Strange days in 4WD competition build projects

The old Ford nine-inch is still the benchmark

In rodding, racing, off-road racing, 4WD trials and the epic King of Hammers off-road motorsport events, Ford’s legendary nine-inch differential remains the standard to be measured by.

Among the many, many companies selling competition-specific nine-inch diffs, US-based Strange Engineering has the biggest, strongest Ford nine-inch rear end.

It has heritage. Ford produced this famous rear axle from 1957 through 1986 for road use, and izt’s been installed in nearly every Ford passenger car and truck. In racing and off-roading these rear ends and their aftermarket descendants are everywhere.

All widths, all types of ‘centres’, air lockers, mechanical limited slip units, the nine-inch is everywhere. Any mechanical product that can last 65 years in motorsport has some serious credibility.

Strange is one of the leading names making these things; selling axles and housings to suit any application.

The best thing: it’s off-the-shelf gear, available online and freighted to every country that has high output, high torque motorsport.

In other words, pay for the gear and it arrives fully built and crated for travel.

One of the key design aspects of the diff that makes it popular in motorsport is how the ring and pinion gear is accessed. It allows for the pinion side, centre section to be removed. This includes the centre case, the pinion gear, the ring gear, and the differential or spool.

Too technical? It simply means the diff can be dismantled, serviced and reassembled faster. An advantage in motorsport and also in the workshop.

Strange Engineering has designed improvements to nine-inch rear ends to accommodate trends and changes in motorsport. The company has increased the strength of the unit: Strange nineinch rear ends are constructed of .141” mild steel with a heavy-duty .282” face plate. The company also made a heavy duty diff of .125” alloy steel with a heavy-duty .375” faceplate. When paired with a back brace, this housing provides the ultimate in strength and reliability.

A number of Kiwi triallists and offroaders have used Strange diff units, axles and diff centres over the years. More are using the diffs today in ever more innovative designs; the upgrades coming as 4WD sport (trials, off-road racing, the mad and messy mud drag fraternity) turns more and more to high output V8 power.