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Trailer Tire Balance Is Crucial
If you want a high-yielding crop, that quest begins with a soil test. If you want high-yielding tires, that journey starts with having your tires balanced to get the most reliability from the vehicle or trailer. Many think of tire balance as strictly for ride comfort, but there is much more going on as any tire rolls down the road.
Though it is commonplace to have car and truck tires balanced, it is just as important to balance those on trailers if they’ll be driven at 30 mph or faster.
When a wheel rotates, any difference in mass creates the desire for the heavier area to want to move away from its axis of rotation – or, in other terms, be flung out. It needs to be recognized that as a tire rolls down the road, it does not stay completely round.
As the portion of the tread contacts the surface, it flattens out as the weight of the vehicle is placed on it. Then, as that part of the tire rolls away from the surface, another contact patch undergoes deformation. Though an exaggerated image, just think of a tire that is very low on air. In this case, the bottom is flattened while the rest of the tire is round. To a lesser extent, this is what happens to every tire as it rolls. For this reason, inflation pressure is critical since it not only supports the weight of the load but also limits the amount of tread that flattens as it rolls.
When the rotating mass of the wheel and tire assembly is out of equilibrium, then it wants to hop, wobble, and bounce. As the road speed is raised, these actions increase and magnify. I think this is understood, so I want to bring the discussion to a higher level. I also want to establish that you need to balance trailer tires since the dynamics of rotational imbalance affect them – even though you may not feel it.
Just as a nutrient deficiency in a crop has already caused a yield loss by the time it is visual in the plant, by the time a tire vibration reaches your senses, it is degrading many components.
Out-of-balance tires cause excessive wear in wheel bearings, suspension parts, spring shackles, shock absorbers, and the tires themselves. The tire may experience cupping, uneven wear and tread, or ply separation. This is especially true with trailer tires. Trailers will also bounce more when unloaded, shake themselves apart, and transmit that motion into the hitch and the tow vehicle. As it pertains to an emergency braking situation, a properly balanced trailer tire will decrease the stopping distance and provide much better control.
tips for balancing
New tires should always be dynamically (spun) balanced – if possible, on a machine that provides a road force test. This is where a roller is pressed against the tire to simulate the deformation that occurs when in use. There is an effect identified as radial force runout that allows a tire to bounce down the road even though it is in mass equilibrium.
As a tire wears, it will impact the balance. At one-half tread life, I like to get tires rebalanced. The cost of balancing is very low, and it provides better driving dynamics, decreases wear on the tire and vehicle or trailer, and improves safety.
A good technician will acknowledge the amount of weight required and then, if excessive (more than 2 ounces on one side), will break the bead and rotate the tire on the rim 90° and then retest. This process is repeated until the least amount of weight is required.
When tires are new, they have a paint or ink dot to identify the mounting in relation to the valve stem. If you see a wheel loaded with lead weights, then either the mechanic that balanced it was poor, the machine was out of calibration, the rim bent, or the tire is not well made.
I also like to carry with me a tire crayon. If I get a flat on the road, I can mark the position of the valve stem and the weights so the tire can be put back on the rim in the exact location, if the shop fixing it doesn’t have a balancer I feel comfortable with.