How to build a bike
in three weeks

How to build a bike in 3 weeks

When my bicycle got stolen from downtown San Francisco, I needed a replacement. I'd been considering building a bike for a while, and with a loaner bike from a friend I didn't need a replacement in a hurry. So, it was time.

There are basically two parts to building a bicycle. First you need to chose a style of frame, and then you need to choose components. As I'd be using my bike to ride around San Francisco I was looking for more of a road bike than a mountain bike, with an emphasis on smooth handling and responsiveness instead of raw speed.

With this in mind, we headed down to the Mission Bicycle Company. Perhaps the most iconic bicycle shop San Francisco. They specialize in single-speed steel-framed bikes for commuting around the city, and very kindly let me test-ride one of their pre-built bikes.

I instantly knew that this was the frame I wanted, it felt light and very responsive, but stable and smooth. Bliss on two wheels.

Mission Bicycle sell two frames, one sized for fixies and single-speed builds, and the other with a wider back fork distance for Shimano internal hubs. We bought the larger frame so that we can upgrade it to a geared bike in the future, but these instructions deal only with building a single-speed.

Week One: Wheels

As the components began to arrive, we realised that we'd need a very large number of specialised tools. For every part of a bicycle (and there are a lot more than I'd realised) there is a specific tool (or sometimes multiple tools) needed to fit it. Thankfully San Francisco came to the rescue again in the form of the Bike Kitchen.

We wanted to scope out the Bike Kitchen with a relatively easy task that didn't require carting a bike frame across the city. So we picked up both wheels, two tyres and two inner tubes, and jumped on the bus.

When we got there it was perfect, 20 people or so all working on their own bike projects, with charismatic, knowledgable volunteers running around helping everyone. We sat in the corner and put together the first parts of the bike.

Putting a tyre onto a wheel

  • 2 700c Wheels (Mission Bicycle, Velocity Deep rims)
  • 2 25x700c Puncture-resistent tyres (Continental Gatorskin)
  • 2 25x700c Inner Tubes with 48mm Presta Valve (Avenir)
  • 3 Tyre levers
  • Bike pump with presta valve
  1. Slightly inflate the inner tubes (so they just hold shape)
  2. Push them inside the tyres
  3. Slip the first part of outer wall of the tyre over the inner lip of the rim, and put the valve through the valve hole in the rim
  4. Lever the rest of the outer wall of the tyre into the rim
  5. Force the first part of the inner wall of the tyre over the inner lip of the rim, being careful not to pinch the inner tube between tyre and rim
  6. Lever the rest of the tyre onto the rim.

We returned home satisfied that we could visit the Bike Kitchen whenever we needed a safe environment with all the bike tools and knowledge that we could hope for. We also had two wheels with tyres on the them! The only other component that had arrived by this point was the pedals, so we spent a bit of time bolting the reflectors onto the pedals.

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Week Two: Headset and Bottom Bracket

As more parts arrived, I began to worry about how everything would be put together. To this end I invested in a copy of the Barnett Manual. This book contains everything you might possibly want to do to a bike, from tapping threads to adjusting brakes.

When you buy a fork not pre-assembled into the frame, the fork will be longer than you need. The only way to fix this is to cut off the excess metal. To find out how much metal is excess you need to measure. We wanted to cut the fork at the Bike Kitchen, but we could do the measuring before we got there.

On Wednesday after a glass of wine, we unpackaged the stem, the headset and the fork, and set to work measuring how much of the fork we'd actually need. This process is a bit fiddly as you need to ensure the fork ends up a few millimeters below the top of the stem, but you can't press all the parts together yet.

When Saturday rolled around, we packed all the components into a bag, hoisted the frame across my shoulder and headed over to the Bike Kitchen.

The first thing we needed to do was cut the fork to length. We started looking around for a hacksaw, put the fork in a clamp and began to saw. Almost immediately we were interrupted by a helpful person with a jig (to help us cut the fork straight). With the help of the jig we finished with a fork exactly the right length (well, +/- 0.5mm), with a flat cut across the top.

The remainder of assembling the front of the bicycle proceeded fairly mechanically (pun intended). We greased all the parts of the headset, fork and head tube, and stuck them together.

