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While buying used tyres I checked the dates stamp on them and found some looked to be doctored.

The date stamp on nearly all the tyres was in raised lettering. But on some tyres the date lettering was indented, as if stamped on.

It was as if someone sanded down that part and then stamped new date values on.

Do you think these tyres were dodgy? or am I just reading too much into it?

My question really is, is the lettering on tyres always in a standard format? Should all lettering on it be 'raised'?

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    Different brands are going to have different ways of molding the date into the tire. Also, the rubber of a tire is treated after it is molded and after the treatment process, you won't be able to engrave or stamp anything in the rubber the same way. – JPhi1618 Sep 15 '17 at 19:15
  • you are probably the one person in a hundred who even bothered to look at the date code. It seems it would be almost pointless to fake the date. – agentp Sep 17 '17 at 12:29
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While this is an international site, I can only answer for the region of the world I live in (USA).

Here the Department of Transportation (DOT) has specific requirements for the date codes, but the manufacturers are allowed to use whatever codes they prefer.

enter image description here

Tire since the year 2000, the last four digits indicate the week and year of manufacture. In the image above, the tire was made the 51st week of 2007.

enter image description here

Prior to 2000, they used a number that equated to the week and year within the decade. For instance, 408 would be the 40th week of the 8th year in that decade.

What I am unable to answer is what the local laws and regulations for tire manufacturers where you are located. As tou can see, these are molded into the tire.

Source

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  • So the date letters can be indented, with the rest of them raised, interesting. I didn't notice any screw markings around them, and the the numbers didn't line up as nicely as in your image, but I guess I was being over paranoid. – centerback Sep 18 '17 at 10:23
  • As stated, it all depends on the manufacturer, their processes and regulations they are under. – CharlieRB Sep 18 '17 at 11:41
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If they look "doctored" then don't purchase them.

I would not purchase second hand tyres anyway as, while they may look ok, you don't know if they were kerbed or have suffered internal damage...

Once I factor the cost of fitting and balancing, the total cost of new tyres and the life I get (two seasons for winter ones) makes any secondhand option seem not worth it IMHO...

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From a manufacturing point of view it's way easier to have the changing numbers be stamped instead of having the numbers changed in a mold. So I can imagine quite a few tire manufacturers stamp the date instead.

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    The mold has a replaceable insert where the numbers go. Changing the numbers is just a matter of replacing a small plate or similar inside the mold. The images in CharlieRBs answer even show the screw heads of the plate molded into either side of the date plate. – JPhi1618 Sep 15 '17 at 19:13
  • Makes a lot of sense, thanks for the insight! – Elias Sep 17 '17 at 19:26
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I'm not aware of any requirements for them to always be raised but I must say that I don't think I've ever seen any where it was indented rather than raised. I would definitely expect it to be consistent across tires of the same make/model.

To my mind you can't be too careful when it comes to this sort of thing so I would walk if it didn't "smell right".

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