How to Build a Carbon Race Bike From Scratch on a Budget

Hi everyone,

Modern carbon race bikes are amazing machines... but have you seen the prices lately? A high-end road bike from a big brand now easily costs €6,000 to €9,000. That's more than many motorcycles!

So I asked myself a simple question: how close can you get to that kind of bike by building it yourself, from a bare frame, with carefully chosen parts?

The answer: very, very close. The bike in this Instructable is a full carbon aero race bike with carbon wheels, a 2x12 speed groupset, hydraulic disc brakes, a power meter and a GPS computer. It weighs 7.6 kg in size L (real weight, on my scale, without pedals) and cost me €1,559 in total.

In this Instructable I'll show you how to choose the frame, how to choose the components so that everything is compatible, and the right order to assemble everything, even if you've never built a bike before.

Just like with motorcycles, many people think you need a pro workshop for this. This is not true! I built this bike at home, with basic tools, and if you can follow a torque value, you can do it too :)

Building time: a relaxed weekend, around 8 to 10 hours

Difficulty: medium. No special skills needed, only patience. You'll learn everything in the process!

Tools needed:

1. A set of hex (allen) keys, and a torque wrench (this one is NOT optional with carbon parts)
2. Carbon assembly paste and some grease
3. A saw guide and a hacksaw with a carbon blade (to cut the fork steerer)
4. A cable cutter, and a hose cutter for the brake hoses
5. A bottom bracket tool matching your BB (T47 in my case)
6. A cassette lockring tool and a chain tool
7. A bleed kit for your brakes
8. An internal cable routing kit (the magnet ones are cheap and will save you hours!)
9. A bike stand helps a lot, but is not mandatory

The complete parts list with links is in Step 3. Prices on AliExpress change all the time, so I prefer sharing the links than fixed prices, this way you'll always see the current ones.

I filmed the whole build, so here is the full video! It shows every step of this Instructable, plus the complete price investigation: where the money really goes when you buy a big brand bike, and what you actually lose (or not!) with a build like this one.

You can watch it before or after reading the steps :)

This is the most important decision of the project, as everything else will depend on it.

For a race bike, we want carbon: it's light, stiff and comfortable. The problem is that a carbon frameset from a famous brand costs €3,000 to €5,000 alone. So we're going to look at where most of the carbon frames in the world are made anyway: China.

Now, this is very important, because there are 2 very different things you'll find there:

- Real Chinese brands. Trifox, Winspace, Yoeleo, Elves, etc. These are real companies, with their own names on their own frames, their own molds or open molds they are allowed to sell, a warranty, a customer service and a reputation to protect. This is what we want.

- Counterfeits. Fake "Pinarello", "Specialized" or "Cervélo" frames sold for €500. Stay away from those, always. You have no idea how they were made or tested, there is zero warranty, and we're talking about the part holding you at 70 kph downhill. On top of that, it's simply stealing the work of the engineers who designed the real one, and it's illegal to import in most countries. Don't buy them, and don't help this business exist.

I went for a Trifox X11. The frame kit includes the frame, fork, seatpost and a one-piece carbon aero cockpit, for €651 at public price. My size L frame weighs 1,035 g on the scale.

I chose the Trifox one because the price was quite affordable, and it including almost everything: the integrated handlebars, steering bearings, the T47 bottom bracket, the UDH and so on. And also it was shipped free and duties included to France.

The link of the frame kit is here.

Make sure to check this because in many case from sellers from Aliexpress, you may have to pay custom duties. It really depends on the seller and their method of shipping.

What to check before buying any frame:

1. The geometry, not the size letter! Compare the stack and reach numbers with a bike that fits you. My X11 in L is 580 / 398 mm, which is almost exactly the same as a Giant TCR or a Canyon Ultimate in the same size.
2. The standards, because they decide which parts will fit: bottom bracket type (T47 threaded on mine, much easier to live with than press-fit), brake mounts (flat mount), axles (12 mm thru-axles), derailleur hanger (UDH is great, you'll find a spare one anywhere) and tire clearance.
3. If the cockpit is integrated, choose its width and stem length when ordering. Don't just take the default one!

