I've never really had to mess with my stem much, but I need to get a new one and I have a question: The specs for my bike say the stem's clamp diameter is 26.00 mm. But when I look online, all the stems I see say their clamp diameter is 31.8mm. I saw one at 26, but it was pretty cheap looking. Will 31.8 work, would I need a shim or something, or do I need to find a 26?