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AJ's Bikes Carbon Bicycle and Component Care
Drop by AJ's Bikes in Valrico, Florida and hold a carbon handlebar, seatpost or fork, or better, lift one of our full-carbon dream machines, and you'll be startled at how little they weigh. The real surprise, though, comes on rides, when the featherweight and beautiful miracle material transfers more of your effort to the ground, dazzling you with acceleration, climbing, control and even comfort, superior to anything you've pedaled before.
Carbon is so light and tough that Boeing picked it for their 787 "Dreamliner" jet. It's over 80% carbon, including the fuselage, which seats 300-plus passengers. And, perhaps the ultimate carbon creation ever, is the 197-foot-wide wing. With the Dreamliner's 360,000-pound takeoff weight and Mach 0.85 cruising speed, this amazing and gossamer carbon structure must withstand a lift force of some 450,000 pounds. Our top brands of Road Bikes and Mountain Bikes carry high-end carbon options, including Specialized and Giant.
Yet, even with incredible strength and toughness like this, with a single indiscriminate act like clamping your carbon wonder wrong in your repair stand, over torquing with an Allen wrench, or letting the handlebars swing around and smash into the top tube, you can do some serious damage.
It's possible because carbon has very different qualities than steel, aluminum and titanium, which you've probably ridden before. Unlike these metals, carbon is a synthetic composite material comprised of fibers soaked in epoxy resin and then compressed, heated and cured. Essentially, your carbon jewel is made up of a super-strong fabric, which requires a little new know-how on your part. The foremost being that while metal shows signs of damage, typically bends, dents or bulges, carbon may appear normal, yet, if compromised enough, even though you can't see the defect, the component could fail without warning. Another issue is notch sensitivity, which means that deep cuts, gouges or scratches can cause carbon to break and should be inspected by a pro immediately (and avoided!).
Now that we've got your attention, there's really no reason for concern as long as you treat your carbon gear correctly. To help, we asked our mechanics for their best tips, picked the brains of every industry carbon guru we know, and culled information from the major carbon bike and component leaders' websites to bring you this guide to caring for and maintaining your carbon bicycles and components.
Reading, understanding and following the guidelines, instructions and recommendations here will greatly increase the chances that you never have any problems. And, if you ever have a question or are unsure how to proceed, please contact the experts at AJ's Bikes first, and we'll be happy to help!
There's a lot to know about carbon and many insider tips and tricks. So, for easy navigation, we've organized our guide into sections covering the issues, and tips for the individual components of a bicycle, too — frame, fork, handlebars, seatposts, etc. Use the links below to quickly jump to any section. First, be sure to read the Basic Carbon Care section as it explains things pertinent to all carbon bicycles and components.
BASIC CARBON CARE
Get, Read, and Know your Owner's Manual
All carbon bicycles and components include either print owner's manuals or digital versions you can read and download on the company's website. Before doing any service on your bicycle or components, you must thoroughly read and understand the manual. This is where you'll find the proper torque settings, any special tools or techniques that are required, warranty specifics, contact information and more. We can answer and advise about the carbon products that we support, however, the only way to be certain that you have the most up-to-date and accurate information about your specific item is to own, read and understand its specific owner's manual.
Some simple steps can ensure that your carbon bicycle becomes an heirloom. One of the easiest is parking it safely. Never lean it in such a way that it can roll and fall on its side or slam into anything. For example, don't rest the seat or frame against a pole and think it's safe (no matter how gently you placed it there), because the bike might move letting the frame crash against the pole, which could easily damage it. Or, the handlebars might swing around all the way and smack into the top tube. To prevent these risks lay the bike down in a safe place when you park it or at least ensure that it's resting on a level surface and leaning against a wall. Also, some companies recommend avoiding exposing your bicycle and components to high temperatures such as leaving them inside a parked car in the sun or storing them next to heat sources or radiators. Similarly, if you live by an ocean where there's lots of salt in the air, or if you're a person who sweats excessively, you should take extra care to clean and rinse the salt off your bicycle and components to protect them from any possible corrosion of the metal parts.
If you crash or abuse your bike, or forget that it's on your roof rack and ram it into your garage, look for signs of damage, and have them checked out. Remember that damage may not be visible to the untrained eye. We're always happy to inspect and advise so bring it by the shop. And, do not ride until you're sure the bike/component is safe. Even if you never crash, you should frequently inspect your carbon bicycle and components for any gouges, deep scratches, cracks, loose fibers or other surface cracks and stop riding until you fix the problem.
