1974 Argosy 27 foot - Tire question

[Lsbuckeye]

Hello!
I'm new here. Looking to help my son with information on getting new tires for his newly acquired '75 Argosy 27 foot Airstream. How do we know the size to get?

[CapriRacer]

First, see if you can find the vehicle tire placard. It should list the original tire size and the specified pressure for that size. The vehicle tire placard may be on the tongue or on a door, or doorframe, or in a cabinet.

No doubt, the original tire size is no longer available - the tire industry now uses a different system - but we need to know what was originally specified so we have an idea of how big your fenderwells are and how much load carrying capacity is needed.

If you can't find the placard, what tire size is on there now? Please include all the letters and numbers, and especially the load range or ply rating (PR)

Lastly, you should weigh the trailer. It is not a given that the manufacturer accurately assessed how much stuff people put in their trailers.

[Lsbuckeye]

Hey thanks! Amazingly the tires were in GREAT shape and the trip to home was uneventful! We are so grateful!

[mccrosti]

If the tires are over five years old replace them - regardless of what they look like.

[nrgtrakr]

There is a lot of info available about tires. My 75 had 7.00x15 light truck tires on it. The oldest of which by the DOT numbers could be original or from 1985 no way to tell for sure, the newest was from 1999; all with good tread, no cracking and holding air. The 7.00x15s were 27.88" in diameter. Due to signs of tire damage on the lead edge of my wheel wells, I replaced the antique/vintage tires with 205/75-15 trailer tires which are 27.1" in diameter. 225/75-15s are 28.1" The original tires were load range C, so the new ones were also; load range C rated at 1,820 pounds each, so 7,280 pounds total and the GVWR of the trailer is 7,000 pounds.

The general guidance from the tire industry is tire lifespan is anywhere from 3-10 years depending on the source you read and even more dependent on whether the tire is under load and subjected to UV light. Tire warranties are typically 4 years from purchace.

[natedogg7]

Originally Posted by nrgtrakr

There is a lot of info available about tires. My 75 had 7.00x15 light truck tires on it. The oldest of which by the DOT numbers could be original or from 1985 no way to tell for sure, the newest was from 1999; all with good tread, no cracking and holding air. The 7.00x15s were 27.88" in diameter. Due to signs of tire damage on the lead edge of my wheel wells, I replaced the antique/vintage tires with 205/75-15 trailer tires which are 27.1" in diameter. 225/75-15s are 28.1" The original tires were load range C, so the new ones were also; load range C rated at 1,820 pounds each, so 7,280 pounds total and the GVWR of the trailer is 7,000 pounds.

The general guidance from the tire industry is tire lifespan is anywhere from 3-10 years depending on the source you read and even more dependent on whether the tire is under load and subjected to UV light. Tire warranties are typically 4 years from purchace.

I just measured and I dont see how an extra inch fits in that wheel well of my 74 argosy. assuming 205 75 15 dimensions.

[natedogg7]

Did you use the original rim's?

[CapriRacer]

Originally Posted by nrgtrakr

..... The 7.00x15s were 27.88" in diameter. ….

I don't think that is right.

According to my Tire and Rim Association yearbook, a 7.00-15LT is supposed to 29.6" in diameter - making it 1.3" larger in diameter than an ST225/75R15 (28.3").

Side note: TRA dimensions are the "design" dimensions, not necessarily what the tire is actually built to.