Frame building basics #2.2 - Steel

Good quality and affordable steel has really transformed our world. In addition to being used for cars and motorcycles, quality materials have found their way onto bicycles aswell.

There are so many different steels (alloyed and non-alloyed) that I am going to try to describe three main types of steel and bring out a few examples.

• low carbon steel. Very affordable, average strength and fairly workable (cutting and machining). Very weldable and does not need artificial aging and hardening. Main alloying elements are Manganese and Carbon. For example 1010 steel.
• Alloyed steel. Fairly expensive, can be extremely strong. Difficult to work (cutting and machining). Fairly weldable, does need aging, but not tempering/hardening post welding. Main alloying elements are Chromium, Molybdenum, Carbon and Manganese. For example 4140 low alloy steel.
• Corrosion resistant steel. Fairly expensive, can be very strong. Difficult to work (cutting and machining). Fairly weldable (needs purging gas). Main alloying elements are Chromium and Nickel. For example 304 stainless steel.

Frame building basics #2.1 Aluminium (Aluminum)

Aluminium rose into the world arena after they developed a way to separate it from the ore using electricity .

There are numerous alloys used in frames and related parts and each have specific characteristics that suit specific needs. I will list below a few common alloys used in parts and what their properties are:

• 6061/6063 – a very very common alloy which is used to make bicycle frames and parts. It is very weldable and very workable. Has very good corrosion resistance and can be artificially aged and precipitation hardened. Can be extruded very well. Main alloying element is Silicon.
• 6105/6106 – a very common alloy used for rims. Has similar properties to 6061(has higher tensile strength), has a little bit more silicon in it, can be aged and precipitation hardened. Can be extruded very well. Slightly inferior workability compared to 6061. Main alloying element is Silicon.
• 7005 – used in bicycle frame prodction. Very strong (high tensile strength), also expensive and moderatly easy to weld. Inferior manufacturability compared to 6000 series alloys. Does not need to be precipitation hardened after welding. Average corrosion resistance. Main alloying element is Zinc and Magnesium.
• 7075 – used in parts production, very strong(comparable to steels), very expensive and hard material to machine. Used in places where weight is important, but loss in strength is not allowable. Should be artificially aged and precipitation hardened after welding. Main alloying element is Zinc and Magnesium.

This covers some of the aluminium alloys used in todays bicycles. 7005 series aluminium frames are a lot less frequent, since most companies have migrated to 6061-6063 aluminium. Those two are also most commonly found at different metal tubing resellers /warehouses.

Since 6061-6063 are the most common alloys out there, I am going to assume that you are interested in using them to make a custom frame. I would recommend using 6061-T6 aluminium (slightly higher tensile strength compared to 6063-T6). It is available in many different tube sizes/shapes, is easy to manipulate even with basic tools and can be polished very well.

But before embarking on a frame building adventure (which involved 6061-T6 aluminium), there are three very important questions to answer:

• Do I have somebody nearby who can Tig weld 6000 series aluminium really well?
• Do I have access to tubes that have similar sidewall thicknesses ?
• Do I have access to somebody who specializes in heat-treating /aging /precipitation hardening aluminium alloys?

- Question nr 1 is relatively easy to answer and people can usually recommend a good welder nearby. An average bicycle frame takes around 1-1.5 hours to weld up (personal experience).

 - Question nr 2 is also relatively easy – having tubes with similar sidewall thicknesses helps the welder. Having a tube which is 2mm and other which is 1.5mm does not seem like a big issue, but there is a thickness difference of 33%. In amperage that means 85-90 ampers for the 2mm tube, but 65-70 ampers for the 1.5mm tube. Easier to burn through tubes and also extends the HAZ (heat affected zone) outwards more than needed.

 - Question 3 is the biggest decider in my opinion. If you have somebody nearby who can help you and can do the whole process for 50-100 usd, I'd say go for it. The reason why I had to drop aluminium as a frame material was the high cost (was quoted around 500 usd) of post-welding processing.

Bicycle chain combatibility - chains,widths, gears and more

Chain combatibility for 5, 6 and 7 gear bicycles (10,12,14 or 15,18 and 21 gear bicycles) can be confusing to say the least.

