DIY Bike Maintenance

To wrap up Bike Month, we consulted master bike mechanic and owner of Velofix, Guenther Anger, on the basic bike maintenance every cyclist should know. Keep your wheels spinning smoothly with these tips for basic repairs, adjustments, and bike cleaning, as well as recommendations for when it’s best to turn to a professional mechanic.

From needle-nose pliers to Torx wrenches, the number of bike-related tools can be overwhelming. Luckily, you can complete the vast majority of DIY repairs with just a few basics. Here’s what every cyclist should have in their saddlebag:

• A good multi-tool. This should have 15-17 tools, including an Allen wrench set (2- 8 mm in size) and both flathead and Phillips screwdrivers
• Spare tube
• Set of tire levers
• A pair of rubber gloves (to spare your hands from chain grease)
• A hand pump

Of course, other tools may be necessary depending on the kind of maintenance you’re comfortable doing.

Refer back to this diagram if you’re unsure which part of the bike we’re talking about! Note that this is a mountain bike. Other kinds of bikes (such as road bikes and hybrid bikes) will look different.

Usually, a dropped chain is a quick and easy fix. You may be able to pop the chain back on while pedaling slowly and shifting the front derailleur up or down (depending on which direction the chain fell). If you’re already off the bike, try clicking the shifter and then lift up the back tire and use your hands to “pedal.” If you’re lucky, the chain will pop back on and you’ll be good to go.

Still no luck? Put on a pair of rubber gloves to keep your hands from getting greasy. Create more space by pushing the rear derailleur forward. This will add slack to the chain. Use your hands to place the chain back on the front chain ring. Pick up the back tire and give the bike a quick pedal, shifting if necessary.

If your chain is dropping on a regular basis, you’re either making your bike cranky by shifting poorly, or it’s time to get your bike looked at by a mechanic.

Follow these steps to fix a routine flat and avoid some common mistakes.

1. Take off the tire. To make removing and replacing the wheel easier, shift down to the smallest cog in the rear wheel and the smallest cog on the crankset in the front. Open up the brake pads. Pop open the quick release and take the wheel out.

2. Find the culprit. Check the entire outside of the tire for damage, removing any tacks, glass, or other debris wedged into the tire. This will also help prevent further flats!

Next, take off the damaged tube. Hook the rounded end of one tire lever under the bead (the outer edge) of the tire. Hook the other end onto a spoke to hold the lever in place. Scoop the second tire lever under the bead next to the first one and run it all the way around so that one side of the tire is hanging off the rim. Remove the tube.

Meticulously inspect the tube and the inside of the tire for damage, running your fingers around the tire’s entire circumference. To pinpoint where the puncture occurred, it may help to pump up the old tube while listening and feeling to find where air is escaping. Then line up the tube with the tire and examine that section more closely.

3. Put in a new tube. Inflate a new tube until it holds shape. This will ensure that the tube doesn’t get caught between the rim and the tire as you install it, which would lead to a pinch flat when you pump up the tire.

4. Reinstall the wheel. Install the valve and work the tire back onto the rim with your hands, rolling the bead away from yourself. Pump up the tire to the correct pressure and reinstall the wheel. As you tighten the quick-release lever, keep the bike on the ground to help the wheel sit straight. Close the brakes again and check to give the wheel a spin to make sure the brake pads aren’t rubbing.

Note: Unless your tire has been slashed through, ripped, or otherwise significantly damaged, you will not need to replace the tire itself (just the tube). If you are having repeated flat tires, have a mechanic check your tires and the rim of the wheel.

Replacing your brake pads when they’re worn down helps keep you safe and while keeping your rim in good condition.

Open up the brakes, loosen the bolts on the brake pads, and take them off. Make sure to remember how the pads and spacers were originally situated—you’ll want to duplicate this when you install the new pads.

Check the direction of the brake pads before installing. An arrow usually points which way the pads need to face, and the curve of the brake follows the curve of the tire. Put on the new pads and gently tighten the bolts with your hands. Once both brake pads are on, line up the pads on the rim so that they’re even. Center the pads on the rim so that they are neither too high and touching the tire nor coming off the bottom of the rim. This prevents damage to the tire and uneven wear on the brakes.

Hold the brake pads in place, apply the brakes and tighten the bolts. To avoid squealing brakes, toe the brakes inwards slightly by slipping a business card between the back end of the brake and the rim of the wheel as you tighten them into place.

The drive-train is comprised of all of the components that “push” the bike along, including the chain, chain ring, cassette, pulleys, and derailleur. Keeping these components clean and lubricated is an easy way to keep your bike happy, healthy, and riding smoothly. It will prolong the life of your bike’s components and save you money in the long run.

There’s no need to get special degreasers for this; regular dish soap like Dial works great. Mix some soap with water and use a sponge or a cloth to wash off the chain and components, rotating the chain to get off as much grease as you can. You can even use an old toothbrush to get into the smaller spaces. If you’re feeling ambitious, take off the rear wheel to clean the cassette more easily. Hose down the drive-train and dry it with a rag.

