My Full Suspension Specialized MTB is a great bike, but I’m thinking about a new ride. So I began to wonder, what if I build my next mountain bike myself?
Can I build a mountain bike myself?
Yes, you can build a mountain bike yourself. Now, unless you are a mechanical engineer and metals expert, don’t try to craft the frame and components on your own. Instead, pick and choose every component, all the way down to the bar grip and seat post clamp. Then put all the parts together.
Mountain Bike Build Checklist Summary
Here are all the parts you’ll need to consider. Later we’ll discuss each category in more detail.
- Frame – Hardtail, dual suspension or fat bike. Frame material can be aluminum, steel, carbon or even a combination. Choose wheel size (current industry standard is 29”). Also, brake systems might not work on all frames.
- Rear derailleur hanger – Connects derailleur to frame. Usually aluminum.
- Wheel set – Pre-built wheels. Look for something light but not flimsy. Exotic wheels might require special tools.
- Hubs, spokes, rims – For those who want to build out everything. Wheel building is not for beginners. Hub material, performance and stiffness matter.
- Wheel axle – Thru axles are now standard. Quick release is an older option.
- Headset – The set of bearings that allow your fork to rotate. Most are threadless.
- Front Fork – In most cases, you’ll want a suspension fork. Many, many models to choose from.
- Rear shock – For dual suspension bikes. Might be included with frame.
- Stem – Attaches headset to handle bar. Length and angle are important.
- Handlebar – Consider width, sweep, rise, overall geometry and material.
- Shifters & brake levers – Can be purchased separately or in group sets.
- Handlebar grips – Highly personal.
- Brakes and brake pads – Discs rule. Cantilever and V-brakes are other options.
- Seatpost – Standard or dropper post. Consider different materials (i.e. aluminum vs. carbon fiber).
- Seat post clamp – Must work well. A place for weight weenies to shave off a few grams.
- Seat – Highly personal. Must fit to be comfy. Not too clunky though.
- Chainrings – The cogs at the front. Typically a set of 1,2 or 3, and they can be part of groupset.
- Crank arms – May also be part of grouset, but you might swap out. Length and weight are key considerations.
- Bottom bracket – Where the cranks attach. Look for something solid here that is compatible with your frame.
- Cassette – Cluster of cogs at the rear. Also, usually bought with groupset.
- Chain – Shimano and SRAM are the leading brands. Come with groupset.
- Front and rear derailleur – Focus on performance. Also, part of shifting groupset.
- Pedals – Flat or clipless. Typical riding terrain will help decide.
- Cables and housings – For non-hydraulic brakes and shifters.
- Tires – Lots of choices out there. Riding style and terrain will determine the tread type.
Wow! That’s a long list.
Yep. The list is extensive. Now there are plenty of awesome pre-built bikes out there, but for those who like it super-custom, they build it themselves. Also, for tech lovers, it’s a fun project to spec out and build your own bike.
Is Building Your Own Mountain Bike Cheaper?
This is a tough question to answer. If you build a mountain bike with super cheap parts, then you will probably save money. If you bought all the exact same components as a factory made bike, and installed them onto a less expensive frame, you’ll probably save money too. Still, I’m not sure if those are wise ways to save.
Now unless you have money to burn, be careful when building your own bike. If you go for expensive components in every category, the total cost can go through the roof. You can literally spend several thousands of dollars.
I’ve written extensively on MAKE vs BUY an MTB in this Article. What’s better Building vs Buying a Mountain Bike
How Do I Know What kind of MTB Geometries to Choose?
How do you know how much handlebar sweep is right for you? Or what about stem rise? Well, there are some formulas you can try, but there are easier ways. First of all, if your current ride fits you, then use the same geometry. You can make adjustments as you like too.
For instance, let’s say you like your handlebar width, but wish the position was a bit higher. Just go with a stem with more rise and bring the bar closer to you, but keep the handlebar geometry the same.
If you don’t have a bike you like now, test ride already built bikes. Once you find one you like, use the specs as a guide for component selection. This is especially true for frame size and geometry.
Now let’s break down the components in more detail.
Choosing a MTB Frame
The first decision is frame type – hardtail, dual suspension or fat bike. If you are going to do any riding harsher than rail trails, I would go with a dualie.
If you do a lot of riding in sand, mud, snow or soft dirt, then a fat tire bike makes sense. These require a special frame to accommodate the ultra wide tires.
Lastly, a hardtail is fine for all other kinds of riding. Now if you stay strictly on flat pavement with no potholes, you could even decide to ditch the front suspension fork and go rigid.
Rear Derailleur Hanger on a MTB
Even though this is kind of a non-important item, I mention it here since it’s part of the frame more or less. The hanger is a small piece of metal that connects the rear derailleur to the frame. It’s designed to bend or break if you smack the derailleur. This prevents your frame from getting damaged.
