Trailside Repair: The perfect bike tool kit

Breakdowns and defects on the trail happen from time to time - for some, they are rare, while others seem to be unlucky. But just in case, it's always good to know how to handle them.

With a few tips and some tools, you can fix the most common issues in the woods and get back on your bike quickly. This way, you'll also be well prepared to offer help to other bikers.

Tools and Spare Parts for Your Mountain Bike

Tech nerds get almost as much fun from good tools as from the latest bike parts. But even if you’re not tech-savvy, it’s worth having a small selection of thoughtful and quality tools for the road. You can easily pack the essentials in a backpack or hip bag – or have them readily available on the bike. There are saddle bags and frame bags, holders, and integrated solutions. It’s important that in the rush and confusion of a breakdown, you know where to find the necessary tools.

We’ve divided our suggestions into three levels:

Basic Gear – The essential items you should always carry to make it back home on your bike.

• Minitool / Multitool – This handy gadget combines the most important tools. There are numerous versions available. Ideally, you have the right tool for every screw on your bike (Torx and hex keys).
• Pump – A small hand pump or one with CO2 cartridges is essential for fixing flat tires.
• Tire levers – If your multitool doesn’t already include them, tire levers are recommended. They weigh next to nothing and can be a big help in removing stubborn tires.
• Tubeless repair kit – There are various types, but all serve the same purpose: to plug holes in the tire. This is usually even faster than changing a tube – of course, only if you’re running tubeless.
• Spare tube – Whether tubeless or not: if a patch won’t hold, a spare tube will.
• “Classic” patch kit – If the spare tube gets a puncture, the classic patch kit with vulcanizing fluid or self-adhesive patches will save the day. If you're riding with TPU (Thermoplastic Polyurethane) tubes, check the manufacturer's recommendations.
• Chain link – A chain link weighs next to nothing and is invaluable if your chain or a buddy's breaks. Make sure it’s compatible with the chain (number of gears)!
• Chain tool – To fix a broken chain, a chain tool may be needed. Many multitools include one – otherwise, there are compact versions available separately.

For the long haul – When you're on a very long trip, like multi-day bikepacking, it’s sensible to also cover maintenance and wear to some extent.

• Chain lube – Many manufacturers offer their lubricants (oil or wax) in small bottles for travel. Check out our Toniq lubricants in practical refill packs.
• Spoke wrench – With a spoke key, you can true your wheels or replace broken spokes.
• Spare spoke – To replace broken spokes; consider different lengths for rear, front, left, and right if necessary.
• Brake pads – Wear can sometimes occur faster than expected – e.g., in muddy conditions. Don’t forget the appropriate retaining pin (screw or cotter) for the brake pads.
• Shift cable – Replacement for snapped cables.
• Selection of screws – Screws sometimes come loose unnoticed and get lost. Having spares is valuable. How many and which screws you carry as backup is very individual – they should match your bike. First think of safety-related connections like brakes, brake discs, and the stem, but also the pedal cleat, if you use clipless pedals.
• Second spare tube – Because a puncture can always happen again.
• Cassette tool – To tighten a loose cassette.
• Tubeless sealant – About one “portion” – if you lose a lot of sealant through a tire puncture, you can refill with some reserve.
• Charger for electronic components – Plus the appropriate cables to charge with a power bank or at a socket.
• Local knowledge – When planning tours or a vacation, it's sensible to keep track of when and where you'll pass by workshops – in case you need help or a major replacement part during a breakdown. By the way, we ship worldwide and to parcel lockers.

The classic: flat tire

You've just cleared the infamous rock field at the end of the trail when you hear a short hiss and realize that your bike feels somewhat squishy on the ground. One of the sharp rocks has probably punctured your tire down to the rim, creating one or even two holes – no reason to panic though. If you're running tubeless, you'll quickly see where the tubeless sealant is leaking out. With a bit of luck, the damage is small enough that the sealant will seal it as you spin the wheel a few times. Then, all you need to do is pump back the air you lost and off you go. If that doesn't work, it's time to reach for the tubeless repair kit. With the small, sticky strips of fabric and rubber (often referred to as "worms" or "bacon strips" due to their appearance) and a tool that resembles an undersized pitchfork, you can directly plug the holes in the tire. After that, pump it back up to your ideal air pressure and carry on.

Sealant and tire repair kits are not only for punctures (snake bites) but also for piercings and cuts – as long as they're not too large. Tire punctures have become significantly less common with tubeless setups and in most cases are also much easier and quicker to repair. If that doesn't do the trick or if you're still riding with inner tubes, then you're left with the good old spare tube or patching the tube. For that, you can use a vulcanizing patch kit or self-adhesive patches. To ensure the tube holds air and doesn't immediately go flat again, make sure to check the tire for foreign objects (thorns, nails, shards, etc.) and remove them.

