My Cart


Shipping & taxes calculated at checkout

TPC Blog

Back To Blog

Buyer's Guide: Pre-Owned Mountain Bikes

By Bruce Lin

Buying a new bike is exciting, especially when you have the world’s biggest selection of pre-owned bikes at your fingertips. As you start researching and making decisions, all the different options and terminology involved with choosing a modern mountain bike can be overwhelming. If you’re looking to take the plunge and try a Certified Pre-Owned mountain bike, or any new mountain bike, these are the basics you need to know to get started.

There are lots of different paths you can follow on your mountain biking journey, and it can take time and experimentation to learn what you really need or want. The best part about buying used, especially with Certified Pre-Owned (CPO) bikes is that it’s easier and more affordable than ever to get on a high quality used bike. Perks like Guaranteed Buyback make it easy to trade-in your CPO bike for your next bike when you're ready for something new. If you have any questions, our Ride Guides are always here to help you on your journey.

See our Mountain Bike Collection if you want to browse the biggest selection of quality used bikes available.


Mountain bikers getting rad on a trail

Is this how you imagine your riding? Or does it look a little different?

Rider type 

  • What type of rider are you?
  • How will you use your bike?

To define your riding style and help narrow down your bike choices, imagine your dream riding scenario. This level of fantasy exists in some form within all of us, even if you've never ridden a bike before.

Do you see yourself ripping down trails at high speed, roosting corners, and boosting off jumps? Do you imagine yourself pedaling a featherweight bike easily uphill, going long distances, and summiting high mountains? Do you want a bike that improves the experience of descending or climbing?  

Understanding how you idealize riding will ultimately be the compass that will point you toward the right bike. The more downhill focused you are, the more "enduro" your bike should be. The more bike weight and pedaling efficiency matter to you, the more "XC" your bike should be.  

Your dream ride is something that might change or evolve over time. Saving money and buying Pre-Owned and Certified Pre-Owned bikes lets you continue to explore, experiment, and develop yourself as a rider. With helpful options like Guaranteed Buyback, it's easy to change course and try something new. 

Bike type

Full suspension

Full-suspension bikes use a shock and linkage to provide additional suspension in the rear. The main advantage of a full-suspension bike is that the rear suspension helps absorb impacts, gives riders a larger margin of error when going down a trail at high speed, and improves comfort on rough terrain. You can be less picky about line choice and don’t need to work as hard to remain smooth as you do on a hardtail. There are a wide range of travel options to choose from, depending on the style of riding you typically prefer. 

Suspension is a big concern for used mountain bikes. The fork and shock take a fair amount of abuse, and will generally require servicing to maintain good performance and feel. When looking at used mountain bikes, it’s a good idea to have money budgeted in case a bike needs a fork or shock service after the purchase. Fortunately, Certified Pre-Owned bikes have all suspension components inspected and serviced by our mechanics, so they’re always ready to perform right out of the box.

Choose a full suspension bike if you ride on rougher trails or need an advantage when descending. Full suspension bikes weight slightly more than comparable hardtails, but are still relatively efficient and can give you added comfort on more technical courses. 

If you need help discerning a bike's category or which bike is for you, you can always contact our expert Ride Guides for assistance. 

XC: 100-110mm rear travel (~4")

XC (a.k.a. cross country) mountain bikes are designed to be faster, and more efficient for climbing, sprinting, and covering ground quickly. XC bikes are often lighter, easier to pedal, and have quick and responsive handling. They are good for riders focused on fitness, speed, and climbing, endurance and long distance rides, and XC racing.

Popular models: Specialized Epic, Trek Top Fuel, Orbea Oiz

Shop XC bikes

Trail: 110-150mm rear travel (~5")

Trail mountain bikes are all-rounders, splitting the difference between XC and Enduro. In general, these bikes sit in the middle in terms of aggressiveness, travel, weight, and geometry. They are decent for a wide range of riding uphill and down, and are usually the best choice for the majority of riders looking to have fun and ride a large variety of trails.

Popular models: Yeti SB5, Santa Cruz Hightower, Specialized Stumpjumper

Shop trail bikes

Enduro: 150mm+ rear travel (~6")

Enduro mountain bikes are all about going downhill fast. Most enduro bikes will have more suspension travel, aggressive geometry geared more toward downhill stability than fast climbing, and heavier, more rugged componentry. They are good for riding steep and technical terrain, bike parks, and enduro racing.

Popular models: Santa Cruz Nomad, Specialized Enduro, Orbea Rallon

Shop enduro bikes


Hardtails have a suspension fork at the front of the bike with a rigid rear end. Because a hardtail doesn’t have a rear shock or the moving linkages required for rear suspension, it’s often cheaper and easier to maintain. Hardtails are very efficient when pedaling because there’s no rear suspension to bob or squat under power. Hardtails are a popular option for XC riders looking for the lightest and most efficient bike possible. XC and trail hardtails are the most common, but enduro hardtails do exist for those looking for a unique riding experience. 

