How to Build a Bike

How to Build a Bike

Not many people truly build bikes; to do so would be to build the frame, and possibly the components, as well.  I do not have an engineering workshop, nor the expertise to craft what is now a high degree of precision engineering in the design and execution of a modern gear system. There are people who build their own frames, but they are typically building in steel, as aluminium and titanium require a higher level of expertise with welding. And no-one build carbon frames in their garage.

Frame construction aside, the rest is assembly.  For this project I have approached the ideal as closely as possible, designing my own frame to suit my own physical measurements and riding style.  A Chinese titanium engineering company built the frame, and all that remains is for me to assemble the many components into a working bike. 

The build began with the wheels.  Lacing rims is a practised skill, and a good how-to guide is (surprise) found on Sheldon Brown's site.  Even without reading this resource, the keys to success are patience, care, and methodical approach.  There is no real right or wrong lacing pattern - take a look at spoke lacing patterns of different bikes that you see, and a range of possibilities becomes evident.  

My front wheel is an unconventional pattern, with spokes paired at the rim from the same side of the hub, with a double cross-over tension pattern.  Tips that I can mention for wheel-building include these two gems.  To insert a nipple, screw a spare spoke into the flanged end of the nipple, and you can then poke the nipple through the rim hole, and a couple of turns will anchor it onto the wheel spoke.  You can then reverse-turn the spare spoke to release it.

Also, I prefer to lace all of the spokes through the hub first, and then start securing them to the nipples, one set at a time; you have four sets of spokes, two each side of the hub.  Inside-outside lacing, each set anchored at four-hole intervals around the rim.  The lacing pattern comes from the four-hole sequence around the rim holes.

For these two wheels, I used a wheel stand for the entire build, although in the past I have laced the spokes with the rim on my lap, and trued them with the hub mounted in my bike, using the brake pads to spot waves in the rim.  My rear wheel is a traditional lace pattern with alternating left-right hub sides to the rim, and I needed to use the frame to get the dishing centred.  

The rear wheel spokes are asymmetrical, owing to the inset of the freewheel.  Periodically I would dismount the hub, lay the rim across two padded surfaces, and push the hub in to realign the dishing.  A few times around the rim retensioning the spokes, and the rim was done, true and centred.

Now, back to the frame.  First on board was the cable guide.  Being under the bottom bracket and not really visible, it is easy to overlook.  Next, the fork and headset assembly.

Putting the headset, spacers and stem in place on the steering tube, in place in the head tube, Run a pencil around the top edge of the steering tube.  The tube needs to be cut off three mm down from the stem top edge.  To do this properly I knocked up a simple mitre box - three pieces of MDF glued and nailed to another MDF piece, each with a 30 mm hole bored and in line with each other.  To make the cut line visible, wrap a piece of masking tape around the tube, the tape edge along the pencil mark.  Measure 3 mm down from the edge of the tape, marking points as you rotate the tube.  Join the dots, and you have a cut line.  With the tube secured in the mitre box score around the tube with a fine-tooth hacksaw blade, and keep rotating the tube as you cut deeper.  When the tube is cut through, use a fine metal file to smooth down the rough edges, and then fold some 1000 grit sandpaper around the edge and smooth the edge flat, inside and out.

When reassembled, the top cap fits down into the 3 mm space between the top of the tube and the top of the stem.  The compression plug keeps it all nice and tight.  You can then tighten the stem, and bolt the bars to the front of the stem.  Suddenly, it begins to look like a bike...

The rear derailleur can be bolted on at any time, so now is good.  Before positioning the front derailleur, you must install the bottom bracket, and then the crankset.  You can now secure the front unit the correct distance from the top of the crank.

The brakes go on next.  It is always good to get the back end cable mounts in place first.  With the brakes on, slip the shifters onto the bars and tighten them into position.  You can now install the cables.  Now, mount the wheels into the drop-outs, with the cassette installed on the rear freewheel.

Mount the brake cables first, and hold the housings in place against the handlebar position grooves with a couple of turns of electrical tape.  Always get the housing cut with a cm to spare, so if you stuff up a housing cut you can still tidy it up.  When you cut the housing (always before pushing the cable through!) use a spoke to open up the squashed housing core.  Simply push the threaded end in and give it a couple of turns.  Run some grease over the length of the cable before you push it through.  

Secure the cable to the brakes, and ALWAYS read the manufacturer's instruction paper before doing anything.  This also give instructions on how to correctly set the cable tension.  Test the lever-brake action, and then cut the cable with about 5-7 cm to spare, and use some pliers to crimp the aluminium end cap onto the end of the cable.