When cleaning, if your rag snags on something, it could be a sign of damage. Also carefully listen for uncommon sounds when riding, such as creaking or cracking or popping, which could mean there's a problem. And, if you suddenly find that your bike isn't shifting or braking properly, or it's not handling the same, stop and check the bike carefully. Remember, we're always happy to help. Just bring your bike by the shop. Also, while you may have heard that carbon can't be repaired, it actually can in many cases. We recommend Calfee Design.
The mechanical clamping action of repair stands concentrates powerful loads in a small area so you should always clamp your carbon bicycle safely. Never clamp the frame. Instead, if you have a round aluminum seatpost, clamp that. If your seatpost is carbon, the safest thing to do is to purchase an inexpensive aluminum seatpost that's the same diameter as your post and then use it for clamping when you work on your bike. You can hold the bike by the carbon post if it's round and you clamp it gently, but you may scratch it unless you're very careful and the jaws of the repair stand clamp are safe (keep them clean of dirt and wrap a piece of wax paper around the seatpost to help prevent scratches). Visit the experts mechanics at AJ's Bikes for the latest in carbon repair tips.
Here's where we see a lot of problems. Avoid them and protect your machine by being sure to read and understand the owner's manual for your bicycle and components before doing any work. Even as seemingly straightforward an issue as whether or not to grease components depends on the manufacturer's recommendations. Some say to never grease, some call for it on certain parts, and some recommend special greases made for carbon components.
Over torquing is probably the biggest cause of cracks that we see in carbon products. And, it's much harder to determine the torque on a bolt by feel with carbon than it is with aluminum. The best way to avoid problems and do the job correctly is by getting a torque wrench and always using it and the company's torque chart when working on your bike. Here's some excellent information on proper tightening and torque specifications from our friends at Park Tool USA.
Another important step is to check parts during installation and assembly to ensure that there are no burs, rough spots, dirt or metal shards that could cut into and harm the carbon when the components are assembled and tightened. The surfaces must be smooth or you should smooth them with fine sandpaper or by cleaning.
You also need to work differently than you may be used to. For example, you may have gotten in the habit of putting a part on and then twisting it to see if it's tight and then tightening the bolt a little more if the part needs it. But, this is a recipe for disaster with carbon because by twisting/turning the part, you can cut into the carbon damaging it! With carbon you want to align parts once and then tighten completely. Or, if you need to fine-tune an adjustment, you should loosen fully, reset the part and tighten fully.
Another metal-bicycle technique that won't work on carbon is trying to change the frame spacing. It's set to accept modern wheels perfectly. Never try to stretch or compress your frame more than 2mm or you may damage the frame or dropouts (it's impossible to bend carbon frames). Also, it may seem obvious but we've seen just about everything and we'd like to emphasize that you should never drill holes in your frame for any reason, no matter how logical it may seem at the time. If you're planning on doing so please contact us first so we can listen and explain.
Tip: If you need to size your carbon handlebars (and the manual okays it), or cut your new fork to size, we recommend using a carbon-specific hacksaw blade. These blades essentially "sand" through the carbon instead of tearing through with teeth, which tend to fray and splinter the fibers in the composite. It’s also good practice to wrap the carbon with tape before cutting, though this is less necessary when using a carbon-specific blade.
Car racks that clamp to the frame tubes should not be used because of the enormous loads concentrated in a small area. Likewise, when using racks that clamp the fork, never pull sideways (and be careful not to lose your balance, which can cause this) when removing the bike because this can break the dropouts (fork tips). Always fully loosen the fork mount and then lift until the fork is clear of the mount before removing the bike. And with tall-section carbon wheels, you may need to use a different, longer strap. Use caution to protect the rim with pipe insulation or something that keeps the strap from compressing or chafing the rim as it gets jostled when you're driving.
It's fine to wash carbon bicycles and components like you would any other using warm soapy water and a hose. Yet, as with any bike, it's never a good idea to aim the water directly at bearings (headsets, cranks, etc) because that can wash the grease out. For especially greasy components any bike-safe degreaser, which we can supply, will work fine and won't effect the carbon in any way. After cleaning, rinsing and drying, we recommend adding a little protection with a bike polish or spray wax (Pledge furniture polish works nicely and you simply spray it on and wipe it off).
