tyre question

Ash

Ex. Club Member
I got myself a couple of new tyres today just normal everyday ones and there are three stripes of colour red, yellow and white round the tread bit of them. Might be a silly question but wondered if anyone knew why they have this
 
Aw, thanks. I thought it might be something to show that they were new and hadn't been used before of something like that.
 
http://www.chris-longhurst.com/carbibles/tyre_bible.html

Often when you buy tyres, there will be a coloured band or stripe running around the tyre inside the tread. These can be any colour and can be placed laterally almost anyhwere across the tread. Some are on the tread blocks whilst others are on the tyre carcass. For ages I thought this was a uniformity check - a painted mark used to check the "roundness" of the tyre. But I had a tyre dealer contact me with a far more feasible answer. The same tyre is often made with slightly tweaked specifications for different vehicles. To easily identify these same labelled tyres when they are warehoused or in storage, different markings and stripes are used. Sometimes stripes are added for huge bulk orders to various manufactures. Eg All the red outside stripes are for Toyota next week. This gives anyone in the warehouse a very quick visual check of the different types of tyres without needing to pull them all down and read the sidewall on each one.
As well as the colour, the actual position of the lines is something to take note of too. They're a measure of something called runout. Depending on how the belts are laid on the tyre during manufacturing, they can cause the tire to "run out" - to not track perfectly straight, but pull to the left or right. The closer to the centre of the tyre that these lines are, the less runout the tyre has and the straighter it will track when mounted on your car. So for example, if you were looking at your car from the front and you saw the coloured striped running around the right side of both your front tyres, the car would likely have a tendency to pull to that side. The best thing is to have the coloured stripes on opposite sides of the tyres for opposite sides of the car, so that the runout on each side will counteract the other and help maintain a good straight running. This is something that not many tyre fitting places know about or take any notice of. The obvious solution to having the stripes both on one side is to flip one of the tyres around, but that will only work if they're not unidirectional tyres. If they are unidirectional (and thus must be mounted to rotate a specific way) then you should try to find another tyre from the same batch with the stripe on the opposite side.
 
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