US Gear recently announced it will sell off-the-shelf gear sets with Isotropic Superfinishing (ISF) treatment. For many, this news begs the question:

What the heck is Isotropic Superfinishing?

For those of us who spent high school science class playing paper football and doodling in our Trapper Keeper, the concepts of isotropy and isotropic finishes is a bit of a foreign topic. Essentially, isotropy means uniformity in all directions; therefore, isotropic finishing is the process of creating a uniform finish on a surface.

So how does the ISF process work?

The Isotropic Superfinishing process consists of two steps.

The first step in the ISF process is referred to as the refinement process. It involves a chemical interaction that forms a soft, thin film (no more than one micron) on the surface of the gear. As the gear interacts with the non-abrasive ceramic media in a special vibratory tub, this film is physically removed from the peaks of the processed part while the valleys are unaffected. The film then re-forms at the peaks that are interacting with the vibratory media. This process of film re-formation and removal repeats itself until the peaks are gone and only the valleys are left. This results in a smooth micro-finish.

The second step in the process is referred to as burnishing. During this stage, all of the remaining conversion film is removed from the surface of the gear, leaving a polished, chrome-like appearance.

You can get a better look at the process by watching this video:

What are the advantages of Isotropic Superfinishing (ISF)?

Although it leaves a polished finish, it’s important to note the ISF process does not simply polish the gears. ISF offers several advantages over traditional finishing processes like polishing, coatings, and even cryogenics. Its inherent use of vibratory finishing methods removes stress risers produced during the manufacturing process and creates optimum surface roughness. The smooth, uniform (isotropic) finish created by ISF fosters increased lubrication retention and heat transfer.

Proponents of Isotropic Superfinishing tout these key benefits:

  • Reduced surface stress
  • Reduced friction, vibration and noise
  • Longer component life
  • Reduction in lubrication temperature
  • Increased heat transfer
  • Mirror-like finish


The gear set on the right shows the mirror-like finish of the Isotropic Superfinishing treatment compared to a non-finished ring and pinion.

According to US Gear, the ISF process also eliminates the typical gear break-in procedure. The company is such a believer in ISF treatment that it had REM Surface Engineering super-finishing equipment installed at its facility in Troy, MI. This equipment is used to provide in-house surface finishing for all of US Gear’s high performance racing gears. This has eliminated one of the traditional drawbacks to ISF treatment: wait times.

In the past, racers would ship their gears out to receive ISF treatment and then wait for them to be finished and shipped back. With the launch of US Gear’s new Lightning Series Ring and Pinion Gear Setsthese racers can now buy ring and pinion sets with ISF treatment right off the shelf.

“Since the product is factory finished, we can provide our customers with a faster turnaround and eliminate an extra step which adds additional shipping costs,” said Tim Goode, US Gear’s Director of Sales, North America — Off-Highway & Motorsports.

You don’t need to be a science whiz to be excited about that.

Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.