Not all mountain bikes are created equal. There are a wide variety of bikes intended for different styles of riding and the type of terrain being ridden on. Below I will go through each type of bike and explain what its intended use is. Keep in mind that mountain bikes, in general, are becoming more and more capable. An XC bike or Trail bike 10 years ago would not be able to do what modern versions of those bikes can do today. This is all because trails have gotten more flowy and technical over the years and the bikes have evolved to accommodate more modern trails. This doesn’t mean they are not good on classic-style singletrack or even gravel roads and double track, in fact, bikes have gotten better overall and continue to do so.
I will start from the most basic hardtails and then go to full suspension from the least amount of suspension to the most amount.
Fully Rigid and Hardtails
Bikes with no suspension or only suspension on the front of the bike. These bikes will come in a variety of materials such as chromoly steel, aluminum, titanium, or carbon.
XC: These are the typical and more traditional mountain bikes that have been around for a long time. They have gotten a lot better in recent years, especially when it comes to geometry and how a mountain bike is sized to fit a rider. They generally have a front suspension fork on them, but not always. Sometimes bikes will still come with a rigid fork. It’s not very common, but they are out there. These bikes are designed to be ridden on XC-style singletrack and racecourses. Expect the front end to be a little lower and your body to be more in a leaned forward and more aerodynamic position on most XC bikes. They will generally have 10 – 12 speed rear cassettes and most bikes have gone to just 1 gear up front, although some bikes still have 2 gears in the front.
Singlespeed: These are still around and became very popular in the late 90s and early 2000s. The trend has died off some, but many companies still offer some singlespeed models and they are usually fully rigid bikes without front suspension. The idea is to have a pure simple riding experience without all the complexities of modern geared and full suspension bikes.
Dirt Jumper: These are almost always singlespeeds, but the frame is super low, as is the seat height. They will often only have a rear brake and most come with a suspension with less travel, like 80mm – 100mm. They are great for dirt jumping, pump tracks, skateparks, and even some bike parks. Going on longer singletrack rides is possible, but the rider would not be very comfortable on a longer ride due to the harder gearing and low seat height.
Trail/Enduro: This is a newer style hardtail bike. They are much like their full-suspension cousins, long and slack! With short chainstays, long front ends, slack headtube angles, and longer travel suspension forks up front, they are designed for rough fast terrain. Many riders are realizing you don’t need big rear suspension travel to get gnar on the trails.
Drop Bar: These bikes might also fit into the gravel bike category and are not really considered mountain bikes. But there are enough drop bar gravel bikes that are longer, slacker, have short stems, and have the ability to run larger volume tires that they are plenty capable of some singletrack fun.
Bikes with suspension in the front and rear of the bike. Aluminum and Carbon are the dominant materials for full suspension bikes. There are however a small number of manufacturers that make chromoly steel full suspension bikes and even a smaller number that makes titanium full suspension bikes. The cost of good quality full suspension bikes is usually a pretty significant jump up from a comparably specced hardtail bike.
XC or Crosscountry: 100mm – 120mm of suspension travel. These bikes are made for speed and pedaling efficiency. They climb faster and take a lot of the harshness out of the trail. The suspension in the rear will be designed for maximum efficiency to reduce any loss of power while pedaling. Being lighter weight is also extremely important. These are common for XC racers to use and people who are doing long-distance rides.
Downcountry: 120mm – 130mm of suspension travel. This is a relatively new category. These bikes are oftentimes just beefed-up versions of XC bikes. The idea is to still focus on the bikes being lighter weight and good at climbing, but they are made to be a little more capable on the descents than a traditional XC bike.
All-Mountain or Trail: 130mm – 150mm of suspension travel. I put these two together because they are so close to the same now I am surprised I still see the term All-Mountain used anymore. These bikes have become a lot more capable of descending over the last few years. This category is becoming very popular because the geometry has gotten a lot more aggressive all while maintaining a relatively lightweight bike. For most riders, if you are not racing XC, this is the bike they should be getting. They are pretty much a do it all tool that can handle some pretty gnarly descents and terrain all while still being pretty efficient for climbing and regular singletrack riding.
Enduro: 150mm – 180mm of suspension travel. This is also an extremely popular category of bike. Enduro bikes are pretty capable of climbing, but getting up the hill fast is not their main goal. The goal is to get to the top so you can shred the downhills. That is exactly what Enduro Racing is. It’s a series of downhill trail sections where the rider must climb to the top for their next run. The climbing isn’t timed, but the downhill sections are. So these bikes will be extremely capable on the downhills and they will be built a little heavier to handle the big hits.
Freeride or Park: 170mm – 180mm of suspension travel. This category has been around a long time. They are basically single fork crown downhill bikes. These bikes are basically made to ride lift access trails. They can climb if needed, but their main goal is to hit the big downhill stuff and massive bike park style jumps. The geometry is also very similar to that of a downhill specific bike.
Downhill: 200mm or more of suspension travel. It’s easy to identify a downhill bike because it has a dual crown fork on it, is super long, and has a super slack headtube angle. They will generally only have 7 – 9 gears, unlike the more common 12 speeds we see on all the other bikes. These bikes are not designed for climbing, their main goal is to go downhill over gnarly terrain as fast as possible. They weigh a lot more than any other category because being strong is the goal.
Slopestyle: 100mm – 120mm of suspension travel. These bikes are not very common anymore although slopestyle is still a popular event. These bikes are essentially full suspension dirt jump bikes and are designed for big jumps and big tricks. Many slopestyle riders will ride DJ hardtails and that is likely why you don’t see many of these available anymore.