On rough and technical trails, they require more care when it comes to technique and line choice because the rear end is less forgiving of mistakes and big hits. Choose a hardtail if you’re looking for a bike that’s simpler and more reliable, or easier and cheaper to maintain, if you want an ultra-light XC racer, or if you want a bike that requires sharper riding technique and attention to improve your riding skills or make mellow trails more exciting. A hardtail can also be equipped with a rigid front fork instead of a suspension fork.  A full rigid mountain bike can be a rough ride, but because there’s no suspension to sag or bob, rigid bikes are incredibly efficient and light. They are good for smooth trails or those willing to suffer. No moving suspension parts also mean they are cheaper to maintain.

Popular models: Niner Air 9 RDO, Scott Scale, Trek Stache

Shop hardtails

Wheel size

In the beginning, 26” wheels were the standard for mountain bikes. Over the years though, new and different wheel sizes have taken over. The used mountain bike market is now filled with a plethora of size options, each with different characteristics, advantages, and disadvantages. Riders can select and experiment with wheels and tires that work best for them and their riding.

Classic 26” wheels have mostly fallen by the wayside, but that means you’re often able to find used 26” bikes for a great price as long as you’re okay with compatibility concerns and reduced availability of new parts. Otherwise, it’s best to look for a used mountain bike utilizing one of the below options.

*Note: The majority of mountain bike wheels are now tubeless-ready. Non-tubeless options are becoming increasingly rare, even in the used marketplace. Any modern mountain bike should be tubeless at this point. Contact our ride guides if you need help with your tubeless setup! 


27.5” is the smallest common wheel size on modern bikes. 27.5” has replaced traditional 26” wheels as the defacto wheel size for the majority of enduro and downhill style bikes. It is good for those who want a playful bike that is easy to throw around, who ride more jumps and steep, technical tracks, or shorter riders who find 29” wheels to be too cumbersome.

Shop 27.5”/27.5+ bikes


27.5+ refers to wheels designed to run 27.5” tires between 2.8-3.0” wide. This larger tire provides more grip and a smoother ride thanks to greater air volume. Some bike models can switch between the 27.5+ and 29” wheel because they are a similar diameter. This is a good tire size for those looking for increased confidence and grip in loose conditions, or more comfort on longer rides.

Shop 27.5”/27.5+ bikes


29ers have greater “rollover” thanks to their larger diameter, making it easier for a bike to carry speed and momentum through rough terrain. They are the most popular option on modern XC bikes. It’s starting to become popular in enduro and downhill. It’s a good wheel size for XC racers, trail or enduro riders more interested in straight-line speed than maneuverability, or taller riders.    

Shop 29”/29+ bikes  


29+ refers to wheels designed to run 29” tires between 2.8-3.0” wide. This larger tire provides more grip and a smoother ride thanks to greater air volume. 29+ is the largest mountain bike diameter and has the most rollover of any wheel size at the expense of more weight. 29+ is popular for applications like bikepacking and is good for riders seeking greater comfort and traction. Smaller riders, however, may find them to be too large.

Shop 29”/29+ bikes  


To be considered a fat bike, wheels are 26” (sometimes 27.5”) and tires are generally between 3.8-5.0” wide. This ultra-wide rubber allows fat bikes to ride with some amount of “float,” meaning the tire doesn’t sink into the trail surface. This makes fat bikes the ideal choice for riding in unique conditions like snow and deep sand. The wider the tire, the more float it will have.

Shop Fat Bikes

Frame material

Choosing the frame material for your bike is often going to come down to preference, price, and the type of riding you’re interested in. The integrity of a bike’s frame is paramount to its value and safety so it is essential to catch structural damage, cracks, and other potential issues. Carbon often receives the most scrutiny, but all types of frames can fail and should be carefully inspected when purchasing a used mountain bike.

If you choose a Pre-Owned or Certified Pre-Owned bike from The Pro’s Closet, they are all professionally inspected and by one of our full-time bike mechanics and guaranteed to be in perfect working order. They are also professionally packed and shipped so they arrive safely.   


Aluminum is often the most affordable material. When comparing two similar bikes it will usually be heavier than carbon, but it’s also less expensive and considered to be slightly more durable. This makes it a good option for budget-minded riders and enduro and downhill focused riders who expect to crash their bikes. 

Shop aluminum bikes

For more information, check out our detailed Carbon vs Aluminum article. 


Carbon is the latest and greatest material used in mountain biking, and most high-end bikes will use it in some form. It can be used to make frames that are lightweight, stiff, and responsive. This generally comes at a price as carbon frames are often more expensive. See our more in-depth article on the pros and cons of carbon vs aluminum here.

Shop Carbon bikes

For more information, read out our Carbon Fiber 101 article


Steel is the classic frame material, used since the bicycle’s inception. It’s revered by many for its supple ride quality and durability. A well-cared-for steel frame will likely last a lifetime. It is slightly heavier than other materials, but plenty of riders prefer it simply for the feel. It’s most often used for hardtail bikes.

