# ? About dot numbers on my tires



## Hitch Pin (Sep 23, 2011)

I posted earlier in another post about the tires on my new T T , as I said in the post they are Towmax 175/80R13 STR I looked on the tire to see where they are made and it dos not say.

I got the DOT numbers off of the tire, it is DOT 83B1 4310 GPB DY. Does anyone know what these numbers mean?


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## artmart (Sep 21, 2010)

The location a tire is made is a two character code following the "DOT" letters, or in your case, "83". This means they were made at Shandong Hengdeng Rubber and Plastic Co. LTD in China.

The date is the 4 numbers 4310 and they are stamped in after the tire is made since the date will vary. In your case, the date code shows the tires were made on the 43rd week of 2010 or sometime in late October, 2010 (They are approaching about a year old). 

Even though I posted the two most important parts of the DOT code you need to be concerned with, feel free to search the internet to find some internet links that describe how to read the rest of a tire's sidewall codes. You'd be surprised how much is there and how much you can use this to safeguard your next tire purchase. If you need help with this let me know and I'll try and post them in this forum.


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## Hitch Pin (Sep 23, 2011)

artmart said:


> The location a tire is made is a two character code following the "DOT" letters, or in your case, "83". This means they were made at Shandong Hengdeng Rubber and Plastic Co. LTD in China.
> 
> The date is the 4 numbers 4310 and they are stamped in after the tire is made since the date will vary. In your case, the date code shows the tires were made on the 43rd week of 2010 or sometime in late October, 2010 (They are approaching about a year old).
> 
> Even though I posted the two most important parts of the DOT code you need to be concerned with, feel free to search the internet to find some internet links that describe how to read the rest of a tire's sidewall codes. You'd be surprised how much is there and how much you can use this to safeguard your next tire purchase. If you need help with this let me know and I'll try and post them in this forum.


Thanks for the info. It's no wounder there's no jobs in the US, If a person needs a job, they could go to China, we must not know how to make anything in the USA anymore.


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## PhilnJill (Aug 3, 2011)

you can still buy American made tires. Dunlop is an American based company with plants all over north america. they also go by the Goodyear name.

Dunlop is the only American manufacturer of motorcycle tires. just a little trivia there.


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## artmart (Sep 21, 2010)

Even though we are starting to drift off topic, I will add comment on the latest post which helps understand why knowing how to read a DOT code is IMPORTANT.

I thought Dunlop was a UK company but they have factories in America since labor is probably the same so why worry about shipping costs. I don't know if they make ST tires, if that's what you want to put on your trailer. Other owners have such a distrust of ST tires they have made conversions to LT (light truck) tires, but in any case you must pay very close attention to the weight ratings.

Allegedly, Maxxis tires are also American made for trailers and are rated as some of the best ST tires available. Because of this they will be more expensive. You might still check the DOT code to confirm its manufacturing location, but then you'll need to bring a printout of the 900 codes for where tires are made around the world to cross reference exactly where.

Besides questional quality for trailer tires other causes are owner-based and prone to owner actions. The tires should be covered when stored to minimize sun damage from sitting so long, tires that sit too long in one spot will get flat spots from not moving, tires must be kept at proper inflation. Some owners even go through the trouble of putting their trailer on jacks at the frame to relieve pressure on the tires. Unfortunately storage is counter to how we treat our trailers since we don't use them often to keep the tire rubber supple and flexible. Then there's driving habits. I have not seen an ST (Special Trailer) tire with a speed rating higher than 65, but I have seen plenty of trailers being towed faster than that for long periods. Then of the unusual length of trailers many owners cut turns too soon and this can cause a trailer tire to go up onto a sharp curb or driveway and this cuts into the sidewall. Inflation is not checked each day and this is critical (I carry a compressor and reliable tire gauge for this on every trip).

Finally, there's the tire twisting that occurs with trailers because of the stance of the tire attached to axles that do not turn nor have a differential. Even a vehicles rear tires spin at different speeds via a "differential" on a turn to reduce wear and tear. A trailer's tires do not to this. Take note next time you are making a severe turn (forward or backward) and you will see the trailer tires no longer standing straight up and down. The tires will be positioned in wierd angles and you can only imagine the stress being put on the tire - sharper the turn the worse it is. It is very important to straighten your rig over enough distance so that the trailer tires reorient themselves prior to stopping or setting up your rig for a long time. Just drive straight forward or backward for some few feet and your trailer tires will love you for it that you don't leave them in this "stressed" position.

It has been suggested that tires be changed out every 5 years just because of the interior dry rot that occurs from tires that sit too much. This is one reason you must know how to read the DOT code. Plus all those other reasons I mentioned above that we might be doing to our tires.


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## PhilnJill (Aug 3, 2011)

don't intend to drift off topic but here is a little I copied to paste here. 

In 1888, John Boyd Dunlop took out a patent for the first pneumatic tire in history. His revolutionary tire design, which for the first time used a hollow rubber inflated with compressed air, grew over time into a major tire industry that, as of January 1, 2010, had the capacity to produce 320,167,050 tires, (excluding race tires) in North America alone. Headquartered in Buffalo, New York, Dunlop today operates for the most part under the Goodyear name
Read more: Where Are Dunlop Tires Made? | eHow.com Where Are Dunlop Tires Made? | eHow.com
​


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## artmart (Sep 21, 2010)

Ah, I had it reversed.... It's an American company with factories oversees. The point being no matter where the company is headquartered their factories could be elsewhere and the DOT code is where to know for sure!

PhilnJill. Thanks for posting the Dunlop story. I think it's drifting back on topic.


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