(You’re looking at big cracks if you’re not sure)
Humidity and temperature will do this. I have the same problem on the rear tyre of my cargo bike, which stays covered but outside.
Some compounds are more prone to this than others.
@Bezzin started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
(You’re looking at big cracks if you’re not sure)