Bicycle chains are made according to two(three) common standards , 1/8 and 3/32 of an inch in size(3.175mm and 2.38mm respectively). 1/8ths chains are usually reserved for single speed, BMX and other similar applications. This is mainly due to the fact that a chain that size has very thick links and does not bend/flex very well.

The thinner chain (3/32) is used for for bicycles that have up to 21 gears (3 chainrings in front, 8 in back). If your bicycle has 5 gears in the back and 2 in the front, you can easily buy a 7-speed chain and use it successfully(just make sure the cassette/freewheel gears have not worn out too much, otherwise the new chain might start skipping).

There are several sizes of chain available, but they all share one feature in common – they link length from center to center is 1/2 inch (half an inch, 12.7mm). The common thicknesses are listed below:

1/8 – BMX, singlespeed, biketrials

3/32 – bicycles with cassettes/freewheeles, between 5 and 8 gears in the rear

11/128 – bicycles with cassettes, between 9 and 11 gears in the rear

Since there are many types of bicycles out there, there are also a host of different sizes, uses and coatings available that help prolong chain-life and keep systems running longer. Check from your local bikes hop or online to see which chain matches up with your bicycle. Having the right chain makes sure that you also have the best performance and reliability.

How to set up a bicycle for commuting - brakes, gears, tires and more

Commuting is becoming more and more popular but many bicycles are not exactly set up for it. If you have a lot of money, you can buy a custom made commuter bicycle, which can cost you 2000 usd/ 1800 eur easily.

If you don't want to spend that kind of money and you have a good bike already at home, here are some suggestions to make your bike ready for the long haul.

 - Bicycle computer

• this is extemely important since it helps you track how many miles you are travelling. Calories and average speed is fun, but knowing how many kilometers you've done on your cassette, chain and tires allows you to prevent reliability issues and keep you happy

 - Brakes

• buy some wet-weather brake pads. They work great during dry times aswell, but especially well in wet conditions
• replace cable housings. Instead of having 3 separate pieces of cable housing, remove them and put 1 long housing piece instead. The brakes may feel a little bit „squishy“ but all that dirt, water and other garbage is kept out and the brakes work really well for a long time. Also, if you want to make sure it works well without corrosion put a few drops of wet weather chain lube in the cable housing when assembling.
• Replace cables with either stainless ones or teflon (PTFE) coated ones. This makes a huge difference in reliability and allows the cable to slide better inside the cable housing.

 - Gears

• having 30 speed gear system is fun, but also needs you attention more often. Having a computer to record your kilometrage can help prevent serious issues down the line.
• When changing a chain which has done 1500km or even more, consider changing the cassette aswell. When a new chain is put on an old cassette it can cause the chain to skip over the gears(due to the cassette being worn to a different profile) and also premature heavy wear (you might only get 750km out of the new chain, instead of 1500km).
• I've seen well maintained gear trains which have done 2500km+ and the gears dont skip and cassette looks fine (even though the chain is stretched). I've also seen poorly maintained gear trains which have done barely 1000 km and need to be replaced due to the fact that the owner had not put any oil on the chain, cleaned to chain or adjust gears so they run properly.
• For wet season get wet weather chain lube, for dry weather get dy weather chain lube. Check your chain every 2-3 weeks to see how it's doing.
• Properly adjusted and tensioned gear train should work really well for a time – get it checked at least every 6 months or so. Having properly adjusted gears increases efficiency and keeps the whole system from wearing down too soon. Also it sounds nicer :)

 - Tires

• consider investing into quality tires that can run you for a long time without flats and without wearing out. Schwalbe Marathon Plus tires are in my opinion still the best tires out there. While they cost around 50 usd / 45 eur per tire, they havea a guarantee of 5 years, 5000km. I worked for a bicycle rental shop a few years back and after switching all their bikes over to Marathon Plus tires, they went from ~100 flats per year to 2 flats per year. One of those flats was caused by a 4 inch nail
• having quality inner tubes can make a huge difference if you can't get quality puncture proof tires. Regular inner tubes have a side wall thickness of about 1.25-1.5mm which is okay for most uses. For extra protection consider getting DH (downhill) rated inner tubes. They have a wall thickness of 4-5mm and come in a lovely green color. They are practically impossible to break and when combined with puncture proof tires, they are the the best option out there.
• Don't get tubeless(unless you run them with inner tubes)

 

 - Good practices on grease usage

Grease holds a very important place in bicycles, it is used to protect bearings (headset, hubs, bottom bracket) and other mechanisms( shifter bodies etc). The type of grease is as important as it's use.

