What Are Tire-Balancing Beads, Do They Work, And How?

Balance beads are an interesting low-tech way of balancing your wheels, albeit only when they’re moving. If you’ve heard of them before, you might wonder what they look like when they’re sloshing about inside a tire. Or maybe you’ve never heard of balance beads before today, like me! Fear not. We’re going to explain everything.

Balance beads are literally just small temperated glass balls that you insert inside a tire. They’re designed to be large enough not to fall inside the valve stem, but small enough that they’re lightweight and able to easily flow around inside the tire. The idea is that in the course of normal driving, the beads will bounce around inside the tire and end up in the right position to counteract any imbalances in the wheel.

Before we get into how they work, let’s see them in action first. In a new video on the Warped Perception YouTube channel, we get a look at these beads as they’re rolling around inside a tire.

Beady Eye

The video gives us a great look at what goes on inside the tire. With the GoPro mounted on the wheel rim, we can see the balance beads collecting in a heap when the vehicle is at rest. Then, as the vehicle accelerates, the beads slosh around the tire, before distributing themselves on the tire wall.

So how are balance beads supposed to work? As you see in the video, the wheels rotate as the vehicle accelerates, and the beads eventually end up on the tire wall courtesy of centrifugal force (no arguments please). So far, so good. But that would just distribute the beads evenly, right? How does that counteract a heavy spot on the wheel and balance it out?

The answer to that lies in the action of the vehicle’s suspension. Imagine the wheel has a large heavy spot on one side. When that heavy spot is at the top of the wheel, it’s essentially tugging the wheel up due to the forces involved. Since the wheel is suspended, it can move upwards to some degree. The beads, however, are not affixed to the wheel. As the wheel moves up due to the imbalanced spot, the beads don’t follow. They float in space continuing on their original trajectory until they come back into contact with another section of tire wall farther from the heavy spot. This action goes on continuously as the wheel rotates, with the perturbations due to the heavy spot growing smaller as the beads redistribute to oppose it. Relatively quickly, the beads tend to congregate in a position that balances out the heavy spot, which quells any unbalanced movements that would redistribute them further.

A more obvious demonstration can be seen in this video. It’s a demonstration of DynaBeads (a brand of balancing beads) acting to balance out a spinning water bottle. You can see the bottle starts out heavily unbalanced, with the beads quickly redistributing in turn. Within seconds, the bottle spins quite smoothly with the vibrations all but gone. Naturally, when the rotation bottle stops, the beads fall loosely to the bottom of the bottle.

Ideally, we’d see this action more clearly in the video from Warped Perception. In an extreme case, we’d see the beads almost entirely leave the field of view. That’s because the weight of the GoPro inside the wheel significantly unbalances it, given it weighs on the order of 5 ounces. Thus, you’d hope to see the beads all flock to the other side of the tire to counteract this. This could just be because the beads don’t work quite as well as the manufacturer says they do, and they’re more prone to simply sticking to the outer wall rather than jostling into the right position.

Alternatively, there could be a lot more beads out of shot than we imagine, which are doing the job of counteracting the imbalance from the GoPro. To get a better idea of what’s going on, it would be ideal to do a similar shoot again, but with the tire given a large unbalanced weight on the opposite side to the GoPro. Then it could be determined if the beads are countering that weight by moving to the GoPro side under those conditions.

While much of the video concerns street driving, there’s also a section where the wheel is tested on a balancing machine. It’s worth noting that as the balancing machine holds the wheel stiffly on a fixed axis, little to no redistribution of beads will occur once they’ve found a position on the outer wall inside the tire.

Doing It Yourself

Balancing bead suppliers like Innovative Balancing or Wurth recommend using the beads in everything from motorcycle tires to those on big rigs or RVs. Typically, it’s recommended to use just 1 or 2 ounces of beads per tire for motorcycles. For cars, four ounces per tire is a typical starting point, while heavy trucks or off-roaders might use more than 10 ounces per wheel to help balance large, chunky off-road tires.

Notably, though, some companies don’t sell balancing beads for cars or SUVs. In the case of Innovative Balancing, the company says this is due to the common use of low-profile tires. The company notes these tires often require balancing in the lateral direction which the use of balancing beads can’t readily achieve. The company does suggest that eager buyers can still use the beads, but they should only be used in addition to traditional balancing with stick-on wheel weights. The beads are also not recommended for use “in any vehicle used for racing, for any application involving cornering at high speeds, or in tires placed under high acceleration beyond normal highway use.”

While you could theoretically just add a whole load of beads to your wheel and they’d presumably balance out, it’s a poor idea. You’re adding unsprung weight which reduces your suspension’s ability to control the wheel for a start, and the added weight won’t help your fuel economy, either. Despite this, multiple bead manufacturers suggest fuel economy as a benefit of their beads due to things like ”

Adding beads can be done in several ways. You can dump them inside the tire when installing it on the rim, or you can pop a bead and shovel them in that way. Alternatively, some companies provide tools to help you squirt them in through the valve stem – after removing the valve core, of course. However, this can be fussy and time-consuming, particularly if you’re adding a lot of beads.

I’m not entirely convinced that balance beads are a great balancing solution. I don’t love the idea of a bunch of beads rolling around inside the tire, even if they’re round enough that they’re not chewing up the rubber from the inside out. Plus, installation is fussy enough that it doesn’t seem much easier than just getting a shop to do the job properly in the first place.

With that said, the video above has intrigued me enough to want to test them for myself. Maybe one day I’ll head out on the road with an unbalanced wheel and a barrel of beads and see what I can find out. In any case, if you’re on Team Bead, let me know your experiences with these oddball glass balls. I’d love to know if they make a big difference in the real world – or not!

Image credits: Warped Perception via YouTube screenshot, Innovative Balancing, Cruiseman’s Garage via YouTube Screenshot