Stone dings, chips and scratches aren't usually anything to worry about in terms of strength and longevity. Most carbon bicycles feature clear-coat finishes, which are easy to touch up. All you need is a little clear nail polish or model paint and you can cover the spot to seal it and restore the finish. Another possible risk is throwing the chain during shifting, either onto the bottom bracket or off the large chainring. This won't damage anything as long as you stop pedaling right away, though we would recommend letting us check the shifting since a properly adjusted bicycle shouldn't toss the chain. Should the chain nick or chip the finish, simply clean the area and touch it up to protect it. Tip: to protect the bottom bracket area from dropped chains, you can put a strip of electrical tape on it.
Chain suck is mostly a mountain-bike glitch that results from worn, dry, muddy or damaged parts, and from bad shifting technique, too. What happens is the chain gets grabbed and "sucked" up, jamming between the chainring and chainstay. You can generate a lot of force with your legs and if you don't realize what's going on and you just keep pedaling, the chain can "saw" into the frame and damage it (even steel frames). So, if you experience chain suck on a ride, stop pedaling immediately, and avoid riding in the gears that are causing it. When you get home, clean or adjust or replace the faulty parts to prevent it from happening again. Or bring your bike in and let us diagnose and repair the problem for you. If you did pedal and mar your frame, we should also take a look and make sure it's okay.
Should your bike need repainting at some point, it must be done correctly and carefully. We recommend using a professional bicycle painter who understands carbon frames, such as Calfee Design. Caution must be used because any paint stripper that will remove polyurethane/urethane paint will also damage the epoxy resin matrix holding your carbon together. So do not use paint stripper. Also, you must not sandblast, beadblast or blast with any other media to remove the paint because that can remove structural material ruining the frameset. If you do decide to repaint, the correct approach is careful hand sanding to remove the decals and scuff the topcoat to receive the new finish. Finally, do not bake a carbon frame at over 150 degrees Fahrenheit (baking is often used in painting metal frames) as that will damage it, too.
CARE OF BICYCLES AND COMPONENTS
It's impossible to bend carbon frames, so never try to stretch or compress the frame to change the spacing. It's set to accept modern wheels perfectly and will only flex by about 2mm. By forcing it you can structurally damage the frame or dropouts. Also, it may seem obvious but we've seen just about everything and would like to emphasize that you should never drill holes in your frame for any reason, no matter how logical it may seem at the time. If you're planning on doing so please contact us first so we can listen and explain.
When installing bottom bracket cups do not use thread adhesives as this can secure them too tightly in the frame and cause damage to the threads when it's time to replace them. Instead, we recommend greasing the cups.
When cutting a new fork to size, we recommend using a carbon-specific hacksaw blade. These blades essentially "sand" through the carbon instead of tearing through with teeth, which tend to fray and splinter the fibers in the composite. It’s also good practice to wrap the carbon with tape before cutting, though this is less necessary when using a carbon-specific blade.
Of course, the old saying measure twice, cut once is never more appropriate than when sizing forks. Cutting a fork too short can completely ruin it, so be sure to read the manual to understand how to fit it and how to measure it according to the specific instructions for your type of fork. Keep in mind that the fork, headset, insert, spacers and stem act as a system so you need to consider all these things when sizing and installing a fork to get it right. If you're in doubt at all, letting us size and install the fork for you is strongly recommended and well worth the reasonable cost. When installed correctly the front end of your bicycle will be an integral part of your bike that fits the frame and you perfectly, and that requires only routine maintenance, too.
When installing a headset, grease the insides and faces of the head tube where the cups go in, as well as the crown race seat of the fork. Cups should be professionally installed by us with a headset press, a special tool for the job that maintains correct alignment of the head cups during assembly.
Carbon forks usually require special longer brake nuts that come with the forks. Standards brake nuts usually won't work, so be sure to get and use the correct one (they often come with new forks or we can sell you one).
Crashed or damaged frames and forks that show signs of damage, such as cracks, chips, loose fibers or fatigue marks, or those that you even suspect were damaged, should be taken out of use immediately and inspected by us or another qualified expert to ensure they're still safe. If evidence of damage is found, the components should be replaced or repaired.
Safety first! If your wheels have carbon rims be sure to get and use the specific type of brake pads recommended by the manufacturer. Also, use only plastic tire levers when fixing flats because metal ones can damage carbon rims unless you're careful.