The rear Derailleur is an important feature. This simple little item enables upgrades and most importantly provides a replaceable connection to the frame.
Find out more about what a “hanger” is in this ARTICLE.
Wheels and Wheel Sets
If you are thinking about building wheels from all the individual components, you might want to reconsider. Putting together the hub, spokes, and rim require a lot of skill and practice to get it right. For beginner bike builders, it makes sense to shop for pre-built wheel sets.
There are a ton of choices out there. I wouldn’t go for anything too exotic, since spare parts and adjusting tools might incur more expense. Still, you can get a very sweet pair of hoops that use standard spoke and nipple configurations.
The nipples are the tiny bolts that connect the spokes to the rim. By rotating these, the rim can be trued. Also, make sure the wheels you pick fit the cassette you’ll use (the stack of cogs mounted to the rear wheel).
Thru Axle or Quick Release? (QR)
Some readers might not even know what a quick release is as they are rapidly going out of style. These are the axles that help hold the wheel onto the bike. Quick releases (QR) have a lever that you open to remove the wheel from U shaped fork or frame dropouts.
Thru axles are inserted and adjusted through a closed fork or frame loops. This provides for improved stability, safety and handling.
QRs are easier to use and mount to bike racks faster. Still, the safety and performance make thru axles my choice for new bike builds.
Click on Picture for a FREE PDF MTB Build Checklist
MTB Headset Considerations
This might be one of the most unnoticed bike parts until something goes wrong. The headset is a collar-like set of bearings that inserts into the vertical front tube of the bike, and the fork slides inside of it. The headset allows for smooth steering while keeping the steerer tube and fork together working as a single unit.
Threadless headsets are standard on modern MTBs. They are “threadless” because the headset is held together by pressure (not threaded) created by a headset cap bolt which screws into into a star nut in the steerer tube.
Headsets can be funky to install. Consult with a shop tech and watch plenty of online tutorials before diving in.
This is one component that requires time to choose. The problem is that no single fork can do it all. For instance, if you free ride a lot of rough terrain and hit jumps, you’ll need a fork that has a plenty of travel.
If you do mostly cross country riding though, you can get away with a less beefy fork which will also save weight. Make sure the fork is compatible with the wheel size you choose too.
Fork choice is nearly a science in and of itself, and there are various adjustability options. Also, cost can vary widely here – some forks can cost $800 or more. Don’t cut corners too much though as performance counts. Again, consulting with your local shop guru can help point you to the right category.
MTB Rear Suspension
Just like the front fork, the rear suspension has several options. In may cases, the frame may come with a rear shock included. Or the manufacturer may give you a few options to pick from. One of the reasons for this is fit. Rear shocks have tighter specs to fit them into the confines of a dual suspension frame.
If you can get a rear shock that has a lockout, go for it. This lets you nullify the rear suspension which can sap pedal power. You’ll be thankful for this on that long dirt road climb back to the parking lot.
Picking a Mountain Bike Stem
The stem is the short, stubby tube that connects to your bike’s handlebars. The most important part in selecting this component is length and rise (sometimes called angle or height). Most stems can be flipped over to provide drop instead of rise.
The tricky part is that stem requirements are also affected by the frame geometry. A longer frame might warrant a shorter stem and vice versa. Your body geometry also comes into play here.
Here are a couple rules of thumb.
- Cross-country stem: 80-120mm length, up to 30° drop. Places you more over the front of the bike which helps on climbs.
- Trail/Enduro: 50-70mm, 0° or 6° rise. For improved handling in technical terrain.
- Downhill Bikes: 40-50mm direct mount stem that bolts onto the top crown of the fork. Most downhillers opt for 0° rise.
Mountain Bike Handlebar Choices
There are a wide variety of handlebar choices out there in terms of material, diameter, width and geometry. Straighter bars are more popular with the cross country race set, while riser bars (BMX style) are more common for the freerider.
Here material can make a difference in the ride. For instance, the standard aluminum bar may give you a stiffer feel, and it may also transmit more vibration to your hands. A good fork though can smooth out these effects. Carbon fiber and titanium are lighter and absorb vibration better than aluminum, but they’re more expensive.
Bar widths vary from 600mm up to 840mm, and wider bars improve control. You can buy a wider bar and cut it down to the size you prefer.
Groupsets or Individual Components?
For anyone building an MTB for the first time, I recommend installing a groupset. These are a collection of components all from the same manufacturer. For instance, Shimano makes the XT groupset which includes:
- Crank arms
- Bottom bracket
- Front & rear derailleur
- Brake levers
- Disc brake rotors
The best part is that all the parts are designed to work together. If you pick each individual component, you may have compatibility issues. Building a bike piece by piece only leads to frustration if you don’t have experience.
