# How reliable are bubble balancers?

I'm starting down the DIY-automotive path and was reading about how some people use bubble balancers to balance their own tires at home. Can anyone speak to the accuracy of these balancers? Does anyone use them, and if so, how you found them to be precise enough for everyday use?

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Long before the spin balancer was invented all tires were balanced by a bubble balancer. If done properly, the 4 point static balance is as good and accurate as any other method.

The most effective bubble balance is accomplished on both inner and outer portions of the tire rim. This is called a 4 point balance, and can be accomplished as fast as any dynamic balance. To statically balance a tire using a bubble, the outer edge locations are determined by centering the bubble with 2 weights at the outer side of the rim. Once the weight is determined these 2 locations are marked on both inner and outer sides then the weight used is divided by 2 and the inner side has half of the weight of the outer side. As an example 2 one ounce weights placed on the outer edge of the tire center the bubble. These 2 locations are marked with chalk, and the bottom of the tire is also marked so when it is turned over the mark will show where to place the weights on the inside of the rim. This creates 4 half ounce weights hammered into position, 2 on the inner rim and 2 on the outer rim.

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The race team that I buy my tires through (they do periodic group buys), will do free mounting and balancing with a bubble balancer. I've taken advantage of that before and have no complaints. Couldn't tell any bit of difference between a set of tires dynamically balanced and those bubble balanced. The only apparent downside was that it took longer to do the balancing process with the bubble balancer vs. a dynamic balancer.

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A bubble balancer is only able to balance the tire in one plane, as if it were a flat disc. A dynamic balancer is able to detect and correct for balance in both that plane as well as the axial dimension. You'll notice that wheels balanced on a dynamic machine often wind up with weights added on both the inside and outside of the rim.

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