Most RV tires are in need of replacement between 5 and 7 years of age. DO NOT push the 7 year mark! A failure of a tire can cause extreme damage to the body of the coach, especially if it's a rear tire. They may not look bad but ultra violet rays have taken its toll.
The cost of RV tires is high, but your life depends on those tires. Exposure to UV rays degrades the rubber and as Jim says, tires begin degrading the minute after they are manufactured.
Check the manufacture date of your tires. For information on how to read the tire manufacture date, see below:
From the Glossary Of Terms, compiled by RV Forum staff member Don Jordan:
Generally accepted rules of thumb in the RV world are that regardless of low mileage or low tread wear, tires should be replaced every 5 to 7 years maximum. Exposure to sunlight, ozone, and ultra-violet radiation causes gradual loss of the plasticizers that keep the tires flexible. Sidewall cracking can often be seen but may not always be apparent. So, for safety?s sake and to avoid sudden catastrophic failure replacement should be done on an age priority basis. This does not mean that obvious tread wear, sidewall damage, or any other physical problem with the tires should be ignored if they still have ?x? years to go before they are ?too old?.
The National Highway Traffic Safety Administration (NHTSA) ?Tire Identification and Record Keeping Regulation?, revised July 2, 2000, specifies a new 4-digit date code that must appear on all tires sold in the United States. The complete DOT (Department of Transportation) code is in the following format: DOT MMM SS TTT DDDD where MMM is a 3 digit manufacturer ID; SS is a tire size 2 digit code; TTT is an optional tire type code; and DDDD is the date of manufacture code where the first 2 digits indicate the week of manufacture and the second two digits are the year, i.e.: 2802 would indicate that the tire was manufactured the 28th week of 2002.
Note: tires manufactured before July 2, 2000 had a 3 digit date code where the first 2 digits are the week of manufacture and the last digit is the year. Tires manufactured in the 1990?s had a triangle following the 3 digit code while tires manufactured in the 1980?s did not, i.e.: 282 with a triangle would indicate that the tire was manufactured the 28th week of 1992 while if there is not a triangle following the 3 digits it was manufactured in the 28th week of 1982. The newer 4-digit code eliminates any ambiguity in the year of manufacture and allows continuation of the system through the 21st century.
It is strongly recommended that when buying new tires you insist on all tires having the same date of manufacture and that that date should not be more than a few months prior to the date of purchase. Otherwise you will be buying tires that will need to be replaced sooner than necessary.
Go beyond the 5 to 7 years since the tire date of manufacture (note not date installed) and you are exposing yourself to spending bigger buck than you would for tires. For more valuable information on tire and tire care see the video at:
http://www.michelinrvtires.com/michelinrvtires/other/RvVideos.jsp . The video is put out by Michelin but applies to all tires.