That's false. There's only one "US size" and the numerical value just don't change - size 10US is size 10US. i.e. If you truely wear 10.5 size, the snowboard boots should be 10.5. The problem is that, majority of people don't wear the proper size tennis shoe they tend to wear it larger. If you're a runner, you know that getting fitted shoe is very critical.
Tennis shoe, there's a high QC in getting the size produced correctly. However, the complexity of making snowboard boots required complex QC to produce correct size measurement.
The rule of thumb is, if you "truely" wear a size in tennis shoe, that's your snowboard boots! This shoe size problem has plagued the whole snowboard boots industry!
Originally Posted by zk0ot
genrally you should never wear boots the same size as your shoes... most always smaller never larger.