Just for a moment would you to consider what the difference is (other than the obvious shape and function) between a bicycle frame and a wheel? The wheel is under tension and the frame is not until sat on. This means that the wheel receives a double dose of stress when it is over loaded when it impacts something.

There are two major types of wheel braking systems we will cover:

Rim brake and disk brake. Suffice to say that at last the bike industry as broken clean away from the traditional bike and into the future in this regard. The disk brake wheel is free of a few important problems: mainly the total incompatibility of carbon rim brakes.

You might ask the question ‘how so if race cars use carbon brakes’ well then you need to look closer and you will note that there has never been a carbon wheel with a drum brake system nor a laminated carbon disk to my knowledge and for very good reason – abrasion and heat warpage. The very two by-products when stopping a wheel. Both these by-products score very low indeed in carbon form for which designers have some work arounds.

We can look at these in a bit

For now let us look at the disk wheel and the pitfalls associated with carbon:

Carbon repairers cannot offer to stress test a fracture repair to destruction. That in itself is obvious. It is why we use robotics to replicate the mould. There are therefore only a limited amount of repair locations which are safe to undertake. Unfortunately the industry is still obsessed it seems with clincher/ tubules rims in carbon. Why do I dislike them? Very simply because they are still an artefact of the alloy wheel era. They have no place on a carbon wheel. It is my opinion that the whole wheel tyre system needs to be reviewed seriously as disk braking is a great leap forward so let’s finish the job!

For a start we do not repair clincher walls if they are cracked through. Why? The carbon rim bead must be able to hold the wheel bead when the tyre is under side load. If this wall flexes open through a crack the tyre bead can slip off and the rest I will leave to your imagination. We simply do not know what the specified load is to ensure it is safe to restore. The better news is there are many other locations on the wheel, which get damaged that we can repair.

This ranges from flat tyre abrasion of the rim edge provided there is no crack though the wall. We can advise. This we inspect very carefully. The other repair locations are most of the side wall of the rim body and cowling all the way to the spoke. Unfortunately if the spoke has ‘pulled through’ we will not repair these either. Again there is no way to know how successful the repair is under additional load. A failure of a repaired spoke hole can bring the wheel into collapse without much warning. Not good and certainly not worth the cost or the risk so please stay away from repairers who claim this is repairable, it is not

Candy paint is a mid-coat option. It’s always applied over your preferred base colour. The best options are essentially a clear coat with tinting, including pearl or metallic additives, that offer translucence to the Bikes frame. It is more vibrant which changes at different angles, creating a more ‘3D’ effect.

Before applying candy paint, you must place a base coat on the bike first. If you don’t take that step, you’ll see the primer through the base colour. That ruins the desired effect.

The coats need to lay evenly and look the same to ensure everything looks cohesive. If there are inconsistencies in the spraying techniques, you will be able to see the abrupt changes in the end result.

Metallic paint is the most common finish you’ll find on bicycles, even for custom looks.

Metallic paints use powdered metal in the product to reflect additional light than what you receive from a standard glossy product. You can also get more color depth and sparkle when using this option.

Metallic paint first started with fine flakes, but it has become more diversified as the size and shape of the additions change. Since the metallic bits float in the paint while it’s applied, it’s essential to use a product that maintains the product flow well.

The challenge with metallic paint is trying to color match. If you’re doing the custom work yourself, it helps to place each item next to each other to avoid slight development differences.

It is important to note manufacturers do NOT recommend clamping onto the frame

Most top tubes are not designed for clamping forces, while other top tubes are not round making it difficult to clamp safely. Also, when clamping the frame, it is possible to damage the paint, or dent / crush the frame tubing, especially if you have a carbon frame or lightweight alloy frame.

The frame tubing is much thinner, compared to the thicker tubing of a seat post, which is designed to support the weight and forces of the rider. All bicycles, including mountain bikes, should be clamped into your repair-stand either by the seat post or bike drop outs

If we look at the development of carbon bike steerers since carbon forks were implemented into carbon bike frames, steerers used to be mild steel or alloy which was welded into the brake arch to lead down each side of the blade into a generous lug which accepted the carbon blades and the alloy dropouts to finish off the design.

These were heavy and also the bonding of the two materials caused alarming paint crack lines over time. However weight reduction and manufacture cost was the reason designs started to look at the challenge of a safe carbon crown race. Some models employed a rolled up steerer tube bonded into an alloy brake arch which partially saved some weight. Then the evolution converted the brake arch to a one piece with integrated carbon blades including a bonded in-roll of carbon tube to secure the base of the crown race.

All designers steered away from a complete one piece design until manufacture techniques advanced enough for some rather scary designs with big voids and air pockets. But to counter this they threw carbon at the problem which again made them relatively heavy still and the forks were quite chunky. Slowly over time they were able to exit air bladders out of the steerer for both fork blades to create the 1st true monocoque.

