WHAT CAUSES A CREEK?
Today’s bikes, as advanced as they may be, still seem to be able to creak just as bad and as often as those from many years ago. Sure, we may have cutting edge suspension, nearly maintenance free disc brakes and enough carbon components to make an F1 car jealous, but our state of the art machines will often have the most curious noises emanating from who knows where. How can this be? And what causes these god awful sounds that can make us want to abandon our expensive bikes in the bush and walk home?
Those noises, often referred to as a “creak”, are usually the result of two components shifting under load against each other. While it can sometimes be as simple as the seat post within the frame or the handlebar and stem clamp, it is more common to have the noise be a result of two threaded components not being properly torqued down to the manufacturer’s spec, allowing them to shift ever so slightly when you push hard on the pedals or lean into a turn. The tricky bit is that the part doesn’t actually have be loose to make the noise – the actual movement may be exceedingly small – which can mean that it may be difficult to track down. Add in a bit of dust, grime or water to the joint between the two and you’ll have the perfect environment to make what will quickly become the world’s most annoying sound.
|You may need to use a number of different tools in order to track down and remove that pesky noise, but a torque wrench and some grease will help you the most.|
Safety warning: The good news is that creaks are often not a major issue, but rather just your bike telling you that it’s time to take a day off from riding and give it some love. The bad news is that that isn’t always the case, with the noise sometimes signalling that you have a cracked frame or a part that is close to complete failure. This is why it is important to not let those creaks and groans go unnoticed for long. Not to scare you, but that sound could quite literally be a warning that your head tube is about to depart from the rest of your bike, or that your lightweight two piece crankset is close to becoming a three piece unit. Spending a few minutes tracking down the sound may just save you from having to search for your front teeth mid-ride, or at the very least a long walk of shame out of the bush with your broken steed on your back.
Finding the cause: The two most important weapons in fighting the war against noise are grease and knowing the proper torque, but often the most difficult part is tracking it down – it usually isn’t as easy as just listening to where the noise is coming from. Mountain bikes, especially those that are built around an aluminum frame, are really good at helping the sound to resonate from its origin. It may sure as hell sound like that tick is coming from your rear wheel, but don’t be surprised when you find that your stem was the source all along. While a creak can come from pretty much anywhere that a component is clamped or threaded into another part, including a front derailleur band or even a water bottle cage bolt, there are a few common offenders. For this reason it helps to know a some tricks on how to isolate the noise and make it easier to find…
Some helpful pointers before you begin:
• Proper torque is key to eliminating creaks and groans. Check out Park Tool’s page on torque specs, and be sure to find out what your components require.
• Depending on the component, you may need to use grease, lube or Loc-tite to stop a noise. It is important to not only use the right one, but to also wipe away any extra that may be present after reinstallation. It will only attract grime and cause even more noise.
• Tools you may need include a hex set, torx wrench, bottom bracket tool and a torque wrench, among others.
|Bottom bracket, crankarms and pedals: These are the most common offenders of them all. Head out onto a quiet side street and pedal hard against your brakes while standing up (standing will eliminate your saddle and post). You don’t have to go fast, it’s the torque from your legs that will cause noise, not how fast you’re going. Listen carefully for the noise during the hard downstroke of each pedal revolution – that is when it will be most likely to occur. Found the culprit? Start by crossing out the easiest causes first. Remove your pedals and give the threads on both the arms and on the spindles a cleaning, applying a dab of grease to each before reinstalling. Head out for another ride to see if the noise is still there, and if it is the next step is to remove the crankarms and bottom bracket from the frame. Spend a few minutes cleaning everything so that it looks as good as new – using a solvent will help. Be sure to read the manufacturer’s instructions before reinstalling the components, and also lay on a coating of grease to the crank spindle, as well as the threads on both the BB shell and BB cup. Remember that torquing each part to the recommended amount is key to eliminating noise.
Often one of the trickiest to spot, chainring bolts can make quite a racket when slightly loose. Aluminum chainring bolts are even more prone to noise. If you’ve done all the steps above, but still have a noise when standing and pedalling under load, it may be the these little guys. Remove one at a time, cleaning and putting a small dab of grease on the threads before reinstalling. Never use Loc-tite on chainring bolts – it isn’t needed and will make life difficult down the road.
|Spokes and nipples: When you hear a mechanic say that the “wheel has lost its tension” he is referring to the spokes becoming looser than is ideal, allowing the wheel to flex more under load. This is also likely to allow the spokes and nipples to shift slightly, even if they don’t feel loose to the touch, and it’s this shifting that can cause noise. Before re-tensioning wheel, something that should only be done by someone who has experience working with wheels, drip a small amount of lube into the nipple hole at the rim, as well as at the hub and where the spokes cross. A wax based lube will dry and leave a residue that will last much longer than a teflon based lube. Be careful not to let any drip onto your brake rotor.|
|Saddle and post: If you suspect that the noise may be coming from your saddle clamp or the post into the frame, pedal hard under load (dragging the brakes can help) while seated and then while standing. If the creak disappears when you are out of the saddle there is a good chance that it is one of the above. Begin by marking or measuring your saddle height before removing the post, followed by a good cleaning of the inside of the seat tube (including under the seat post clamp) and the post itself. Reinstall after applying a thin coating of grease or non-slip compound to the inside of the seat tube, post and under the seat post clamp. It also makes sense to remove the saddle from the post and clean the clamping surfaces as well.|
|Rear suspension: A coil spring that doesn’t have enough preload applied to it, letting it shift on the spring clip and collar, will also be prone to making noise. This is a good place to start, much easier than removing and greasing pivot bolts, if you push down on your bike’s rear suspension and it makes a groan. Simply grab the coil with your hand and see if it is loose enough to shift on the shock. If so, give the collar half a turn and retry. Repeat until it no longer moves, but keep in mind that coils springs should only have a few turns of preload on them. A small amount of lube between each end of the spring and the collars can also help, but be sure to wipe any extra away so as not to attract dirt.
Pivot hardware can also make quite a bit of noise, although this is one that can be intimidating for the home mechanic, requiring the removal of the pivot axles and bolts, applying grease (as well as Loc-tite if required) and retightening to the exact specs provided by the manufacturer. While I would love to cover that in this Workshop Wednesday it would make for a rather long read. If you don’t feel up to it take it to your local shop and have them perform the service. It will be money well spent.
Derailleur pulley wheels: These little guys will often make a high pitched chirp that will sound as if a bird is following you on the trail. You’ll know if they are the culprit if the intervals between the chirps are quick and happen with consistant timing while you pedal. Remove one at a time, giving it a good clean before reinstalling. Most pulleys actually use a bushing that, while designed to run dry, will benefit from a very small amount of teflon based lube. If your’s use a sealed bearing you can use a hobby knife to lift the edge of the seal up to remove it and allow you to lube the bearing. Apply a small amount of blue Loc-tite to the threads on the derailleur cage to prevent the pulley bolt from coming loose down the road, but be careful to not let it run down onto or into the pulley wheel itself.
Ride better through knowledge….
Bike Mechanic / Fleet Manager
0800 444 144 / 09 257 4673