i used a really good tire glue and professional patches from napa to repair a side wall of an old 35" mtr.
had to heat the glue up a bit but it held for a long time and mainly wheeling trips aired down to 8psi.
i asked americas tire one time when i was there if i did it right and they said they normally wouldnt patch a sidewall gash but thats how they do it on the tread of tires when they get a nail or small cut, they use patches or they recommend getting it vulcanized.