Before connecting the gear cables, follow the manufacturer's instructions to set the top and bottom limits for the derailleurs. Install the chain, making sure that you have the right number of links (rear derailleur instructions have clear notes on how to do this for your own set-up).  For my build, I ended up removing four links.  You can now connect the gear cables, and if you have not taken any short-cuts the gears will need minimal tuning.  Mine needed a minor tweak to the rear cable barrel-end adjuster, and all was good, shifting up and down cleanly and positively.

All that remains is the cosmetic and practical bits.  RIm tape, tubes and tyres, saddle, seatpost and clamp, handlebar tape, and pedals.  All done, the bike is now assembled.

So, how does it ride?  Very smooth, and the fit is spot on.  After the first ride (93 km) I felt no fatigue at all, almost as if I hadn't been for a ride at all.  One would expect this, as I designed the bike to match my own physical measurements and riding style.  And that is something that you can only really achieve with a professional bike fit service, finding a bike to suit you.  I could quite likely have achieved a similar ride by finding a bike of the right size frame, and tweaking the set up to suit, but then, I would not be able to say that it was my bike - designed and assembled by myself - would I?

It's a Fit-Up Job - Framed!

It's a Fit-Up Job - Framed!

A top-end carbon frame, with the same four
points as the Pedersen bike

Straight up, the frame is the heart and soul of any bike.  There are four main points - the head tube anchor for the steering, the saddle, bottom bracket for the crank, and the rear wheel dropouts.  If you plot those points on a piece of paper, you can then draw any means of connecting them.  The traditional diamond frame developed quite early in bike history, and remains the basic layout for the majority of bikes.  There have been experimental departures from the diamond frame, but they are rare, short-lived and frequently expensive; how they perform is often enhanced, but at a premium.

A frame can make or break a bike.  The materials used, tube lengths, union angles.  Each can subtly influence the feel of the ride, how you sit and ride, comfort over long rides, power transmission from legs to wheels.  How stiff is the frame?  Will it flex along its length, reducing stability around corners, or will it be so stiff that every bump and vibration is transmitted straight up to your backside, spine and wrists?  Materials, tube lengths and geometry define a frame and its performance, and that is what makes the name on the frame marketable.

If you ever buy a bike from a shop, or read reviews about bikes, one thing becomes clear - the group set, the wheels, bars, and anything else attached to the frame, are off-the-shelf items, all interchangeable.  What makes a bike unique to a brand is primarily the frame, and secondly what particular combination of components is used to make it work.  

Simply, you can have two or more different bikes from different companies, but all sharing the same components.  There is no such thing as brand-loyalty; what distinguishes brands is the frame design - tube lengths and angles, materials and dimensions.  Many riders know this fundamental truth, and build their own bikes, choosing the frame and components to suit.

When I began this project, my original intention had been to source a stock frame from an online dealer.  That plan changed.

The shift began when I was researching what stem to buy.  This is reasonably important, as for a bike set-up there are two aspects of a bike that can be controlled to alter the reach (distance from seat to handlebars).  These are the seat position - a few centimetres slide along the rails.  The other is stem length.  To get the right stem length from the start, I used an online bike-fit calculator.

My dimensions and fit calculator output.

There are a few pages that will give you the set-up dimensions that best suit your body and style.  The calculator that I used is at Competitive Cyclist.  There are other sites, and when I enter the same measurements they give equivalent results, so one can assume they are trustworthy.  besides, I have based a significant investment in that assumption.  Simply, the fit calculator leads you through a range of body measurements, with clear instructions on how to make the measurements accurately.  Follow the instructions, enter your numbers, and it gives you essential dimensions of both frame tubes and controllable set-up aspects for your own body, with choice of up to three different riding styles.

All good so far.  It gave me the correct stem length, and tube lengths for a frame.  So, what frame?  Regular searching online gave a range of frames and prices, ranging from steel audax frames and bare aluminium frames for really, very low prices, though to labelled carbon frames in excess of NZ$3000.  There were also some titanium frames out there (Lynskey frames, from NZ$2000 onwards).  Of note were some naked carbon frames from Asian factories selling direct online.

The pieces of a Trek carbon frame.
Before being glued together.

Thinking time - what frame material?  There is often an automatic assumption that carbon is the top-line material; all cyclists should aspire to a carbon frame. Yet there are many steel frames out there, many being made and sold new.  And carbon breaks in a crash (recall, I bought alloy handle bars because alloy will not break either in a crash or spontaneously from progressive strain and delamination).  A quick check showed that most carbon frames come in at around 1.2 to 1.7 kg bare weight.  If not carbon, then we are talking metal.