On the outset let me say for the record that carbon steerers as a concept are not dangerous. I am simply saying that these components are not necessarily best designed for carbon. As are dropouts, chainrings, BB’s, rim brakes, clinchers, carbon spokes, h/bars and stems, saddle rails or any parts which do not warn you that they are about to fail or indeed show you that they have!

So with that out of the way let us get on with referencing the title with some context – The steerer has probably the most important function on the whole bike. Why? Because there is only one of, meaning that if it were to fail there are no other parts associated which can save you should it fail. I refer in particular to the fork crown race. The further up the steerer you go the ‘safer.’

Did you know that the steerer is supposed to be the front suspension of the bike? Yes it is. In fact one of the reasons modern head tubes are fatter than vintage bikes is so the steerer can flex freely between the upper and lower bearings. Remember it is well known that the steel bike, without this frontal flex design, was just fine and rode very smoothly due to the properties of steel. Carbon is a very harsh ride compared to steel and therefore I assume this was a consideration in the evolution of the carbon bike.

There are also secondary functions designed into the steerer which you did not know, and this varies from brand to brand and even model to model, and that is its role in frontal impact failure.

In a frontal impact or other trauma such as potholes or heavy frontal braking or sudden direction change, the steerer should survive only to keep the front wheel from collapsing. Remember what I said earlier that the steerer is a one of part which did not go un-noticed by the designers, you would hope! In many trauma cases we have reviewed it is very clear that by far the best outcome of a frontal trauma failure is the implosion of the downtube/ head tube junction before the steerer fails. In some cases the design for failure is to break just below the upper bearing race which, although you loose steering, will allow enough give to absorb an impact without fracturing the head tube. It is my opinion that the former is a more popular design at the cost of the frame but not your jaw line.

So you understand, just like the seat tube is quite a complex design consideration which most are not aware of.

Congratulations if you did as it certainly is not obvious!

We always advise that you regularly take the handlebar off and inspect it for any visible damage. When you are changing cables plus bar tape would be a convenient time.

Have your bike inspected is your best bet

However as a precaution – if your bike has been impacted or you hear a cracking sound after an incident it is important that they are fully inspected to ensure no fractures can hide within these depressions.

Low Modulus carbon fibres are recognised as the most common and cost effective fibres to produce, these are less stiff but strong once laid up with epoxy and cured. Whereas High Modulus carbon fibres will produce a part which is much stiffer, but not quite as strong.

How High Modulus Carbon Fibre is produced?

Carbon fibres start from some sort of polymer – which is essentially just a long chain of carbon atoms with other elements, such as hydrogen and oxygen, poking off the sides. The polymer is then heat-treated at very high temperatures.

This process removes all of those oxygen and hydrogen atoms and what you’re left with are the carbon atoms which have a very good bond strength

It’s this heat-treating process that determines whether a carbon fibre is high modulus or low modulus. The higher the temperature and the longer you heat treat it, will make the fibre even more pure and have a better carbon crystalline structure. This gives the carbon a higher modulus but with the temperatures and lengthy heat treating process, it’s also more costly.

When talking about carbon frames, it’s never actually pure carbon – it is a composite material, with resins to bond the carbon fibres together.

Manufacturers might use more standard and intermediate [i.e. lower modulus] fibres in high strength areas of the frame, giving the most optimised stiffness, strength and weight in the final product.

So a wide range of high modulus, intermediate modulus fibres and sometimes standard modulus fibres are used in all carbon bikes, and it’s all about putting the high stiffness and high strength fibres where they’re needed most. We usually see a combination of different carbon fibres that are used in most high-end branded frames because they are trying to optimise those characteristics of strength and stiffness.

It is never a simple subject but hopefully you can understand a bit more when someone tries to bamboozel you with jargon!

There is a lot of misinformation regarding winter damage to carbon frames. whether it is winter or summer you still need to keep your bike clean. If you leave ingress on your bike after a wet ride then that can eventually cause problems. It is not only specific to winter

Granted grit is only used in the cold months but as long as you are sweating over your frame on the turbo you are doing the same as you would on a winter ride. Wash it down and remove the salts. Salt eat at the cable stops and gets under the lacquer on spots where the lacquer is compromised. The good news is it can not penetrate the carbon itself

So ride the bike you love through the winter and into the warmer months. Well maintained carbon bikes are fine in all weather.

There are thousands of variations colours, tints, flakes and lacquers. Now with more than ten years’ experience with all the combination of paint finishes we are confident to match your frame colour.

Making it even more difficult, your bikes paint is like skin. Although you might not notice it until you see it from another angle, paint ages a little bit each day. Over time this adds up, the older your bike is the harder it gets to colour match.

Colour Match within 100% accuracy

To be able to colour match as many bikes to 100% , our relationship with the paint manufacturer has to be aligned to ensure our extensive services to the brands continue. This allows us to deliver near perfect finishes every time.

With bikes exposed to UV, We use scanning and recording process’s to register the variations in a large physical and data library.

There are literally thousands of brand colours in various states of exposure accessible at a press of a button to ensure matches are processed in a timely manner.

Please contact Carbon Bike Repair if you would like to explore a colour change or a restoration of your bike.