Apply lubricant to the chain and pedal through the different gears to spread the lubricant around, then wipe off any excess lube. Note that oils that are specifically marketed as bicycle-chain lubricants are superior to non-bicycle-specific products (such as WD-40), as they generally contain Teflon and are designed to repel dirt and water.

Know the correct tire pressure for your wheels and keep them filled—the recommended pressure is typically printed on the side of the tire. Underinflated tires can lead to inefficient riding and flat tires when the tube gets pinched between the tire and the sharp edge of the rim. Overinflated tires can cause a harsh ride, flats, and poor traction on bumpy surfaces.

Guenther recommends checking tire pressure and pumping them up before every ride. Don’t be alarmed if the pressure seems high! The skinnier the tire, the higher the pressure: usually, road bike tires take 100-120 PSI (pounds per square inch), hybrids take 70-85, and mountain bikes take 40-50. As a rule of thumb, a correctly inflated tire will have a slight bulge where it makes contact with the road while the rider is seated. Over time, you may also come to know if your tires need to be pumped by squeezing them for approximate pressure.

Knowing how to remove pedals and put them back is helpful if you travel with your bike. To take off your pedals, you’ll need either a 15 mm pedal wrench (for most pedals), or an 8 mm Allen key that you’ll insert behind the pedal.

Protect yourself from potential injury by placing your chain onto the big ring. Turn the crank arm to the 3 o’clock position, and align the wrench with the crank arm. Use your foot to generate more leverage as you push the wrench down, loosening the pedal.

A quick tip to remember which way to loosen the pedals: think about how you ride. The direction that you pedal is the direction that will tighten the pedals; the direction of “backpedaling” will loosen the pedals. This means that the right side pedal follows the “lefty loosey righty tighty” rule, but the left side pedal is reverse threaded.

If your pedals haven’t been removed in a while, you may want to spray a little penetrating fluid, such as GT85, to loosen things up. Keep spraying fluid every few turns until the pedals are free. This will help prevent damage on dry and corroded threads.

If your bike hesitates in shifting up and down between the gears in the back (the cassette), you can make a simple adjustment by playing with the cable tension. This fix works for the majority of rear shifting problems. However, if you have a damaged derailleur (the part that moves the chain between different cogs), a bent derailleur hanger (the “fish hook”-shaped part that connects the derailleur to the rest of the bike), or are unable to do a simple fix, you’ll need to take your bike in for service.

To adjust the derailleur, find the round, knob-like piece where the cable enters the derailleur. This is the barrel adjuster, which is used to adjust the rear derailleur. Standing behind the bike, turn the barrel adjuster in half-turn increments until the problem is solved. Test the shifting between each adjustment.

The direction you’ll need to turn depends on the type of shifting problem you’re having. Most often, the bike stalls when shifting into easier gears due to the cable stretching.

To know which way to turn the barrel adjuster, remember this rule: if the shifting hesitates when moving into an easier gear (when the derailleur moves toward the spokes), tighten the cable by turning the barrel adjuster towards the spokes (counter-clockwise). If the shifting hesitates while moving into a harder gear (away from the spokes), give the cable more slack by turning the barrel adjuster away from the spokes (clockwise). You’ll know you’ve hit the sweet spot when you can shift up and down easily, with one gear shift per click.

In some cases, tinkering with your bike can do more harm than good. Here are some examples of when it’s best to shell out for a professional fix:

Truing wheels. A sign that your wheel needs truing is if it appears to “wobble” back and forth as it spins, hitting the brake pads. Expected cost to fix: $15-$25 in labor.

Replacing cables. Fraying, broken, or rusted cables will prevent you from being able to shift and brake safely. You may also need to replace the housing (the tubing around the cable). Expected cost to fix: $6-8 per cable + $10-$20 in labor.

Replacing or changing a chain. Replacing your chain as it “stretches” will save you from replacing other, more expensive components. As the chain wears down, it starts to mesh poorly with the cogs and chain-rings. This leads to poor shifting and “skipping” over the cogs. Expected cost to fix: cost of chain (variable) + $10-15 in labor.

Derailleur and shifting problems. Take your bike to a mechanic when you’re not able to fine-tune the shifting by using the barrel adjuster or tightening the cable. This may mean the derailleur hanger is bent. Expected cost to fix: cost of parts (around $20 for a derailleur hanger, $45+ for a new derailleur) + $10-$15 in labor for an adjustment, $20 for a replacement.

Guenther fell in love with biking while racing BMX on local tracks around New Hampshire. His passion later grew to riding and repairing mountain and road bikes. With the verification of a BSE Level 2 Certification from the Barnett Bicycle Institute, Guenther is now the owner and master mechanic of Velofix. He has 20 years of keeping cyclists in and around Boston safe in the saddle.

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