Trailer Tires: To Balance or Not to Balance?

A tire balancing machine.

Is it necessary to balance trailer tires? Is it an unnecessary expense? Like many complicated issues, the answer is that it all depends. Since the primary duty of a trailer tire is supporting a vertical load, rather than gripping an automobile through turns, trailer tires do not have to be dynamically balanced like passenger car tires do. Steering and cornering are less of a concern on a trailer tire than they are on an automotive tire. Balanced passenger car tires prevent the passengers inside a vehicle from feeling the bumps and irregularities of the road at higher speeds. Although some trailer cargo requires the smoothest of rides, trailers transport cargo and equipment, rather than passengers, so the standard for ride quality is usually less of a concern.

The Challenges Associated with Balancing Trailer Tires
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Trailer owners may struggle over the long haul to keep trailer tires balanced because their wheels tend to "throw weights." In other words, the tire balancing weights end up coming off of the trailer wheels during normal trailer usage, which can happen for a number of reasons. It is not uncommon for the weights to be thrown off when towing an unladen trailer because the trailer may bounce excessively without a load, especially through potholes and over rough terrain. Tandem or triple-axle trailers tend to throw weights when making tight turns as well.

Another aspect that makes balancing trailer tires challenging is that most automotive service centers are not equipped with the proper wheel balancing machine to correctly balance most trailer tires. Most trailer wheels are a lug centric design which means the wheels are centered on the hub by the torque of the lug nuts. On the other hand, many automotive wheels are a hub centric design. Most automotive service centers use a computerized "cone" balancer which works great on automotive hub centric wheels, but does not work very well on lug centric trailer wheels. In order to correctly balance trailer wheels, an adapter must be used on the cone balancer. To save time and avoid a wasted trip, customers should check with their automotive service center beforehand to make sure the company has the adapter to properly balance trailer tires.

Further complicating the issue is the fact that many trailer wheels are galvanized, and galvanized trailer wheels are usually not designed to be balanced. When the steel wheel is hot dipped galvanized, some of the liquid zinc often accumulates on one end. This can make galvanized wheels difficult to balance. However, the upside of galvanizing is the galvanized coating provides corrosion resistance to harsh environments such as salt water. If end-users are not sure whether or not their trailer wheels are galvanized, they should ask their trailer manufacturer or wheel manufacturer, and follow the wheel manufacturer’s specific instructions on whether or not they should balance their tires and if so, how best to do so. 

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Tire beads on the inside of a tire are used to easily balance tires.

How does the Trailering Application Factor In?
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Customers purchase trailers for a wide variety of reasons, and the intended use of the trailer is a significant factor when deciding whether to balance the trailer tires. For example, recreational vehicle trailers and boat trailers are often stored outside in harsh environments. These trailers are typically only pulled on a handful of trips each year. Some customers will not balance tires on these trailer models because they feel the tire will wear out from dry rot long before the tire tread is actually worn or any substantial benefit would be derived from having the tires balanced.

​In addition, the size of the trailer and the type of cargo transported are other useful factors for determining if tire balancing is necessary for a specific trailer. Valuable, fragile cargo may be more protected and have a smoother ride with balanced tires. In addition, trailer cargo can have a rough ride if vibration and suspension components lend themselves to instability when the trailer is on rougher roads, or the trailer is improperly loaded.

Another trend in recent years is installing custom wheels on trailers, including chrome and aluminum. These wheels have an attractive look and are typically acceptable for each trailer as long as the trailer manufacturer or end-user makes sure the wheels have the correct weight capacity for their trailer, as well as the correct wheel offset, which will assist in making sure the load is over the hub bearings.

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An example of a tire weight used for tire balancing.

How do Wheels Factor In?
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Customers can have their trailer tires balanced if they wish, but it is not essential to the proper operation of most trailers. As was previously mentioned, there are two distinct types of wheels found on today’s cars and light trucks. Hub centric wheels are centered by the center bore of the wheel and hub flange. Most trailer wheels are lug centric and are centered by the torque of the lug bolts, rather than the center bore of the wheel and hub flange. The most common automotive wheels are hub centric in design. The center hole of these wheels are the actual center bore of the wheel. If new tires are purchased for a set of stock wheels, the customer can have them balanced if they choose. If the customer balances the tires, they must take into account that many trailer wheels are lug centric. To get the best tire balance for lug-centric wheels, the tires should be balanced by a shop that uses a pin plate adapter. This mimics the way a lug-centric wheel is mounted to a hub and will result in the best overall outcome.
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Many tire and wheel manufacturers balance tires by mounting their tire and wheel assemblies so the high, heavy spot on the tire is aligned with the low, light spot on the wheel. This provides adequate balancing for many trailer tires. Many trailer manufacturers purchase their tire and wheel assemblies mounted and inflated to PSI specifications from the factory. However, some do not, and it depends on the terms of the trailer manufacturer’s agreement with their tire and wheel supplier. Some end-users insist their trailer tires be balanced, but the majority of trailer customers are probably not concerned with whether or not the tires are balanced. Most end-users simply want their trailer to adequately perform its function. However, in some applications the end-user may not be aware that adequate performance for their particular trailer requires that the trailer tires be balanced or balancing the tires would greatly improve the ride quality of the trailer.

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