For professional as well as recreational riders, a lot of thought goes into choosing a Mountain Bike. When it comes to picking out a Mountain Bike Helmet, the process of selection is quite similar. The type of helmet you decide to get, depends on several factors such as, personal preference, size of the head, design, and riding style. Before we start the review of the best mountain bike helmet under 100, here are a few things you need to look out for before buying a mountain bike helmet.