As the title would suggest I was wondering what the difference was between the SRAM PC-89 and PC-99 hollowpin chains were. One is supposedly a road chain and one an MTB chain according the the SRAM site but I can't see any reason why a PC-89 couldn't be used on a mountain bike and and a PC-99 on a road bike. Are the plates different? Is there any variation in materails used? Would anyone care to enlighten me on this? Thanks in advance.