Tires: China RV Tire 8R19.5, low profile tires, 4 digits

Question
Had two blow outs on one trip.  Found tire without DOT knowledge, and it was made in china and had it put on inside rear.

Got home, and bought two michlens but the home tire company said tires were 5 years old right out of the warehouse so he got me two from another dealer made this year.

The china tire on inside rear has dot code of c71680428.  The tire has 85 pounds in it, same as the one right beside it but....the tire side wall looks like it is low on air or it is a low profile tire.

What is the year it was built from the dot code?
Are china tires low profile tires or do they require more air.

Answer
Ron,

I don't think you captured the DOT Code.

DOT codes are a 10 to 12 digit number located near the letters "DOT".  BTW the digits can be numbers or letters.

The first 2 digits are a code for the manufacturing plant.  

The next 2 digits are a code for the tire size.  

The next 3 or 4 digits are a code for the type of tire.  

The last 3 or 4 digits are the date code.  The format is week/week/year/year or week/week/year.  

Starting in the year 2000, the date coding used is 4 digits.  That means the highest number you should see for the year is 08.  Before 1999 the format was 3 digits.  1999 and 2000 are transition years, so you will find both 3 and 4 digits.


1)  Yours is a 9 digit code.

2)  The first 2 digits - C7 - map to a US tire maker - Ironsides - which I've never heard of,  but I am working off an old list and the number might nit be assigned to someone else.

But the important thing:

Duals should be the same size , make, and model, and about the same state of wear.  This is standard procedure and it's not clear that is the situation.  If anything, it sounds like the tire from China has been matched up with a Michelin.  

It's also unclear if you have 4 Michelins or 2.  Nevertheless, you need to arrange it so that your dualed tires match.  That will take take of the difference in deflection.


And - No - the pressure needed is the pressure needed, but the tires may react differently to pressure and that's why dualed tires should match.