What’s the 1×11 groupset?
Back in the day, you had the rear cassette with 8-9 cogs and the front 3 chainrings. This gave you 24 “gears”, but there was some gear overlap. Now, the new trend is only 1 or 2 chainrings up front and 11 cogs in the rear cassette.
This setup means less shifting up front, less weight and better performance. No matter what component set you use, make sure the wheelset can accommodate the cassette.
Get a Grip On It – MTB Grips
You might think handlebar grips are a minor detail, but think again. Bike contact points are a big deal. Comfort is king, but control is important too. Don’t get caught with fat, cushy grips that make the diameter too big for your hands. On the other hand, thinner handlebars can be compensated for with thicker grips.
Brakes For Your MTB Muild
As I’ve written on other posts, I feel that disc brakes are far superior to other options. Now here you can find some wiggle room in choosing. Shimano offers groupsets that only include the shifting but not brake components.
This means you can try another brand of disc brakes if you like. Formula, Hope, Magura, Hayes, SRAM and Shimano all offer great disc brake groups. If you buy the groupset, everything is included for complete installation.
As another contact point, your seat choice is highly personal. Your sit bones should rest comfortably on the beefiest part of the saddle. Sometimes a seat that has too much cushion doesn’t make the ride better. If it’s too bulky, the seat can interfere with your movement while riding.
MTB seats can be fairly expensive, but they don’t have to be. Typically brand name and weight are the biggest cost factors.
Seat Post and Locking Collar
The first thing to consider about the seat post is fit. Will it fit your frame and seat? Next is material. Like handlebars, seatposts come in aluminum, titanium and carbon fiber. You can opt for a standard seat post which is fine for most rail trail and cross country riding. If you are going to hit more extreme terrain, you might want to install a drop post.
Dropper posts collapse when you activate the handlebar mounted lever. Then, they spring back to the normal riding position. Lowering the seat gives you more clearance for jumps, drops and aerial maneuvers. Drop posts are heavier, so, if you have the money, go for a carbon or hybrid material build to save grams.
The seat post collar fixes the seat post in place in your frame. Some ultra-weight-weenies will look for ways to shave off grams here. Getting a collar with a quick release lever allows for easy height adjustment.
Click on Picture for a FREE PDF MTB Build Checklist
Bottom Brackets for MTBs
Inside the lowest part of the frame lives the bottom bracket. In many ways, this is the heart of the bike. The crank levers attach to this big axle. Don’t skimp on quality here as this component takes a lot of beating. It may come included in a shifting groupset.
Make sure the bottom bracket fis your frame. For most standard frames, a groupset bottom bracket should be compatible.
Cassette, Chain, Derailleurs, Chainrings, Shifters, Cables, Housing, etc.
As I mentioned earlier, these all come in groupsets. For the first -time MTB builder, buying these separately might turn out to be too much to handle.
When it comes time to install the chain, use the length guide usually included with the chain.
This component also is included in groupsets, but you have to choose a length. The standard MTB crank length is 175 mm. Choosing the right length can be complicated. Some experts say it depends on your femur and foot length. Shorter riders may need shorter cranks, but not always.
If you go for a shorter crank, you may lose leverage. To compensate, you might need to change bike gearing. Did I say it’s complicated?
For starters, I recommend going with the standard 175 mm size crank. If you notice problems with knee, calf of back pain, you might swap out.
MTB Pedal Options
As far as I’m concerned, the only two options are clipless or flat. If you already prefer one style, you might just stick to that. Still, trying a different pedal type might open up new riding possibilities to you.
Clipless pedals have a mechanism that locks your MTB shoe into place. You need special cleats and shoes to use clipless pedals.
If your current pedals are in good shape, save some money and just switch them over. Or, buy the other style and try them. If you don’t like them much, you can always switch back. There are a TON of pedal options out there.
I’ve reviewed what I think are the two best options for going CLIPLESS on your mountain bike pedals in this article. Recommended Mountain Bike Pedals
Bike tires for your MTB build
MTB tires can change the characteristics of the ride maybe more than any single component except for the frame and front fork. Your tire choice depends on the terrain you ride.
- Rail trail – Slick or semi-slick.
- Cross country race – Low profile tread especially down the middle. Lightweight.
- Freeride – Aggressive knobs for better traction. Consider sidewall reinforcement.
- Mud – Higher knobs, spread apart for mud shedding. Narrow profile to dig down. Or fat bike tires to float.
Now, you might ride in a variety of situations. You can either change tires for each one (which is a pain) or go for an “all purpose” tire. Still, if freeriding is part of your dirt diet, I would keep those on the rims so you’re never caught off guard.