I snapped my seatpost clamp and I'm hoping someone can help me figure out the correct size. My bike is a GT Karakoram, but I don't know exactly what year it is; maybe early to late 90s. It's black and purple has the groove tube for the cables. The seatpost is 26.4mm. The Clamp has the last number scratched off. It says 30._. I need help with that last number. I THINK it's 30.8, but there aren't a lot of options out there for that size. From what I can see (a little of the top part of the scratched off number), it's one of these possiblities: 30.0, 30.2, 30.3, 30.6, 30.8, or 30.9. Any help would be much appreciated.