well this might be of interest to some of you. Ever wonder re that brand new spare tire in the trunk (boot?) and replacing it with a worn one and fianlly getting some use out of the new one? Wonder no more. I did just that and what I observed was the following. There was no problems whatever re sidewalls cracking, delamination, etc.... worked just fine. the only caveat was that the tire wore out in the space of less than a year. the rubber is old and brittle and just abrades very quickly. In short, not worth doing. Now I've got 3 good tires and one useless one..... sooo, have to buy a forth new tire nonetheless.
cheers, guenter