Don't be in a hurry here. Write all those standards down, we'll need them in the next step.

Now the fun part: shopping! The rule is simple: every part has to match the standards of your frame and of the other parts. Here is how I chose mine.

The groupset. The standard today on race bikes is 2x12 speed with hydraulic disc brakes. Electronic shifting is nice, but it's also where the price explodes. To stay on budget I went for mechanical shifting, and honestly a well adjusted mechanical groupset shifts great.

This is also where Chinese brands became really interesting these last years. L-TWOO and Sensah make complete 12 speed groupsets for a fraction of the price of the big names, and the performance is surprisingly good. I chose the L-TWOO RX 2x12, mechanical shifting with hydraulic brakes.

The wheels. This is the best upgrade you can put on a bike, so don't go too cheap here. I chose CSC D272 carbon wheels, 50 mm deep, with hooked rims (they work with any standard tire) and a 54T ratchet hub. Check 3 things: the axle standard, Center Lock or 6-bolt rotors, and the freehub body, which has to match your cassette.

If you were to buy some similar wheels with same specs from a western brand, it would cost you around €2000, so the chinese wheels are about 8 times cheaper.

The rest of my build:

1. Crankset with power meter: GEOID PM500, 165 mm, with 50/34 chainrings
2. Cassette: Goldix 11-32, 12 speed
3. Chain: Shimano SLX 12 speed (chains are cheap, go for a famous brand)
4. Rotors: ZRACE Center Lock, 160 mm front / 140 mm rear
5. Tires: Michelin Power Cup 28c with TPU inner tubes. Tires are what keeps you on the road, never save money here!
6. Saddle: RYET 3D printed with carbon rails
7. Computer: GEOID CC700 Pro
8. EVA bar tape, bottle cages, and a T47 bottom bracket matching the crank spindle

Compatibility traps I ran into, so you don't have to:

1. My power meter spider uses a symetric 4-bolt 110 BCD pattern. Shimano chainrings are asymmetric and will not fit! I used Magene chainrings instead.
2. Check the total capacity of your rear derailleur against your cassette and chainrings (37T on mine).
3. My frame is size L so I needed a quite long rear derailleur cable housing, I got a 1700mm and it was almost too short, make sure to get long ones ;)
4. Carbon saddle rails are oval (7x9 mm). Make sure your seatpost clamp accepts them.

Do not be too ambitious! It's tempting to chase the lightest, most exotic part for every single line of the list. Go for parts that are proven and well reviewed. You can always upgrade later ;)

The real job starts now! And we start with the most tedious part, so after this, everything gets easier.

First tip: put the seatpost in the frame right away (with carbon paste), and clamp your bike stand on the seatpost, never on a carbon frame tube.

1 - Route everything through the frame while it's still empty. The rear brake hose and the two shift housings go from the head tube to their exit points. This is where the magnet routing kit is worth every cent. Leave a lot of extra length at the front, we'll cut later. Another tip: slide some foam sleeves over the hoses inside the frame, so nothing will rattle on bad roads.

2 - Dry fit the fork. Grease the headset bearings, slide the fork in, add the spacers and the cockpit, without any cable for now. Put all the spacers you think you might need, then mark the steerer about 3 mm below the top of the stem.

3 - Cut the steerer. I know, cutting a carbon fork sounds scary, but it's actually easy:

1. Measure twice, cut once. You can always cut more later, you can never add some back! If you're not sure about your position, keep more spacers for now.
2. Wrap masking tape around the cut line to avoid splinters, and clamp the saw guide on it.
3. Use a carbon blade (or a fine metal blade), and cut slowly without pushing.
4. Wear a mask and gloves, carbon dust is nasty. Wetting the blade a little keeps the dust down.
5. Lightly sand the edge, then install the expander plug at the right torque.

4 - Route through the cockpit. Now feed the hoses and housings through the headset parts and the integrated bar, up to where the levers will be. Take a photo of your spacer stack before taking it apart, you'll thank me later. Then mount everything for good and preload the headset: no play, but the bar still turns freely.

Here is the order I recommend:

- Rear derailleur first, bolted on the hanger.

