I have a 17C clincher (BDOP diy kit) with a 25mm (Conti GP4000). In 2015, I built the wheels but couldn't use them because the tire was rubbing against the rear fork (upper - where the breaks are screwed in). At the beginning of this season, I tried them again and this time there was no issue. I was quite puzzled and wondered if the tires aged and caused it to shrink in size. I was using the tire on a second bike I do not have anymore. The fork had more clearance on it so I had the opportunity to put some kms on the tires.

However, this last week end was quite hot in quebec and now the tire rubs against the fork again... and it is clearly bigger than what it was at first. I use the same pressure - between 80 and 90.
I am very surprised that temperature can induce such a big difference. I can't use my nearly brand new set of wheel due to that
I guess my only option left is to sell the bike and get a new one with more clearance.