I put a set of ProComp MTs on my 79 in about 2005. Drove it for a couple years and parked it until 2016, out in the back pasture in the sun. All 4 were still up and holding air after 10 years sitting. I fired it up and drove it to work for about 3 months until I could afford a set of new Coopers. Figure they were dry rotted pretty good when you could twist lugs off on pavement when getting on it.
