Trailside Bike Repair Fix Guide
Common Mid-Ride Bike Fixes
Have you ever been out on the trail – maybe far out from the trailhead – when CLUNK, BANG, SQUEAK! Sometimes mechanicals can happen at the worst time and place, even when you’re out on the trail.
Often, you can avoid trailside bike issues in the first place by maintaining your bike between rides. By completing a pre-ride safety check, and bringing your bike into the shop for regular maintenance, you can prevent many issues like:
- Smashing your rim on a rock because you forgot to check your tire pressure before the ride!
- Ruining your brake rotors because you let your brake pads wear down to the metal!
- Destroying your spokes, derailleur or worse… yourself… because you haven’t done a bolt check in a while!
Still, accidents can happen during your ride. So, it’s always best to be prepared for any mishap – especially when you’re on a long ride far from home.
What to Carry on Your MTB Ride
First thing’s first, you need the right tools and supplies. Here’s just a sample of the items you might want to bring with you to be prepared on your next ride:
- First Aid Kit
- Extra gloves and socks
- Phone and charger
Spare Parts and Tools
- Fix-a-Flat Kit (C02, valve, tube, tire levers, pump)
- Tire Boot (the wrapper from your trail snack will work!)
- Tire Plugs
- Quick links for your chain
- Duct tape
- Zip ties
- A GOOD multi-tool*
*Multi-tools: Not all multi-tools are created equal. Some just don’t have all the tools you need. Check your tool before you head out on your next ride. Does it have a chain tool? If it doesn’t, it would be a good idea to bring a separate chain tool, or get a new multi. A broken chain is a pretty common mid-ride issue and even if you have a spare quick link, you won’t be able to use it until you remove the gnarled chain bits. For more on fixing broken chains, check out our guide here! In addition, check to make sure your multi has other common tools you use, such as a T25, screwdriver, rotor truing tool, etc. A knife also comes in handy!
Now that you’re prepared, let’s fix some common trailside bike issues.
Bent Brake Rotor
If you happen to have a crash or you just lay your bike over on a rock the wrong way, you could possibly bend a brake rotor. Sometimes, this isn’t a huge issue... you can make it home with an annoying squeak in your front or rear wheel every time you pedal. Other times, the bend can be so bad it can actually inhibit your wheel from moving. If you’re far out, that extra pedaling effort can add up. Here’s the fix:
- Flip your bike over to give yourself the best view of your brake rotor and the caliper.
- Be careful! Don’t touch the brake rotor right away. If you’ve been riding on a trail with a lot of braking, the brake rotor could be hot. Also, the edges of the brake rotor could be sharp.
- Spin the wheel.
- Looking at the caliper, notice where the wheel stops moving/ where the rotor hits the brake pad.
- Using a multi-tool with a brake rotor truing tool* attachment, place the tool on the brake rotor in the location of the bend.
*If you do not have a rotor truing tool, you can use your hands to bend the rotor. Keep your gloves on. This method will not be as effective or precise.
- Bend the rotor in the opposite direction of where the rotor is hitting the brake pad.
- Keep spinning the wheel and making small adjustments until the rotor is straight enough to spin freely and allow you to pedal home.
Broken Shifter Cable
Usually, there is a sign that your derailleur cable is starting to fray at the bolt before it breaks all the way. However, sometimes a sharp rock or abrupt shift can be enough to snap the cable. If you’re super prepared and carry a spare derailleur cable with you, you can replace the cable trailside. If you don’t have a spare, you’ll need to improvise; otherwise, you’ll be stuck in the hardest gear – which would make it hard to pedal home. Here’s the fix:
- Using a zip tie, secure the dangling cable and housing to your frame so it is out-of-the-way of any moving parts.
- Look for the limit screws on your derailleur. These screws should be marked with an “L” or an “H” and will require either a screwdriver or small Allen wrench to move.
- Using the H, or high limit screw, tighten until chain moves into an easier gear.
- Be careful not to overtighten this bolt! Tightening the limit screw should move the derailleur in and you can achieve 3-4 shifts using this method.
- Pedal forward and make sure the chain isn’t skipping.
- Use micro turns on the H limit screw to perfect the alignment for smooth shifting.*
*Learn more about derailleur adjustments and limit screws by checking out our guide here!
Broken Derailleur Hanger
Your derailleur hanger is the small piece of metal that connects your frame to your derailleur. This bike part is made of soft aluminum on purpose – so your derailleur hanger will bend or break BEFORE your derailleur. The thing is, derailleur hangers are cheap and derailleurs are not… so always keep a spare on hand! Remember, hangers are specific to certain bikes – so make sure you have the right one.
If your derailleur hanger does break or bends and starts causing shifting issues, the best fix is to replace the hanger. Here’s how to do it:
- Shift into the smallest gear in the rear and pedal forward.
- Flip your bike over. This will put your bike in the most stable position for changing your derailleur hanger.
- Remove your wheel.
- Remove the derailleur. There is one bolt that connects your derailleur to the hanger. It will generally require a T25 or 5mm Allen wrench. Once your derailleur is removed, make sure you do not put the threads of the bolt in the dirt which could cause friction when the derailleur is replaced.
- Remove the bent hanger. Usually, there is another bolt (or two) that hold the derailleur hanger onto the frame. Retain these bolts when the bent hanger is removed.
- Place your new hanger on the bike. Do not overtighten derailleur hanger bolts, small bolts usually require low torque.
- Replace the derailleur. Check the torque specifications on the derailleur (usually listed right by the bolt). The bolt that secures the derailleur to the hanger usually has a high torque specification, meaning you should really put your arm into it when tightening this bolt!
- Replace your wheel.
- Pedal forward and shift up a few gears to check the derailleur alignment and ensure shifting is smooth.
- Backpedal to ensure the chain is not bent (this can sometimes happen if the derailleur hanger bends significantly or breaks). If your chain is bent, remove the affected section of chain. Learn more here!
You have tubeless tires now, so punctures on your mountain bike are a thing of the past… right? Sure, you will have far fewer flats now that you have tubeless, but punctures are still possible. Holes in your tire that are too big for your sealant to fill will cause you to lose air. Depending on the size of the hole, you can use a tire plug to fix the problem. Plugs are quick and easy to use and always something good to have on hand. If you have a tear in the sidewall of your tire that a plug cannot fill, you might need another method of patching it. Here’s how:
- Prepare your fix-a-flat supplies and tube. Learn more about how to fix a basic flat here.
- What can you use to patch a hole or tear in your tire? A dollar bill, a nutrition wrapper, or a tire boot can do the trick.
- Change the tire like normal, but as you add the tube into the tire, place the boot over the hole you want to cover.
- Replace the bead of the tire, pump it up, and roll on home!