Grease also helps to keep away corrosion and keep parts moving freely (so parts do not get stuck)

Using grease that is meant for bearings is acceptable but it is always recommended to use special grease for bicycles. Usually bicycle grease runs in faster and is a bit more weather resistant.

On top of having regular grease, there are also speciality grease available for performance hubs, ceramic bearings, suspension fork seals and for shifter bodies (internal mechanisms).

When I rebuild a hub, I generally put more than less grease in for several reasons – it will protect the ball bearings, it will help the hub run longer(without wearing out) and keep corrosion away. I should point out that having the bearings submerged in grease is a total overkill aswell – it will initially be less efficient and takes longer to run a hub in.

If you are using your bicycle every day for the whole year (snow, rain etc) I would actually look away from bicycle grease and focus on marine grade bearing grease. It's very resistant to salt found during the winter and has a nice blue/red color. While the marine grade grease takes longer to run in, it lasts longer and can last up to 2-3 years before needing to be changed out( assuming you travel atleast 4000-5000 km per year).

Frame building basics #2.0 - materials, utilization and ease of manufacture

Bicycle frames these days are mainly made from steel and aluminium. There are advantages and disadvantages for both, but either are used extensively.

- Aluminium

There are different alloys available for both aluminium and steel. For example an aluminium frame can be made from 6061 aluminium, but handlebars are made from 7021 and rims made from 6106 series alloy. Different alloys have different properties that work for very well for certain applications, but not overly well in others. Some areas need extraordinary stiffness, others need to be flexible to make sure the parts don't shatter under load.

Aluminium frames are considered stiff, light but having shorter „lives“, due to the fact that the material/alloy has a limited number of cycles of use(1 million for aluminium, 7-10 million for steel, 12 million+ for titanium etc).

 

- Steel

For steel, it's a bit more tricky – there are many different alloyed and non-alloyed materials available + proprietary materials.

For example, most frames might have a marking of „HI-TEN“ steel – this basically means it is made out of a material that has high tensile strength. It does not certify/quantify what is considered high.

Some of the more common steel based materials can be classified as low-carbon steel (none to very little alloying elements), low-/alloyed steel (cr-mo steel) and corrosion resistant steels ( stainless, 304 or 316 series). Low carbon steel is the weakest of the bunch but also the cheapest to use (and easiest to manufacture with), while stainless steel frames take a lot more work to make them - tougher material and while welding the frame needs to be purged (cleaned out, argon is flooded in to replace regular air mixture to avoid cracks, porosity and poor weld beads).

- Excotic materials

There are also more exotic materials available – titanium, carbon fibre and bamboo/fibreglass.

Titanium is the most expensive of the bunch, where custom frames start from 800 usd / 720 eur upward with wait times of months. The most commonly used alloy is TI6AL4V, where titanium is alloyed with aluminium and vanadium.

Carbon fibre has become a lot more prevalent is the bicycle world and even rather cheap bikes have full carbon frames. Carbon can be a finnicky material, but if you take good care of your bicycle, it will be just as strong as a steel frame.
Carbon fibre frames can be built at home, but you need some specialized equipment for best results - a low pressure capable vessel, availability of good epoxy (West system) and good quality carbon fibre cloth. I will always recommend using unidirectional twill cloth. There are also videos on youtube that show how to lay up layers for areas that need it more.
 

Last but not least, there are frame made from bamboo and fibreglass. I have not first-hand experience with them, but from what I've understood, they are fun to ride and pretty durable.

Bicycle tire sizing guide - sizes, dimensions and uses

- Introduction into tire sizing for bicycles

Bicycles tires have gone through a big leap over the last 15 years, there are new sizes available and also special tires for very special applications.

