Rubber Side Down | Buying Your First Mountain Bike

You’ve finally decided to cross the line; you are ditching your lycra-wearing, affogato sipping roadie friends to join the likes of beer-drinking, trail-shredding mountain bikers. I just want you to know, you can never go back. Ok, maybe I’m making it sound a little more polarized than it is… Joking aside, congratulations, you are opening the door to a whole new type of cycling. Mountain biking has a bit of a learning curve in terms of things to look for when picking out your new bike. Let me help make the transition as smooth as possible with a quick breakdown of mountain biking disciplines and key features of bikes.

Local terrain and style of riding will determine the style of bike required. Mountain bikes can be categorized into a few different categories; cross-country, enduro/all mountain and free ride/downhill.

Cross Country (XC)SC4TBCX-1

Cross country riding consists of fire roads and single-tracks that are more geared towards a rider’s endurance and pedaling speed. While still requiring a fair amount of technical handling skills, cross country is more about suffering and pedal power than the other disciplines. XC bikes are weight conscious and have suspension travel between 80 and 120mm. Traditionally, cross-country has been the sole domain of the hard tail, but there are many snappy handling and fast-pedaling full suspension designs available now. More travel provides a more supple ride at faster speeds.

Roadies will feel most at home riding XC—high cadence, clipless pedals, fire roads and rolling single tracks—as it is the most similar to road cycling regarding the necessary skills. XC bikes have geometry closest to that of road bikes.


All-mountain adds a little more airtime to your riding. Bigger drops, rock gardens, and more technical, winding single tracks require a bike with a bit more travel compared to a cross country bike. For all-mountain riding, pedaling efficiency does not carry the premium that it does with XC, although a good AM bike pedals well.

Full suspension bikes are a must for this style of riding, and a full-face mask with a bit of body armor might not be a bad idea.

All-mountain bikes have slacker angles, longer wheelbases, and travel ranging from about 140 to 170 millimeters.


As a beginner mountain biker I wouldn’t recommend you start with the downhill discipline. This is all about carrying as much speed as possible through obstacles that might appear to be more of a cliff than a trail. Downhill bikes have around 200mm of supple travel for big drops and absorbing violent impacts at high speeds. These bikes are typically geared strictly for going fast downhill—seven speeds of low gearing—and don’t offer much in terms of climbing or even motoring on flats. Most downhill riders will also have a XC or AM (All-mountain) bike as well for days when they feel like a rounded workout. You will always be able to identify the DH riders, as they walk their bikes to the top of the hill.

DH bikes have very slack head angles—down to 63 degrees—long wheelbases, and do not handle well at climbing or even singletrack speeds.


Beyond the basic bike, there are a few component decisions that you should consider that probably never came into question on a road bike.

Wheel size is a hot topic in mountain biking these days, with three diameters to choose from; 26,” 27.5″/650b, and 29.” Since you are already used to the 622 ETRTO of 700c wheels, just keep it simple and get a 29″ wheeled bike. 29″ mountain rims and 700c road rims share the exact same diameter. Plus, as much as it hurts to admit, 26″ wheels are on their way to the scrap heap.

Tubeless tires skip the tube; the tire seals to the rim and air is contained inside. These days, a lot of the wheels are listed as tubeless—UST—ready, however you should double check to make sure. Tubeless setups have the advantage of being able to run at lower pressures without the risk of pinch flatting. Lower pressures also provide better grip on the trail and increased shock absorption. At lower pressure, tires deform more easily over rough terrain, effectively grabbing on to rocks and other obstacles for traction.

Although disc brakes are still a controversial topic in the road industry, they are a must in the mountain segment. Don’t think twice about mountain discs, and make sure they are hydraulic. Braking performance is a must when navigating tight trails at high speeds.

Compared to road bikes, drivetrain options are more plentiful in the mountain bike world. While most road bikes come with doubles and 11 speeds, mountain people get to choose from 1x, 2x, and occasionally 3x setups with either 10 or 11 rear cogs. Triples offer a lot of low end gearing options, but with a lot of gear ratio overlap and added weight. Unless you really feel the need, most will be able to get away with a double. They are a lot easier to keep in tune and offer similar gearing options. 1x systems have a steeper price tag, but offer significant weight savings and also the simplicity of ditching that front derailleur. SRAM is currently dominating the 1x market with their 11-speed setups, offering a 42T rear cog for climbing and a variety of front rings to suit your needs. Shimano is joining the 1x rat race with an XTR variety that offers 40T rear cogs paired with new derailleur designs that help with the larger gearing and lack of front shifting. If you have the money, I would suggest the simplicity and future proof nature of the 1x, but smooth shifting 2x and 3x groups will work wonders as well.


Dropper posts are a must for any serious all mountain riding

What’s a dropper post you ask? These seat posts allow you to make quick, on-the-fly height adjustments to your seat post when descending technical terrain. Dropping seat height is desirable so body weight can be shifted rearward to maintain stability, traction and balance. Cross country riders can probably get away without a dropper post, but most all mountain riders will want one. Without it, you might find yourself stopping and manually adjusting your seat at the top of the trail, or wishing you did halfway into a tricky descent. Bike manufacturers tend to equip their newest two-wheeled trail shredders with dropper posts, so just check the specs on your prospective model.

Roadies will feel right at home with clipless pedals on their new mountain bikes. Mountain clipless pedals offer two-sided entry and tend to be a bit more robust than their road counterparts, offering a bit more durability in case you slam one against a rock. Cross country riders tend to ride clipless, but as you branch into the all mountain and downhill disciplines you will see people riding more and more with flat pedals. Flat pedals and stiff platform shoes provide good power transfer while also allowing riders to put a foot down in a corner or pull a steezy double backflip in their homemade dirt park. Take a second to consider your options before taking the plunge on a new mountain pedal.

Equipped with all your new mountain biking knowledge, I’m sure you can make an informed decision about your new mountain purchase. It is easy to buy a bike tailored for a specific purpose, only to outgrow the bike quickly and need something with more travel or rear suspension later on. I encourage you to think a bit about where you see yourself riding in the future and maybe purchasing a bike you can grow into as you develop trail skills and become more comfortable in the dirt. Check out the Art’s Cyclery Blog for many more articles about mountain biking gear and skills. Feel free to comment with any questions you have. Happy trails!

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Rubber Side Down is a weekly column dedicated to the fledgling cyclist in all of us. Art’s Cyclery Web Content Editor, Brett Murphy is not a professional cyclist, and doesn’t try to masquerade as one either, but he does love to ride bikes. Whether you are clipping in for the first time or counting down the days until your first race, read on, learn from his mistakes, and keep the rubber side down.