Velo 21 has teamed up with Target Composites Ltd to bring you this article for us that own carbon bikes! To learn more about Target Carbon Composites Ltd check out their website at www.targetcomposites.co.uk they offer all kinds of Carbon fiber repairs. Click here for more info! Also head over to their Facebook page here to see some of their work!
The lightweight, corrosion-resistant nature of carbon fibre, along with its incredible strength, has made it the perfect material for bike frame design. In its raw form, carbon fibre is malleable and can be moulded into an endless variety of forms, but once hardened it becomes incredibly strong. Concerns over its fragility are misplaced. Carbon fibre parts are considered so strong that they are universally used by both the aerospace and automotive industries. In fact, it is one of the main materials used in Formula One, a highly dangerous and tested automotive area.
Tip 1 – Buy a torque wrench
Although incredibly resistant to forces in the direction it is designed for, crushing can easily damage carbon fibre. Over-tightening of clamps and bolts, such as around handlebars and seat posts, is one of the most common causes of carbon fibre damage and failure in bikes. All components on a carbon fibre bike will have recommended torque values given in newton metres (Nm) that will either be marked on the relevant component, available in the supplied manual, or on the manufacturer’s website. A torque wrench ensures that you don’t tighten beyond these values, and should be considered essential if you own a carbon fibre bike. If you have only previously owned metal framed bikes, you’ll probably be surprised how little force is required. (You can purchase one from Wiggle here – LifeLine Essential Torque Wrench)
Tip 2 – Take care clamping to bike racks and stands
Carbon fibre is designed to be incredibly strong under riding forces. The compressional stress put on frames when clamped in a bike stand, or put on a car rack, are completely different though. Frames with hard edges in their design, such as Canyon and Cervelo, are particularly susceptible to clamp damage as the force is concentrated on the edge. Never force a clamp shut on your frame, it’s much better to hold your bike in the stand by the seat post if possible.
Tip 3 – Use assembly paste.
Apply carbon interface grease at contact points such as stem clamps and seat posts. Galvanic corrosion can occur at points where carbon fibre meets aluminium or steel (titanium is an exception). (Like this one from Wiggle Morgan Blue Carbon Assembly Paste.).
Tip 4 – Dry It Down
Store your bike somewhere dry, and keep well away from water, especially salt water! Water acts as an electrolyte in a chemical reaction, increase the amount of water and you speed up the reaction. Salt is a chemical accelerant in this reaction and therefore speeds things up even more. Also, if you’re using your bike on a turbo trainer then it’s a good idea to put a towel across the handlebars to catch your salty sweat. Velo 21 have a fantastic drying towel in our range with 1000GSM it is perfect for ensuring your bike is dry and protected! It can be found here!
Tip 5 – Reinforce and Protect
Protect any contact points on the frame from movement abrasion which can occur easily in areas such as around mudguards or race numbers that are zip tied in place. Applying electrical tape or a scrap piece of inner tube is ideal for this.
Most bikes come with a chain suck plate to protect the frame from occasions when the chain gets jammed between the chain stay and ring. We hate this so much that we supply frames that come to us without a suck plate with one of our own carbon Kevlar armour plates. This is the same material used in Armed Forces style anti-stab vests, so it stands up extremely well against bike chains.
Stone Chips and Scrapes
Fitting your frame with a Heli tape kit gives your bike a protective skin to against stone chips and other scrapes. It does an amazing job of maintaining your bikes value when it’s time to sell it on. Peel the Heli tape away and your well ridden bike looks brand new again. (Like this from Tweeks Cycles 3M Leading Edge (Helicopter) Frame & Component Protection Tape 1m x 10cm £14.65).
Tip 6 – Test and Monitor
There are 4 simple tests you can conduct yourself with the same level of accuracy, these are:
- Situational evidence
Learning what happened to the bike and gathering evidence about the situation is an obvious one. If the bike has been in a crash and taken a direct side impact then the chances of damage are obviously greater than if the bike hasn’t been in an incident but a hairline crack has appeared.
If the suspected fracture is on a seat stay for example, you can knock a coin against the tube and note the sound it makes. First, tap the edge of a coin gently on an undamaged area of the seat stay and note the sound, then tap the coin against the area of suspected damage and see if there is any difference. A damaged tube will sound dull because the sound waves are escaping through the fracture instead of resonating without obstruction.
Lightly press your thumb against the damaged area and see if it flexes any more than further up the tube at an undamaged section. If there is movement there you might also hear a creaking noise as the fracture flexes. Hairline cracks can be a tricky one. Quite often it is purely paint damage but it can also indicate a manufacturing fault in the carbon lay-up. If a creaking noise can also be heard then it is worth investigating a little further.
Sometimes a crack or fracture can appear without any apparent reason, and this may be the result of a manufacturing fault that has weakened over time. If the carbon cloth becomes creased when pressed into the mould during manufacture, then the strength of that section is weakened significantly as the fibres are no longer running how they should. This is a lot easier to see in a naked carbon finish as the fibres will appear bunched up around the area where the hairline crack is. It’s not so easy to diagnose this with a painted frame. The best option is to mark both ends with a permanent marker or record the length. Every time you take the bike out for a ride check the marks to see if the crack has grown over time. If it does then stop riding the bike and look into getting it fixed.