I have and old "road" size bar which measures exactly 26mm, and its mating stem (both halfs (handlebar end)) fit perectly to a pair of handlebars which are 25.4mm, are these compatiable? As different companies make different size handlebars 25.4, 25.8, 26. Do different stem manufactuers make different size bar clamping diameters? what is compatiable. Thanks