To people like us, visiting a tyre shop is almost like being a kid in a candy store. There are just so many things to see and so many things going on that we can’t help but get excited. If you’re like us and have been paying close attention when your tyres are being fitted, you might have noticed that some of these new tyres have a few coloured dots on the side wall. Most of us just chalk it off as a leftover mark from the manufacturing process, but they actually serve a pretty important function!
So what exactly are they? Usually found on the side wall in yellow and red, these dots are commonly known as balancing dots in the tyre industry. As the name implies, they help the technicians to ensure that the wheels are as balanced as possible, while using the minimum required balancing weights.
The Yellow Dot – Weight
Most manufacturers use a yellow dot to mark out the “light static balance point” of the tyre, although there’s no standardised colour for this purpose. In simpler terms, these dots represent the lightest point in terms of weight of the tyre, as they are never manufactured to pin-point accuracy.
By lining up the yellow coloured dot with the valve stem on the wheel, the weight distribution across the entire fitted wheel will be more balanced, thus requiring less lead weights to properly balance the wheel, and therefore resulting in a smoother and quieter ride, while also extending the life of your tyres.
However, thanks to the improvement in manufacturing of newer alloy wheels, the valve stem placement has evolved to being more of an aesthetic consideration over weight distribution, so yellow dots might not necessarily be the most accurate way of “harmonising” the new tyres to your wheels.
The Red Dot – Uniformity
Just like how the tyres are never perfectly balanced, they are also never uniform in shape (roundness), with peaks and depressed spots at the joints of the multiple layers of belts within the tyres. If left unaddressed, the high points will result in vibrations in the cabin.
The red coloured dot marks out the highest point in the tyre, or the “radial force variation first harmonic maximum” – where the centrifugal forces are at maximum on a rotating tyre. In most cases, your wheels will also have a dot – either drilled or marked out by sticker – to signify its lowest point. The red dot on your tyres should then match up with this marking on your wheel.
This is the most accurate method to optimise your tyres for your wheels, and that’s why they have a standardised red dot marking across the industry! If your wheels have its low points marked out, definitely follow the red dot instead of relying on the yellow dot.
Red over Yellow
In the event that you have both yellow and red dots on the tyre, but no marking on your wheels, the red dots should take precedence over the yellow in lining up with the valve stem, due to the reasons mentioned above; weight balance can always be rectified with balancing weights.
So that’s it! The next time you fit new tyres at the shop, you’ll know what the technicians are doing with these dots, or even show them a thing or two if they’re not in the know! Ensuring that your tyres are properly balanced means that they are running better, and remain running for longer, saving you money in the long run.
While you’re here, also check out how your tyres look from the inside while you’re driving down the streets!
[Images: Tyrepower Blackwood]