I believe the two most common sizes are 26 and 28 inches. The ISO ERD sizes would be for example 54-559 and 35-622 respectively. Here's what these numbers mean:

54 – tire width in mm (just an example size)

559 – ERD or effective rim diameter. This is the size of the tire that sits on the rim and is not the real diameter of the wheel.

The inch system is similar, but dimensions are given this way: 26x2.2 (26 inches ERD and 2.2 inches width).

 - Buying tires and planning ahead

When planning on getting new tires, there are several things to check – dimension, tread type and tread width. On some cheaper tyres, the width might be stated as 2.2 inches / 54mm, but the tread may be sticking out quite a bit more. This is especially important for city/trekking bicycles as they have narrow chainstays and the tire may start rubbing the frame (and this will eventually wear the paint off and might even damage the frame, regardless of being aluminium/steel).

 

 - Punture proof, puncture resistant - what does it mean?

In terms of protection, there are 3 types of tires available: no protection, puncture resistant and puncture proof. 99% of cheap tires (costing 12-14 usd / 8-10 eur) have no protection at all.

Puncture resistant tires are a bit more expensive (20 usd/16 eur), but unless you run over a spike strip used to stop cars, it should keep random punctures and flats away.

Last but not least are puncture proof tires. Their price ranges from 30usd to up to 60 usd (25 eur to 53 eur) with the more expensive ones have excellent manufacturer warranty aswell (Schwalbe Marathon Plus has 5000km and 3 year warranty on any prodction defects).

I have never seen a flat with Schwalbe Marathon Plus tires that could be classified as a puncture (I did see one tire that had been punctured on the sidewall by a metal rod. But the owner decided to repair the damage using kevlar thread and the tire is still in use today).

WD40 IS NOT LUBE

There is a huge misconception when it comes to WD40. It is a fantastic thing to use when something is seized or needs to be cleaned up (surface contamination). Also, it helps to remove grease/oil from metallic surfaces really well.

What WD40 is not, is a lube. When you spray it out, it dries out in a short while. Regular oil, grease does not do this. So when you spray a healthy amount of WD40 on your chain, it dries out in a day or two, removes all the oil that was there and causes surface rust to appear(unless you live in or near a desert). This causes a chain to wear out 10x faster.

If you spray WD40 on a chain to clean it, then let it dry, wipe the residue off and then add quality chain lube.

WD40 is a fantastic tool in your toolbox, but make sure to use it properly and in the right way.

Frame building basics #1 - common threads found on bicycles

 - Introduction

Bicycles that were built in the last 20-30 years have a set of common threads that are used for parts and accessories. While many manufacturers use common bottom bracket threads, children's bicycles and BMX bicycles have a different bottom bracket size and thread.

 - Bottom bracket (Please note that these threads are cut to 55 degrees (included angle)):

Imperial – 1-3/8-24 TPI . Meaning that the diameter of the thread is 1 inch and 3/8ths with a thread pitch of 24.

Metric – 34.80x1.05mm. Rarely used in metric standard, since all taps and dies are according to Imperial standard.

Please note I am not including French, Italian bottom bracket sizes as they are less common these days.

 - Accessory lugs (bottle cages etc):

 

Imperial – 3/16-24 TPI. Thread is 3/16ths in diameter with a thread pitch of 24.

Metric – M5x0.8. Thread is 5mm in diameter with a pitch of 0.8mm.

 - Rear derailleur hanger(that connects the derailleur to the hanger):

Imperial – none as far as I know(please email me if you have this info)

Metric – M10x1.0. Thread diameter is 10mm with a pitch of 1mm.

 - Rear hub axle threads (for cone nuts and locking nuts. While the sizes are similar, they are not interchangeable):

 

Imperial – 3/8-24 TPI.

Metric – M10x1.0.

 - Quick release sqewers:

 

Imperial – 3/16-24 TPI. Thread is 3/16ths in diameter with a thread pitch of 24.

Metric – M5x0.8. Thread is 5mm in diameter with a pitch of 0.8mm.

 - Thru-axle sizes (double check before buying replacements):

Metric: M12x1, M12x1.25 and M12x1.75mm. While the diameter is the same, the thread pitch is completely different (1mm is fine thread, 1.75mm is coarse thread and are NOT combatible).

 

Please note - all articles will be updated every few weeks with new and available information.