Then there's the slow leak: You notice air loss, but air isn't visibly, tangibly, or audibly escaping from the tire anywhere. This has driven many bikers mad. Our tip: Take a closer look at the valve. Is it tight and securely screwed onto the rim? Is the valve core tight and closed? If you haven't checked and replaced the tubeless sealant in a while, it could be that it has dried up and the tire is losing air through the smallest porous openings. If you're riding with an inner tube, it could be that a thorn has caused a tiny hole or that it has become porous. In case of doubt, a spare tube will also help here.

Fixing Gear Issues on the Trail

Click, click, click – You shifted, but the chain just clatters and rattles annoyingly without moving to the next sprocket. Often, this is quickly and easily fixed by adjusting the cable tension on the shifter. If the chain doesn't shift up to a larger sprocket, turn the adjustment screw (the knurled screw where the shift cable exits the lever) a bit in the direction of travel (outwards) and try shifting again. A quarter or half turn is often enough. If it doesn't shift down to a smaller sprocket, then you should turn in the opposite direction.

Other possible causes for shifting problems could be a loose derailleur or cassette. You can easily check if the derailleur is securely screwed to the frame's hanger with your multitool. To check the cassette, carefully grab the largest sprocket (possibly with a cloth) and see if it wobbles relative to the hub. If that's the case, you definitely need to tighten it.

After a crash, the derailleur hanger on your frame might be bent. This too leads to erratic shifting. A quick look from behind at the derailleur gives you an instant impression. The derailleur cage should stand vertically – parallel to the rear wheel. Be careful not to be confused by the spokes – they are angled and not vertical. If something is bent, you can try to carefully (!) bend it back. It won't be perfect, so be really careful. Afterwards, you can adjust the shifting as described above focusing on the gears in the middle of the cassette, and avoid the very large and small sprockets on the way home. At the next opportunity, you should replace the derailleur hanger and – if it's also damaged – the derailleur itself.

Disc Brake Issues

Modern, hydraulic MTB disc brakes are reliable and almost maintenance-free. Still, problems can occur along the way, some of which are easy to fix:

• Brake disc constantly rubbing: If your brake is permanently rubbing on one side, then realigning the brake caliper so that the disc sits precisely in the middle between the brake pads can help. Simply loosen the two screws that mount the brake caliper to the adapter, frame, or fork a bit. It's enough if the brake can move to the right and left. Now, hold the corresponding brake lever and screw the brake caliper back tight. Usually, that's all it takes. One reason for rubbing brake pads could be that the brake pistons are more sluggish on one side than the other. You can see this if you closely observe the pads, activate the brake, and one side moves less than the other. Then, find out from your brake's manufacturer how you can mobilize the pistons again.

• Bent brake disc: If the brake pads are not rubbing evenly but only at a specific point during a rotation of your wheels, then your disc is probably bent. This might happen, for example, after a crash. It's best to turn your bike upside down to more closely inspect the discs while slowly rotating the wheel. Remember the spot where the disc rubs and gently bend it in the opposite direction. To grasp it, you can use pliers. Alternatively, an adjustable wrench works too. Some multitools have a slot that's specifically meant for this purpose. Make sure no grease or oil gets on the disc. When bending the disc, proceed in small steps and repeatedly check if it rotates freely through the brake pads. Often a slight correction is enough.

• Worn brake pads: As soon as you suspect your brake pads might be worn (brake lever travels closer to the handlebar, metallic noises, and reduced braking power, etc.), you should take a closer look and replace them if in doubt. How exactly this is done varies from brake to brake. In almost all cases, you should consider two things: 1. Pushing back the pistons: This is best done while the old pads are still in. 2. The correct orientation of the new pads: Make sure to install the pads in the right direction and secure them correctly (with a locking screw or a pin).

If one of your brakes still doesn't have a pressure point or fails to deliver braking power for other reasons after considering our tips, you should abort your ride. You might be able to roll home carefully and slowly with one brake. In case of doubt, however, it's better to push, use public transport, or get picked up. The risk of an accident is not worth it.

Preventing and Avoiding Breakdowns

On the trail, there are situations where you just have bad luck, and then there are those you can actively prevent. If you regularly maintain your bike, you'll encounter problems less often. Loose or even lost screws can be avoided by regularly checking at home if everything is tight. The same goes for play in bearings, e.g., in the headset. If you notice worn brake pads in the workshop, you won't need to change them on the go.

Another advantage of a well-maintained and cared-for bike: If you do have a breakdown on the way, the repair will be easier and cleaner. If you regularly look after your MTB at home, it will also be more familiar to you, and breakdowns are less likely to unsettle you.

We've got inspiration and tips ready for you in two articles on the blog: How To: Inspecting Your Bicycle and Bike Care - How to Clean Your Bike.