Inserting the star-fangled nut

  • Cut-to-length Fork (Mission Bicycle)
  • Star-fangled nut (part of the Headset)
  • Star-nut driver
  • Lots of bike grease (Park Tool PolyLube 1000)
  1. Thoroughly grease the top few cm of the inside of the fork
  2. Screw the star-fangled nut onto the nut driver
  3. Position the nut driver over the end of the fork
  4. Hammer on the nut driver until the nut is about a centimeter down the tube

The star-fangled nut is used to tighten the stem onto the fork, but before that could happen we needed to press the bearing cups onto the head tube. (Before building a bike I'd never considered the idea that I was relying on two sets of bearings just to let the front wheel turn when I move the handlebars)!

Clamping the bearing cups onto the head tube

  • Head tube (part of the frame)
  • Top and Bottom bearing cups (from the headset)
  • Bearing cup press
  1. Grease the inside of the head tube at the top and bottom
  2. Grease the insertable portions of the bearing cups
  3. Put the head tube races into place (with the logos facing forward and the right way up)
  4. Assemble the bearing cup press through the head tube and both cups
  5. Tighten the press slowly ensuring the cups slide into the frame smoothly and straight. Make sure the races sit flush up against the edge of the headtube on all sides so when installed the bearings will align the fork properly.

Now we had all the prerequisites done it was time to assemble the fork and the remaining parts of the headset inside the stem. If all went to plan the fork would extend up to a few millimetersbelow the top of the stem, so that the head tube bolt could grip on the star fangled nut and tighten everything down.

Assemble the fork and headset

  • The fork
  • The headtube
  • The headset
  • Allen key
  1. Grease the crown race seat on the fork
  2. Push the crown race onto the crown race seat
  3. Grease the insides of the bearing cups
  4. Grease the crown race, compression ring, and bearings
  5. Push the bearings into the bearing cups
  6. Slide the fork through the head tube through the bearings
  7. Push the compression ring, washer and dust cover over the fork to the top bearing cup
  8. Grease the exposed part of the fork
  9. Grease the inside of the stem
  10. Slide the stem over the fork (celebrate because the fork is the right length!)
  11. Put the top cap on and ensure the stem and the fork are aligned
  12. Tighten the head tube bolt (to squeeze everything together)
  13. Align and tighten the stem clamp (to hold everything in place)
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All of this surprisingly took us much less time that we'd budgeted, so with an hour left before the Bike Kitchen closed for the day we decided to start work on the bottom bracket.

The bottom bracket joins the pedals to the frame. Just as the headset contains bearings that let the handlebars turn the fork without grating against the frame, the bottom bracket lets the pedals turn smoothly. It's a more complicated mechanical part because it's under much more stress, but they are also sold as contiguous units so you don't need to deal with each part manually.

Inserting the bottom bracket

  • A cartidge bottom bracket with square taper (IRD)
  • The bottom bracket shell (part of the frame)
  • Bottom bracket adaptor
  • Adjustable wrench
  • Allen Key
  1. Thoroughly grease the bottom bracket shell
  2. Grease the threads of the bottom bracket cartridge
  3. Insert the drive train side of the bottom bracket to hand tightness (note the threads are reversed on this side)
  4. Insert the left side bottom bracket cup and tighten it by hand
  5. Tighten the bottom bracket extremely tight using the wrench to hold the bottom bracket tool (ensure the drive train side is flush to the frame, the left side might have to stick out a bit)

That particular Saturday was outrageously hot in San Francisco (over 32°C!) so after finishing the bottom bracket we retired to the relative cool of my apartment and made juice to cool down.We dropped into Cole Hardware on the way home to pick up some bike grease, so we were able to install the crank arms and the pedals (two parts that don't require speciailised tools!) that evening.

Mounting the cranks and pedals

  1. Grease the square tapers
  2. Grease the square holes in the crankset
  3. Slide the left side of the crankset over the taper and hand-tighten the screw
  4. Slide the right side of the crankset over the taper at 180° to the left hand side
  5. Use the allen key to tighten both square taper bolts extremely tight (you don't want any of this stuff to budge when you're pedalling)
  6. Grease the pedal threads and crankset threads
  7. Use the adjustable wrench to tighten the pedals into the crankset.

Week three: Chain, Brakes, etc.

After such a productive weekend, most of the difficult bits of the bike were now done. The remaining things, with the exception of the chain and the brakes, were fairly easy to assemble. And with only a week left in our original estimate we started spending evenings attaching whatever parts had shipped.

On Monday we were able to add both the handlebars and the seat. The seat was one of the most indulgent parts I ordered for this project, the new Brooks Cambium C17. Designed like a classic brooks saddle, with a hammock-like structure, but made of rubber instead of leather. It has excellent reviews, and is extremely comfortable.