Speaking of flats, you probably know not to ride on any flat tire, but on a carbon rim, it's even more important and could ruin the wheel, especially on a clincher carbon rim, which has tall sidewalls that could delaminate should they contact the pavement for very long. Of course, as with all wheels, be sure to check tire inflation before every ride. Failing to do this can lead to rim damage, as it would on an aluminum rim, should you hit a pothole or rock and bottom out the soft tire.
For sew-up (tubular) carbon wheels, on which you must glue the tires, be sure to prepare the rims by scuffing them lightly with steel wool to clean and slightly abrade them. Then glue the tires on. Keep in mind that, like any sew-up, if the tire remains on the rim too long, it can be difficult to remove, and on carbon wheels this can result in damage to the rim when you try to take the tire off and some carbon comes with it. If you know you're not going to ride your carbon wheels for a long time, such as over the winter, it's best to take the precaution of removing the tires so this can't happen.
Spokes can loosen on any wheel and should be checked regularly for optimum tension. Carbon wheels often have tall rims that are very stiff and this can make it difficult to tell that the spokes are loose because the wheel may barely go out of true. If you just keep riding, the spoke tension can go down to nearly nothing compromising the strength and ruining the ride. So, be sure to check tension regularly by squeezing the spokes, or if you're not sure, having us check it for you. A good practice is to have any wheel checked for tension at least yearly, or more if you ride a lot. It's a good idea to have the bearings inspected at the same time, too, and serviced as needed.
When securing a bicycle with carbon wheels on a car rack be sure not to use straps that can chafe and cut into the rim. With tall rims you may need to replace the stock strap with a longer one. Just be sure to pad the rim against damage.
One thing that won't harm carbon rims/wheels is hanging a bicycle from them on hooks for storage. They can easily support the weight of the bike.
Crashed or damaged wheels that show signs of damage, such as cracks, chips, loose fibers or fatigue marks, or those that you even suspect were damaged, should be taken out of use immediately and inspected by us or another qualified expert to ensure they're still safe. If evidence of damage is found, the components should be replaced or repaired.
Make certain that the diameter of the fork and stem, and the stem and handlebar match. And make sure that all surfaces are smooth and free of any defects, dirt, burs or sharp edges that could cause damage. Also make sure the components are free of oil, grease and grime. Tip: The one exception is that it's okay to put a small amount of grease on the handlebar center section, which will help the stem's clamping surface spread the force around the bar.
A common practice with metal handlebars and stems is to snug them up and then test to see if they're tight enough by tugging or twisting. Never do this with carbon bars and stems as twisting and tugging can turn the parts, scratching and/or scoring them leading to failure. Always align the components correctly first, then tighten fully to the recommend torque specification. And, if you need to change the adjustment, be sure to fully loosen and open the clamp before moving the part.
When mounting brake and shift levers, inspect them carefully, especially at the clamps to ensure that there are no burs or sharp edges that can cut into the carbon handlebars. As we mentioned with the bars themselves, be sure not to twist the levers to move them into place because that can score and cut the carbon causing failure. Always loosen the clamps fully, reposition the lever, align it carefully and then tighten it. Tip: You can also disassemble the lever clamp and slide it alone into place on the handlebars and then install the lever. To align drop-bar levers rest a straightedge against the bottom portion of the handlebar. The tip of the brake lever should just touch the straightedge, or you can move the lever up as much as 10mm if you like a higher lever position.
Tip: If you need to size your carbon handlebars (and the manual okays it), we recommend using a carbon-specific hacksaw blade. These blades essentially "sand" through the carbon instead of tearing through with teeth, which tend to fray and splinter the fibers in the composite. It’s also good practice to wrap the carbon with tape before cutting, though this is less necessary when using a carbon-specific blade.
Bar-ends and Aero Clip-ons
The owner's manual with your handlebar will say whether it is compatible with bar-ends or aero clip-on handlebars. If it is, be sure to then select bar-ends or clip-ons designed for carbon handlebars. One important precaution is to never use anything that uses a clamp with a slot that's not in line with the handlebar hole/clamp and a bolt which isn't perpendicular to the slot. This arrangement causes the clamp to close unevenly driving one edge into the handlebar, which will crack it. You can test for this by eyeballing the slot and the bolt. An imaginary line should exactly bisect the clamp and slot. If you're not sure, place your finger inside the clamp and snug the bolt feeling for any deformation of the clamp as it closes. It must remain completely round as it's tightened in order to be safe.
