"700C" is not, nor has it anything to do with, 70cm - cm inferring centimeters. So none of it truly makes sense. I just had an utterly bewildered guy here to deal with a wheel-problem. I had to explain all this to him. I asked him if he was still confused. He said he was. I told him I was glad he was as only a certifiable lunatic could make sense out of this system. He agreed.