  • Saddle (Brooks Cambium)
  • Seat post (Velo Orange)
  1. Attach the seat to the seatpost
  2. Grease the inside of the seat tube
  3. Grease the seat post
  4. Push the seat post down into the seat tube, wiggling it to overcome friction.

The handlebars were the easiest part to assemble, though it was made slightly more complicated because Velo Orange sells Handlebars with a clamp diameter of 25.4mm, but sells stems with a clamp diameter of 31.8mm. This meant we also had to buy spacers (which they helpfully also stock) to make it fit. The other confusing thing with handlebar sizing is that the tube diameter is 22.2mm (except in the middle where it gets wider for the clamp) so we had to order brake levers with 22.2mm clamps.

  • Stem (already attached to the fork)
  • Spacers (grrrrr)
  • Handlebars (Velo Orange)
  • Grips
  1. Clamp the handlebars into the stem using the spacers
  2. Slide the grips onto the ends of the bars

On Tuesday we go Irish Dancing and so it wasn't until Wednesday that we got round to looking at the chain and the backwheel.

Installing the freewheel on the back wheel turns out to be very easy. Because it's designed to get tighter as you pedal, you can just screw it onto the hub finger-tight (after greasing both sides of the threads, of course).

The chain was less simple. The chain has to be assembled on the bike because it goes through the triangle in the frame. It also has to be shortened to the correct length, which is done using a chain tool. Luckily we were building a single-speed bike, because single speed chain is easier to work with than multi-speed chain.

  • Single Speed Chain (SRAM)
  • Chain oil
  • Chain tool (Park)
  1. Put the wheel on the bike and tighten the back axle nuts
  2. Drape the chain around the wheel and crankset
  3. Make the chain taut and mark the link that is too long
  4. Use the chain tool to push out the rivet
  5. Move the back wheel forward to slack the chain
  6. Drape the chain around the wheel again
  7. Link the two ends of the chain with the master link
  8. Move the backwheel back to tension the chain. Make sure the wheel is aligned with the frame before tightening down axle nuts. (Optional: use chain tensioner to pull back wheel back to tension chain, but we didn't find it that helpful.)

When measuring the chain we were careful to pick a length such that when the wheel is at the front of the dropouts the chain is loose and we can take the wheel off. There's not too much slack though and when we use the chain tensioner to tighten the chain the wheel isn't close to the back of the dropouts.

On Thursday we moved on to the final portion of the bike. The Brakes. These are arguably the most critical components. If you stop being able to go, then that's bad; but if you are already going and aren't able to stop, that's really really bad.

Brakes are also amoungst the most complicated things to install correctly. The levers attach to the handlebars easily, but adjusting the brake-pads so that they work correctly is a bit of a palava. Even that is comparatively easy however compared to measuring and cutting the cables.

Assembling the brake system

  • Brake levers (Tektro)
  • Brake cable housing
  • Brakes (Tektro)
  • Allen keys
  • Wire cutters
  • A fine metal file
  1. Attach the brake levers to the handlebars, flush to the grips
  2. Attach the front and rear brakes to the frame
  3. Adjust the brake pads so they align symmetrically with the machined surfaces of the rims
  4. Run the brake cable housing through the frame
  5. Fit the brake cable housing to the levers at the front with the small housing cap
  6. Cut the cable housing so that it fits into the rear brake. Make sure it doesn't go round any sharp bends in the front or rear.
  7. File the end of the cable housing smooth to avoid wearing down the inner cable.

After all of that, we still didn't have functional brakes. The remaining part is to cut the inner cable to size and tighten it to the brakes

Connecting the brakes

  • Assembled brake system
  • Brake cable
  • Wire cutters
  • Allen keys
  • A crimping tool
  1. Cut the end that doesn't match to your brake levers off the inner cable
  2. Slide the cable through the housing (tinning the end of the cable with solder makes it easier to slide through the cable housing)
  3. Attach the cable ferrule end to your brake levers
  4. Open the quick release lever on the brake
  5. Pull the brake lever about a third, pull the cable taught, manually apply the brakes gently.
  6. Clamp the cable into the brakes.
  7. Close the quick release lever
  8. Cut off the excess brake cable (leaving about an inch space)
  9. Crimp the end ferrrule onto the cut end to prevent fraying

And that was it! Everything now done. Just to be safe we re-tightened all the bolts, and then headed outside to try it out.

To cut a long story short (or at least shorter), it all worked! I'm now the proud maker and owner of a very nice bike.

If you want to chat about bikes or need help building one, reach out on Twitter or by email.