Crashed or damaged handlebars and stems that show signs of damage, such as cracks, chips, loose fibers or fatigue marks, or those that you even suspect were damaged, should be taken out of use immediately and inspected by us or another qualified expert to ensure they're still safe. If evidence of damage is found, the components should be replaced or repaired.
Do not use regular grease on any carbon seatposts or carbon seat tubes. Tip: There is a new carbon grease we can supply that includes small particles so it protects and grips, however, unless you have this special product, you shouldn't use any grease.
Make certain that the diameter of the frame and the seatpost match. And make sure that the surface of the frame's seat tube is smooth and free of any defects, dirt, burs or sharp edges, especially at the clamp, which could damage the seatpost. Also make sure it's free of oil, grease and grime.
When inserting seatposts, always insert them just enough to achieve your proper seat height. Putting them too low and then having to raise them could result in scratching and damaging them.
Tip: Never put a scratch in a carbon seatpost to mark it, either! Doing so can ruin the seatpost and cause it to break. Instead mark your seat height by wrapping a piece of electrical tape around it right at the frame.
Before tightening seatposts, pay particular attention to the orientation of the seat collar. When using a carbon post, it’s very important to have the seat collar slot on the opposite side of the seat tube slot. This helps disperse the loads better, reducing the possibility of pinching and crushing the seatpost, as well as reducing frame damage. Diagonally slotted seat collars are highly recommended.
When tightening, never overtighten the seatpost clamp on the frame or you can ruin the seatpost and even damage the frame. First, check your owner's manual for the frame or clamp, follow the instructions, and tighten the seatpost to the required specifications with your torque wrench.
Crashed or damaged seatposts that show signs of damage, such as cracks, chips, loose fibers or fatigue marks, or those that you even suspect were damaged, should be taken out of use immediately and inspected by us or another qualified expert to ensure they're still safe. If evidence of damage is found, the component should be replaced or repaired.
When installing pedals check carefully that there are no burs or defects on the pedal axle seats (the areas that rest against the crankarms) that could cut, gouge or scratch the crankarms during installation. Also, never install washers between the pedals and the arms as this can increase stress on the crankarms.
Be certain to check your front derailleur regularly. It's possible to catch your pants in it and bend it, or you might try to fine-tune it and change its motion slightly. Either of these things could endanger your crankarm by allowing the front derailleur cage to move too far to the outside when you've shifted onto your large chainring. When this is the case, the derailleur cage may gently brush against the inside of the right crankarm with each pedal revolution. You might not even feel or hear this, yet with only a few rides, this could lead to serious damage to your carbon crankarm.
Though it's unlikely to do any serious crankarm damage, use care when walking your bicycle up curbs and over similar obstacles, too. If a crankarm is at 6 o'clock, you could strike the end of the arm against the cement and mar it.
A common shifting/drivetrain glitch on mountain bikes, and even sometimes on road bikes is called "chain suck." It results from worn, dry, muddy or damaged parts, and from bad shifting technique, too. What happens is the chain gets grabbed and "sucked" up, jamming between the chainring and chainstay. You can generate a lot of force with your legs and if you don't realize what's going on and you just keep pedaling, the chain can saw into the frame and damage it (even steel frames). If you experience chain suck on a ride, stop pedaling immediately, and avoid riding in the gears that are causing it. When you get home, clean or adjust or replace the faulty parts to prevent it from happening again. Or bring your bike in and let us diagnose and repair the problem for you. If you did pedal and mar your frame, we should also take a look and make sure it's okay.
When installing bottom brackets, we recommend greasing the threads and following the manufacturer's recommended torque setting. Caution: do not use thread adhesives (Loctite) on the bottom bracket threads! Loctited cups require additional torque to remove, which may exceed the torque limit on the frame's bottom bracket and damage it.
As with all other components, crashed or damaged crankarms that show signs of damage, such as cracks, chips, loose fibers or fatigue marks, or crankarms that you even suspect were damaged, should be taken out of use immediately and inspected by us or another qualified expert to ensure they're still safe. If evidence of damage is found, the crankarm should be replaced.
We would like to thank these companies for help with this article (in alphabetical order): Bontrager, Calfee Design, Campagnolo, Easton, FSA, Hed Cycling Products, Kestrel, Orbea, Park Tool, Reynolds Composites, Shimano, Specialized and Trek.