- The wheels: mount the cassette, the rotors (lockring at the right torque), the tires and tubes, then put the wheels in the frame. Tip for TPU tubes: never inflate them outside of the tire, they'll deform.

- The levers, and this matters: place them now in the position you actually want to ride, even roughly. The final length of your hoses and housings depends on it. Many people do this at the very end and then everything is too short or too long.

- The bottom bracket. Clean and grease the threads, and screw the cups by hand first, they should go in easily. On a T47, like on a BSA, the drive side is reverse-threaded, the direction is printed on the cups. Then torque it.

- The crankset, then the front derailleur: cage parallel to the chainrings, 1 to 3 mm above the teeth of the big one.

- The chain. For the length: wrap it around the big chainring and the biggest sprocket, without going through the derailleur, and add 2 links. Cut, and close it with the quick link.

- Shift cables and adjustment: cut the housings to length, pull the cables, then set the limit screws first, then the B-tension, then the indexing with the barrel adjuster.

Don't worry if the shifting is not perfect at the first try, it's only about small quarter turns on the barrel adjuster. It is actually easier than it sounds!

It's one thing to get a bike to move, it's another to get it to stop! Take your time on this step.

My hoses needed to be cut and I bled the whole system myself. Here is the process:

1. With the levers in their final position, turn the bar fully left and right, and cut each hose so it's just long enough. Use a real hose cutter for a clean, square cut.
2. Install a new barb and olive on each hose, and tighten the fitting at the right torque.
3. Bleed the brakes with the fluid specified for your groupset [mineral oil for L-TWOO, confirm on your kit]. Never mix mineral oil and DOT fluid! Push the fluid from the caliper up to the lever and tap the hoses to chase the bubbles. The lever should feel firm, not spongy.
4. To center a caliper: loosen its 2 bolts, squeeze the lever hard, and tighten the bolts while holding it. Spin the wheel, there should be no rubbing.
5. Keep any oil away from pads and rotors, and clean the rotors with isopropyl alcohol before riding.

We're almost there!

1. Mount the saddle, level, and set your saddle height. Carbon paste on the seatpost, and respect the torque of the clamp.
2. Confirm the final position of the levers. Both at the same height!
3. Only now, wrap the bar tape. It goes on last because once it's on, you don't want to touch anything under it anymore.
4. Mount the computer, the bottle cages and the pedals.

And the key rule of the whole build, same as on a motorcycle engine: tightening torques! Every carbon part has its torque printed on it or in its manual, usually just a few Nm. Too loose, things slip. Too tight, you crack carbon. Use the torque wrench, every time.

Are you ready for it??

This has to be the most exciting part. But before the first real ride:

1. Check every bolt one more time with the torque wrench
2. Bed in the brakes: around 20 firm slowdowns from 30 kph to walking speed, without locking the wheels. The brakes are weak before that, this is normal!
3. Start with a short, easy ride near home, and test all the gears and the brakes

After the first 50 km, re-check everything: all the bolts, the headset play, and the indexing. New cables always settle a bit, so a small turn of the barrel adjuster is normal.

So, how does it ride? I've done several rides on it now, including a 100 km one with 1,000 m of climbing, and I have nothing to complain about. It's stiff, it's fast, and it's super comfortable. I was riding with people on bikes costing more than €6,000, and my bike was their equal everywhere: climbs, descents, flat. No one could tell.

I have also raced two triathlon with the bike, and I was passing a lot of people on expensive TT bikes, which really proves that this one is more than enough for me :)

Attached is the full comparison I made with a Giant TCR and a Canyon Ultimate CFR, equipped the same way (carbon wheels, power meter, computer, 3D saddle). Almost the same geometry, less than 1 kg of difference with a €8,750 bike... and around €7,000 saved. All the details are in the video ;)

Needless to say: always ride with a helmet, and ride within your abilities.

I hope this Instructable will make some of you take the plunge. Building your own bike is not only about saving money: you'll know every single bolt of it, you'll be able to fix anything on it yourself, and you'll be proud every time you ride it.

I said it years ago about my cafe racer, and it's still true with pedals: if you like riding something you've bought, try riding something you've built... ;)

-Tom