I ran Jacos and TRC all of last season in stock and 19T and had never had to glue sidewalls ever (I don't like doing it—I think it looks hack and it makes the tires behave erratically). I was surprised that after a single test session in stock (purple/grey), that the rears pulled themselves apart. After a re-glue, they were fine, but I wouldn't run those again without gluing them.