ Series side bells that simplify trackside gear changes.

Beyond the Bulldog rear ends, DMI torque tubes are essential driveline components for midget and sprint car builders, crafted from high-strength 2024-T3 aluminum in multiple lengths for precise fitment. For chassis tuning, DMI torsion bars — including their T-Rex line — are machined from chromoly steel to exacting race specifications, giving teams reliable spring rates they can count on night after night.

Keeping all of those high-performance components properly lubricated is just as critical as the hardware itself. DMI's racing gear oil is specifically formulated for the demands of quick-change rear ends and driveline components operating under the extreme loads of sprint car competition. The brand also offers engine oil drain plugs and related hardware accessories designed to complement their rear end and drivetrain components at the track. Rounding out their driveline ecosystem, DMI suspension bearings — including their CT-1 side bell bearings and rear end bearings — are precision-machined to maintain proper alignment and reduce friction in the most demanding racing environments.

Why Racers Trust DMI

What sets Diversified Machine apart is not just the quality of their parts, but the culture behind them. DMI is run by racers, for racers. Owner Dave Ely personally handles a significant portion of incoming sales calls, applying his 20-plus years of open-wheel racing experience to help customers choose exactly the right components for their setup. Whether you're a weekend warrior at your local dirt track or a professional competing at the highest levels of sprint car racing, DMI and Bulldog components are engineered to perform when it matters most.

• Manufactured in the USA with state-of-the-art CNC precision
• Bulldog Quick Change Rears dominant across USAC, dirt modified, and drift applications
• Full driveline ecosystem: torque tubes, torsion bars, bearings, gear oil, and accessories
• Expert technical support from experienced racers
• Trusted by championship-winning teams from the Chili Bowl to IRP