Shop steel bikes


Like steel, titanium is a classic frame building material most commonly used for hardtails. It has a similar supple ride quality to steel, but is much lighter, and has increased durability thanks to its higher strength and resistance to oxidation. The trade-off, though, is a much higher price tag. Few big brands offer a titanium frame, so it is often limited to smaller boutique and custom builders.

Shop titanium bikes


When buying a used bike, it’s important to check the function of the drivetrain and make sure it has been properly cared for. How clean a drivetrain looks speaks volumes, and simply shifting through gears and pedaling around can tell you a lot about how well a bike’s drivetrain is working.

Check the teeth of chainrings and cogs for wear, and chains for excessive stretch in case they need to be replaced. Every Pre-Owned bike at The Pro’s Closet has been professionally serviced by our mechanics, so the drivetrain is always fresh and tuned right out of the box.

Used bikes may often have drivetrain components from older component generations. But any drivetrain that's been properly cared for, serviced, and tuned, will work just as well as new equipment. 

The two most common drivetrain manufacturers are Shimano and SRAM. Which brand you choose will largely come down to personal preference. Entry-level drivetrains will generally be cheaper, but less refined feeling and heavier. As you become more experienced and pickier, higher-end components may become more appealing. 

Basic component hierarchy










Deore XT





1x vs. 2x
Drivetrains with a single front chainring are known as 1x (pronounced “one by”). 1x drivetrains are the most popular option for modern mountain bikes because of their increased simplicity and reliability. The downside is generally reduced gear range, but 12-speed 1x drivetrains have largely eliminated this.

1x drivetrains utilize a chainring with a “narrow-wide” tooth profile which helps prevent the chain from falling off the chainring in rough and bouncy terrain as well as a clutched rear derailleur which helps chain retention by maintaining constant tension on the chain.

Shimano is currently the only manufacturer still offering a traditional 2x (“two by”) drivetrain. 2x drivetrains offer greater gear range, which is beneficial if you need an easier low gear for climbing or a harder high gear for pedaling on downhills and flat sections.

10/11/12 speed

With each generation, drivetrain manufacturers have been able to add cogs on the cassette to increase drivetrain speeds. The newest drivetrains have 12 speeds. The advantage of more speeds is that they allow for a wider gear range. Older 10 and 11-speed drivetrains work great, and will cost less, at the expense of the large gear range.


Single Speeding is a unique niche within the mountain bike world. It means riding with one gear, i.e. no derailleurs and no shifters. People who love singlespeeding love simplicity. Generally, singlespeeding requires a good amount of fitness. This is because you can’t shift to an easier gear when the trail gets steeper. 

Singlespeeds are generally hardtails designed with moveable or sliding dropouts to tension the chain. Because single speeds lack most of the normal moving components of a multi-speed drivetrain, they are easier to maintain, reliable, and much cheaper. This makes singlespeeding a good option if you’re on a budget and willing to suffer on some climbs.

Dropper Posts

One of the greatest recent innovations to benefit mountain bike riders is the dropper post. A dropper is a hydraulic or spring-actuated seatpost that is height adjustable. These posts are usually controlled by a remote at the handlebar which allows a rider to instantaneously lower their saddle.

For optimal pedaling, you need proper leg extension to generate power and be efficient. A saddle positioned for optimal pedaling, however, is generally too high for most riders to descend comfortably. A lowered saddle is out of the way, allowing you to easily maneuver the bike around beneath you when cornering or descending on steep and technical terrain.  

Like suspension, dropper posts on mountain bikes take a lot of abuse. Used droppers and even some new ones often have a poor reputation for reliability. If any sag, stiction, leakage, or other issues are present, then a dropper will need to be serviced or replaced. It's often expected and not a dealbreaker when buy a used mountain bike, as long as you have the money budgeted. Like suspension, The Pro's Closet inspects and services dropper posts on all Pre-Owned and Certified Pre-Owned mountain bikes, so there's just one less thing to worry about. 

Some riders may find that they don’t need a dropper post. Either their local trails aren’t technical enough to justify its use, or they are concerned about the weight a dropper adds over a conventional seatpost. This is the reason many XC riders and bikes don’t use a dropper. It’s ultimately up to each rider to decide if a dropper is necessary or not, but it is a feature that is worth considering when looking at a new bike. A dropper can be added or removed in the future.

Shop dropper posts

See our Mountain Bike Collection.


  • Excellent breakdown of each bike component thank you for providing the answers to the questions I had when purchasing a new mountain bike.

    al loffredo on

  • Great article providing all the information needed to make an informed bike purchase, in a plain and easy to comprehend format. Thank you!

    cheryl knight on

  • Thank you for this excellent article! As an absolute beginner trying to land on a first bike, this was the exact type of explanation I needed for the different choices.

    Miriam Eirin Hiorth Johnson on

  • Excellent information. Thanks.

    RJ Linter on

  • Nice work here! More people should be asking for good solid and honest input like this!

    Jim Soldera on

  • Information was clear and easy to understand ! Any person purchasing a mountain bike was given an excellent overview of Wheel size, Frames, and drivetrains! Thanks!!!

    WIllie F JOHNSON on

Leave a comment

Please note, comments must be approved before they are published

Newsletter Sign Up