Metal frames have a characteristic called "yield".  Simply, if you ride over a bump the frame bends slightly, absorbing the impact, and its elasticity returns the frame to its original shape quickly.  This gives metal frames a smooth ride.  Steel is the strongest material, but is also the heaviest.  It can take a lot of punishment, and a well-crafted frame can still perform better under a pro cyclist than a standard carbon rig.  Aluminium is still tremendously popular, as it is very light.  Aluminium's drawback is its low strength compared to steel (its modulus is 30% that of steel - described in detail on the late Sheldon Brown's site), so to have comparable strength the tubes must be of greater width or thickness than steel, although the resulting frame is still much lighter than a comparable steel frame.

And then we get to Titanium.  Titanium had a brief reign as the ultimate frame material, dethroned by the introduction of lower-cost carbon once the industry became capable of producing large-volume runs of carbon frames - it was always a matter of time.  In terms of metal, Titanium alloy is almost as strong as steel, and almost as light as aluminium.  If you built two frames of identical tubing, one of steel and one of Titanium, they would be of similar strength, but the Ti frame would be half the weight, and half as stiff, so to compensate for the stiffness a thicker-walled tube is used.

So, all things considered, Ti makes sense.  I would get the smoothness of metal with the lightness of carbon, and it would never break, fatigue or have issues with progressive delamination of the fibre layers. A quick search on Alibaba revealed several Asian factories producing titanium frames.  An initial email query gave the response "$X for a frame, add $100 if we make one to your own design."

Own design.  I liked the sound of that.  The bike would truly be a personal ride.  So, how do I design a bike?  There has to be something on the web about how to do it.  The search gave the answer within seconds:  BikeCAD.  

BikeCAD is an online Java-based CAD application that has been developed by Bike Forest, a bespoke bike design company.  The free version, despite some limitations, allowed me to create my own frame design, incorporating all important details beyond the obvious tube lengths and angles.  Every dimension is tunable, and many key components, for example headsets and pedals, have industry-standard units pre-programmed, with design dimensions adjusted to suit.  

My bike design overview.

A lot of tweaking, double-checking, cross-referencing and tweaking again gave me my frame design; using the bike fit key dimensions and my known components, and visual look (less compact and more traditional geometry - a blend of the two).  I then emailed the link to the CAD online file, a pdf of the design, and summary details of finer aspects of the frame to a few of the Chinese factories, collected quotes and haggled by email.

Some businesses don't want my business - slow replying (if at all), poor communication and little interest shown.  A couple of others were right on the ball - fast turnaround on replies, questioning anything that was ambiguous (often arising from Kiwi English to Second-Language English).  The business that impressed me the most was Xi'An Changda Titanium Products Company Ltd.   The rep took my CAD portfolio and created the factory AutoCAD version, made some tweaks, and made some last-minute adjustments to the head tube design once I had the headset and tube matched up and remeasured.  According to the company information the business was one of many set up by the Chinese government to support their developing aerospace industry and space program.  Making other titanium products, including bike parts, is just a part of their diversification.

Not quite the cheapest, but to get the order they lowered their price, quoting a total of NZ$1029.20 made and delivered.  So, that is less than half the price of a generic Ti frame, and made to my own design.  Compared to carbon frames, the price is similar to a mid-range generic frame, again not of my own design.

The frame arrived inside a few weeks, and I had the head tube reamed by a local engineering firm to ensure the integrity of the headset fit.  A wee oversight in the plan was the downtube mounts for shifter levers, but a pair of aluminium cable stops with barrel adjusters from the eBay seller chn_chou (NZ$24.29) not only fixed that issue, but improved upon it, placing the cables a bit further away from the downtube, and allowing an extra degree of tension adjustment.

Every bike needs a name, and after searching the net for examples of some appropriate names - protocol4, helix, halo, paradigm - they are all already being used.  Words lead on from each other, and recusant seems more appropriate, describing as it does a person who does not follow the mainstream.  In the past the word was also applied to heretics, who were often burned at a stake.  Hence the image for the headtube.  Adding Ti to the end identifies the frame material, and gives an Italian ring to it.



Frame decals were from Bikenames.com, and the frame finished with polyurethane clearcoat, the formulation for alloy wheelrims.  This is a durable, hard-wearing spray that is made to by applied directly to metal without a pigmented primer.  Final wet sanding with 1000 grit and a polish, and the frame is done.

Lovely.  Now I have to put it all together...