When asked, “What kind of bike do you ride?” most of us will quickly utter the name that appears on our bike frame. Though every bike is made up of a collection of parts from several manufacturers, the frame builder usually gets credit for making the bike what it is. – By Todd Downs
This is not entirely incorrect, as the details of each frame’s construction determine how the bike will behave more than any other single component. So what maintenance should you perform to ensure the long life of your bike’s frame? A lot more than you might think.
Besides bike accidents, the greatest enemy a steel frame may face is corrosion. You needn’t worry about this much if you ride an aluminum, carbonfibre, or titanium frame. But if yours is steel (if you’re not sure, check it with a magnet), take care. If you sweat a lot on your bike while you ride, either indoors or out, thoroughly rinse it off as frequently as is practical. Salt deposits form in any kind of corner, especially underneath clamps, and continue the process of corrosion, even if the bike is dry. Braze-on parts contribute less to this severe problem than clamp-on parts, but they still trap unwanted salt. (Salt can affect aluminum, carbon fiber, and multi-material frames and components, too.)
Clear silicone-rubber bathroom caulk can help keep sweat and water out of the inside of your bike’s frame. Unless the locknut on your headset has an O-ring seal, sweat can seep down the sides of your stem into the steerer tube. The resulting corrosion can sometimes require the use of a hacksaw to remove the stem from the steerer. A thin bead of clear caulk around the base of the bike stem (wipe away the excess) will prevent the problem.
While the best defense against corrosion is to prevent moisture from entering your frame tubes, it is also a good idea to help fight corrosion from the inside. Anytime you have your seat post out of a metal frame or your headset or bottom bracket dismantled for an overhaul, use the opportunity to spray or swab a rust inhibitor such as WD-40 inside the exposed tubes.
Obviously, the best way to help your frame last is to avoid twisting it out of shape in an accident. A good bike frame has considerable resilience but cannot be expected to regain its original shape after being wrapped around a tree. If you’re unlucky enough to crash and bend your frame or fork, take it to a mechanic for evaluation. A shop with alignment tools can sometimes straighten metal frames and rigid (non-suspension) forks enough that they still ride fine.
Metal dropouts in carbon fiber frames may be fixable, but only by experts. Under no circumstances should you try to align the frame or fork itself. Bent suspension forks can often be repaired by replacing the damaged parts.
Paint chips can allow rust to start even on a dry, salt-free steel frame. To prepare the surface for touch-up paint, don’t sand the chipped area except to remove rust. Most manufacturers treat their frames’ bare surfaces with a very thin phosphate coating that inhibits rust; sanding will remove it.
Instead of sanding, use a solvent, such as lacquer thinner, to clean any oil from the chipped area. Then cover the chip with one or more coats of almost any type of paint that matches your bike’s original color. If rust has already reared its ugly head through the hole in your frame’s finish, use fine sandpaper to remove all of it before you touch up the frame. Don’t expect miracles: The main purpose of your touch-up work is to minimise rust damage to your frame until you have it professionally repainted.
There are some other steps worth taking to protect the paint on your frame. Because the bike chain is close to the right rear chainstay, it can slap against it when you hit bumps. This makes a metallic clanking sound and can lead to chipping paint on the chainstay. A simple way to protect the stay and muffle the chain slap is to put a vinyl or foam chainstay protector over the stay. These are adhesive-backed and cost only a couple of dollars at your local bike shop.
Another good way to protect paint is to stick tape beneath cables where they rub the frame, such as shifter cables that strike the frame by the head tube. This will prevent them from wearing a hole in the paint. Just cut a small oval of tape (get clear tape or tape the same color as your frame so it’s not noticeable) and stick it on under the housing.
To stop the rattling and resultant paint scratches you might get from bare cable sections (such as the rear brake cable under the top tube), install cable O-rings. Shops should have these. These tiny rubber doughnut-shaped O-rings slip over the cable and prevent it from vibrating when you’re riding.
Sometimes a crash dents a frame tube. Though unsightly, these dents rarely weaken the frame much. If you can’t stand looking at a dent and you have a steel frame, you can have a frame-builder fill the dent with brazing material. After painting over it, for all practical purposes your frame will be as good as new.
Again, for carbonfibre frames, any sign of surface damage could mean a crack and failure. Have your frame professionally examined. There are many carbonfibre builders who can repair carbonfibre frames.