Rolling Down The Highway: How To Mount & Balance Wheels & Tires
Wayne Scraba
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Have you ever really considered what it takes to mount and balance wheels? In a past life, the writer had a speed shop. We sold plenty of aftermarket wheels and tires. And invariably, we’d come across wheels that were damaged (after the sale) by improper mounting. We’d also encounter balance issues caused primarily by a lack of knowledge. The truth is, not all shops can properly mount and successfully balance aftermarket wheels and big tires.
In the photos that follow, you'll see how a pretty common BF Goodrich Radial TA is mounted on an aftermarket aluminum wheel. A new wheel from the folks at Real Rodder Wheels was used as an example, but in many cases, an enthusiast will bring in a used wheel. BF Goodrich mentions that all used wheels that are about to be mounted should be cleaned. You'd be surprised how many wheels are actually covered in rubber debris and dirt. Not only is it tough to mount a tire on such a wheel, it makes balancing difficult. Tires should be kept clean too. Use a common tire cleaner or protectant such as Armor All. Never use a brake-cleaning chemical on tires. BF Goodrich also points out that you should remove all old weights along with any tape used to cover the weights. It's also easier for technicians to handle tires that aren't flat. When returning rolling stock for a re-mount, keep the tires full of air.
For a closer look at how the pros mount tires, check out the following (we’ll this up with a second part in an upcoming segment):
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The wheel used in our example is the Real Rodders Wheel we showed in the last issue. The BF Goodrich tire we're using is usually operated tubeless. In this photo, the technician is installing a valve stem.
The tire used in the example is a BF Goodrich Radial TA. The tire is designed for use on wheel width ranging from 8 to 10-inches. Before mounting, the bead on the tire along with the inside of the wheel should be coated with a lube of some sort. Here, PREMA “Euro Paste” mounting compound is brushed on. This paste is designed to reduce bead damage and at the same time, helps to eliminate rim slippage (tires turning on the wheel rim). It doesn’t freeze or harden either. The third benefit of using this stuff is the ability to inhibit rust.
Many tire lubricants are water based and if the solution doesn’t include corrosion inhibitors, corrosion will develop on the wheel in the tire bead area. This corrosion will build up and can eventually cause the tire to leak between the bead and rim. Also, the corrosion can cause a form of "welding' between the tire bead and the wheel making it very difficult to break the bead when the tire is dismounted later. Using unusual force to break a bead may cause bead damage. By the way, some shops still use a mix of soap and water. What type of soap is used? That's easy. Good old-fashioned liquid dish detergent.
The next step involves installing the tire over the wheel.
It's common practice to install the backside first, followed by the front side or face side of the wheel. There's nothing fancy here, but care is taken not to damage the wheel or the tire.
At this point, the core is installed in the valve and the tire is aired to a maximum of 40 pounds per square inch to seat the bead to the wheel rim. If the bead doesn't seat at that pressure, then the tire should be broken off the rim and re-coated with soap or mounting paste (in essence, you have start from the beginning again). The use of excessive air pressure when mounting tires isn't a good idea. Once the tire has seated, reduce the air to the approximate intending running pressure. In this case, it's set at 35 pounds per square inch. Keep in mind vehicles fitted with non-stock wheels and tires don’t have exact pressures you can use. Each car will mandate how little or how much pressure is required. It’s usually a matter of trial and error.
