Shutting Up the Cranks|
Wednesday, May 30, 2007
No one wants to baby their mountain bike out on the trails -- you gotta stay aggressive if you want your riding to improve.
But what's that creaky sound you keep hearing whenever you pedal? That's the sound of all the mucky water and choice dirt you've been tearing up, back to haunt your bike. Most likely, it's the bottom bracket and crank area that are gummed up.
Here's how to silence the creaks and keep your cranks turning smoothly. After all, there's nothing wrong with babying your bike when you're back at home.
1) Get a torque wrench, and fit it on your crank bolts. Use the gauge on the wrench to check how tight the bolts are. Tighten the bolts to manufacturers' specifications, then do the same to your chainring bolts.
2) Give 'er a pedal. If you still hear squeaking, check the bearings by grabbing the crankarms and moving them back and forth. If they can move sideways at all (which they're not suppposed to do) the bearings are worn out.
If there's no movement, slide the chain off the rings, spin the cranks and listen for a rumbling noise. At the same time, put a hand on the frame to feel for any vibration. Rumbles or vibes point to worn-out bearings you'll need to replace.
3) Most bottom brackets are replaced as a unit, so replace both bearings at once. The units are also sold with the tools to do the job. Keep your old, worn-out parts on a necklace to show how awesomely handy you are.
4) Test it out again. If you still hear a noise, remove the cups on the bearings, clean the threads, grease everything up and put the cups back. Make sure to use quality waterproof grease on aluminum surfaces, and anti-seize stuff on titanium. (If you ride in wet conditions a lot, you should do this 3-4 times a year.)
5) When you're putting the crankarms back together, always grease the bolt threads. Do NOT grease the spindle on an old-school, square-taper bottom bracket. Clean it with alcohol and put it in dry. Torque it to spec with your torque wrench.
6) If you still hear creaking after doing all this, you may want to invest in some earplugs.