Is a Road Force Wheel Balance Necessary?

We get asked about road force balancing pretty often, especially when customers are comparing wheel balancers or trying to solve a vibration that a normal balance hasn't fixed.

The short answer is:

Not every wheel needs a road force measurement, but diagnostic wheel balancing can be extremely useful when a traditional balance doesn't tell the whole story.

And now there is more than one way to approach that diagnosis.

A Balanced Tire Can Still Cause a Vibration

A standard modern wheel balancer measures weight imbalance in the tire and wheel assembly.

If one area of the assembly is heavier than another, the balancer tells the technician where correction weights need to be added.

For most normal tire service, that works very well.

But balance isn't the only thing that affects how smoothly a tire rolls.

A tire can be properly balanced and still have:

• Radial runout
• Wheel runout
• Variation in tire stiffness
• A tire and wheel combination that isn't matched particularly well

Those conditions can create a vibration even when the balancer shows the assembly at zero.

That's where diagnostic balancing comes in.

What Is Road Force Balancing?

Hunter's Road Force system uses a roller that applies load to the tire while the assembly rotates.

That allows the machine to measure radial force variation under load, which can help identify conditions caused by the shape of the tire, wheel runout, and variations in tire stiffness.

It can also help determine whether rotating the tire on the wheel may improve the assembly.

Road Force has become so well known that people sometimes use the term to describe any wheel balancer with a diagnostic roller.

Technically, though, Road Force is Hunter's specific system.

Coats Now Has Another Diagnostic Approach

Coats recently introduced the ProBalance E900, which adds diagnostic capability to its wheel balancing platform.

The E900 uses a diagnostic roller to measure radial tire runout while a laser measures rim runout.

Its ProMatch system can then guide the technician through repositioning the tire on the wheel so the high point of the tire is better matched to the low point of the rim.

The goal is to reduce the total runout of the assembled tire and wheel.

That can help solve vibration problems that simply adding or moving wheel weights will not correct.

Is the Coats E900 the Same as Hunter Road Force?

No.

They are trying to solve some of the same real-world problems, but they do not perform exactly the same measurement.

Hunter Road Force measures radial force variation while the tire is under load.

The Coats E900 measures tire and wheel geometry, including radial runout, and uses that information with ProMatch to help optimize how the tire and wheel are assembled.

Both give the technician information beyond a normal balance.

They just approach the diagnosis differently.

Does Every Shop Need a Diagnostic Balancer?

Probably not.

If you're a general repair shop doing occasional tire work, and your customers rarely come in with difficult vibration complaints, a quality conventional wheel balancer may do everything you need.

But diagnostic capability becomes much more valuable when tire work is a significant part of the business.

That includes shops that:

• Perform a high volume of tire service
• Regularly work on newer vehicles
• Install low-profile or performance tires
• Work with larger wheel and tire packages
• Deal with recurring vibration complaints
• Want to reduce tire-related comebacks

In those situations, knowing that a wheel is balanced is only part of the picture.

Being able to identify why a balanced assembly still isn't rolling smoothly can save a technician a lot of time.

Don't Forget the Basics

No diagnostic system can compensate for poor mounting technique.

The wheel still needs to be properly centered on the balancer.

Cones, collets, pressure cups, the balancer shaft, and the wheel mounting surfaces need to be clean and in good condition.

If the wheel isn't mounted correctly, even an expensive diagnostic balancer can give you information about a problem that you created on the machine.

Start with the basics.

Then use the diagnostic tools when the basics don't explain what you're seeing.

Which Type of Balancer Makes Sense for Your Shop?

That depends on the work you actually do.

A shop that changes a few sets of tires each week has very different needs than a dealership or tire store installing tires all day.

We don't think every shop needs to buy the most expensive balancer available.

But if tire-related vibration complaints are costing you technician time or creating comebacks, diagnostic capability can absolutely be worth having.

The introduction of the Coats ProBalance E900 gives Coats shops a new option for adding that capability without pretending that every balance needs to become a science project.

Northcoast Equipment Specialists provides Coats wheel balancer sales, installation, and service throughout Northeast Ohio. If you're comparing balancers or aren't sure whether diagnostic balancing makes sense for your shop, contact us and we'll help you determine what fits the work you're actually doing.