We need to physically inspect the bike and use our specialist test equipment on the damaged area using non-destructive testing methods including ultrasound to confirm the extent of damage and provide a firm quote. It’s best to bring in your frame for a physical assessment, assess the right course of action to take, and accurately quote.
Impact events, crashes, or damage caused in transit from crushing forces often result in damage that is more extensive than it appears in photographs. The physical assessment helps us custom design the repair & refinishing solution for your bike and ensure that it’s safe to repair. Our repairs are backed by a comprehensive warranty.
* Standard quote inspections are free if you go ahead with a repair, otherwise a $120 fee is chargeable to cover our time and use of specialised test equipment.
** Full component ultrasound scan may be limited by part design and geometry. Inspection requires parts to be stripped down, which can be done by us at an additional cost.
We use ultrasound technology to inspect and assess frames and parts to understand and check the uniformity of the laminate thickness of the carbon structure. We can then map out damaged/delaminated areas or find defects such as - the presence of voids and/or porosity, wrinkles or seams, inclusions, and foreign material presence or quality and bonding of the laminate and integrity of previous repairs.
Due to the lower safety coefficients of the latest frames (super lightweight), the need for damage-detection and characterization has increased. Hidden internal flaws and defects within a carbon frame are not uncommon. These hidden flaws and defects might result from manufacturing anomalies, applied stresses or weaknesses, accidents, or improper repairs. They can have a significant impact on the structural integrity of the bike and are normally not detectable by radiography (X-Ray) or by NDT techniques other than Ultrasonic Testing (UT).
Knowing this information influences the repair strategy or allows us to write a Damage Assessment Report.
Ultrasonic Testing (UT) is well suited to carbon frames and components as, one-sided access is sufficient, minimal or no surface preparation is needed (do not need to remove paint). UT is highly accurate in determining the exact point of a hidden anomaly and its main characteristics such as depth, size, and shape. UT provides instantaneous results and objective data.
Some bike brands, distributors, or shops may ask you to remove some paint to see if the carbon is cracked underneath and not just the paint. This is because they cannot tell if the carbon is damaged, an underlying manufacturing defect or if in fact, it is just a paint crack/ scratch. This is not a good process and will only reveal the surface layer as well as causing cosmetic damage.
Ultrasonic testing with the correct equipment and a well trained and experienced operator is a powerful and non-invasive method of testing a carbon frame or component. Carbon Bike Doctor has invested extensively in the right equipment and experience to bring this aerospace industry-accepted testing method to the bike industry.
The traditional coin-tap testing is one of the oldest methods of non-destructive testing and it is regularly used for testing laminated structures. Acoustic/ Percussion testing requires the surveyor to tap each point of the structure to be inspected with a coin and listen to the resulting sound radiated by the structure.
Unfortunately, the coin tapping method is dependent upon the inspector’s hearing and interpretation, the results are subject to interference from background noise, and this technique is unable to provide quantitative data.
Composites are widely used in the aerospace industry. One of the biggest players in that industry - Boeing. They have developed an Electronic Digital Tap Hammer that provides a quantitative measure of the hammer/composite impulse time that can be correlated to flaws such as delaminations in the structure. The instrumented tap hammer supplements the tonal discrimination of the operator with a numeric readout that is related to local part quality. The effects of background noise and operator differences on the inspection results are eliminated. This hammer is relatively insensitive to the magnitude or forcefulness of the hammer hit, but very sensitive to the local stiffness of the structure. This method provides objectivity in the test, increases the sensitivity of the test and enables the inspector to collect quantitative results of the actual impact response.
At Carbon Bike Doctor we have invested in this equipment and use this technology to test your frame. The Electronic Digital Tap Hammer has proven to be a powerful and non-invasive method of testing a carbon frame or component as the readings can be correlated to corresponding parts of the frame and give quick numeric readings for comparison.
Taking into account the customer provided details of the circumstances of the incident resulting in the damage, a visual inspection is conducted using some or all of the following equipment – high intensity spot lamps, fibrescopes for internal inspection of tubes, magnifying glasses, penetrative solvents and use of a cotton gloved hand sweeping over the surface to feel for fractured carbon fibre ends.
The bike frame has been designed to be strong in the directions needed to take the loads under normal riding conditions. Carbon fibre can be designed to have directional strength or even flex if so desired. The frame would be much heavier if it was designed to have strength in all directions and be able to take loads outside of normal use. When a bike is crashed or crushed the frame is receiving forces that it was not designed to take.
Many of the latest model frames are designed to be as light as possible and have refined the manufacturing techniques so there is no excess material. Essentially durability has been sacrificed for lighter weight. Repair of damage and testing for damage is more important than ever.
As carbon fibre is made from many different layers an understanding of how the loads are received by the material and how it reacts to different loads is critical when assessing damage or bike frame.
Carbon fibre has the greatest strength in tension. Conversely, carbon fibre will fail in compression before there is a fail in tension. Often this can be on the inside of a tube and is the greatest contributor to ‘hidden damage’, i.e. no external signs of failure.
Under tension carbon fibre is very strong – tensile loads are carried by the long carbon fibres – like a rope.
Compressive loading of the carbon fibre the adhesive and stiffness properties of the resin system are crucial, as it is the role of the resin to maintain the fibres as straight columns and to prevent them from buckling. This why repairing the bike frame with the same Pre-preg / thermoset resin system is crucial as the resin is an important part of the material’s mechanical properties. Wet layup resins are not what the bike is made from so the bike should not be repaired in this method.
As loading carbon fibre in compression relies heavily on the resin and the resin is not as strong as the carbon fibre the material is more likely to fail in compression. When assessing a frame or damage it is important to understand the direction of the forces applied and how the material reacts. This is the reason we ask how your bike got damaged or what happened in the incident.
The below image shows a composite experiencing a shear load. This load is trying to slide adjacent layers of fibres over each other. Under shear loads the resin plays the major role, transferring the stresses across the composite. For the composite to perform well under shear loads the resin element must not only exhibit good mechanical properties but must also have high adhesion to the reinforcement fibre. The interlaminar shear strength (ILSS) of a composite is often used to indicate this property in a multi-layer composite (‘laminate’).
Flexural loads are really a combination of tensile, compression and shear loads. When loaded as shown, the upper layers are put into compression, the lower layers into tension and the central portion of the laminate experiences shear loading.
When a carbon fibre tube or plate flexes there are shearing forces between the layers of carbon fibres. The resin plays an import role here. Pre-preg / thermoset resins = GOOD; wet resin layup = NOT AS GOOD.
All repaired within 3 days-great job thanks so much!
Stephen Smith, Customer
Amazing workmanship, short turnaround, great value. Highly recommended.
Brett Hosking, Customer
Tristan repaired a crack in the frame of my Bianchi and the paint job he did over the repair is identical to what was there before. I cant even tell where the crack was as its done so immaculately.
Clive Burcham, Customer
Tristan is an artisan!!!
Clive Burcham, Customer
Tristan recently did some work on two of my swingarms and has repaired them to the point that I can’t find the damage… Seriously can’t pick it and his knowledge in this line of work is second to none. I definitely wont be taking my bike anywhere else. Not to mention the pricing even made the wife happy and the turn around was excellent…Bonus. Thanks again
Billy Lawson, Customer
What a great Company, very happy with all aspects of fixing my Cervelo R5.
Andrew Homann, Customer
Resurrected my 1st gen Scott Addict R2. Beautiful work!