Mountain Bike Repair on the Trail

How to Perform Basic Trailside Bicycle Repairs

© Helen Smeaton

May 30, 2009
Mountain Bike Multi Tool, Helen Smeaton
A basic understanding of bicycle mechanics and the carrying of appropriate spare bike parts and tools is key for performing mountain bike trailside repairs.

Modern mountain bikes are robust and with proper servicing will give years of trouble-free riding. Out on the trail, however, things can still go wrong and it is impossible to carry all the necessary tools to solve every potential problem.

Some issues will render the bike unrideable, others less useable or less safe to ride, whilst many problems can be easily fixed. An appreciation of the most likely scenarios and how to fix them is therefore useful.

Bicycle Punctures

Punctures are the most common problem on the trail and are easy to fix. It is possible to repair the tube on the trailside but a simpler option is to carry a spare inner tube, a set of tyre levers and a pump to re-inflate the tyre. Whilst carrying a small puncture repair kit as an alternative will save weight and bulk, inner tubes can split and a patch may not be big enough to repair the damage so carrying a spare tube is a must.

Damaged Mountain Bike Tyres

It is not sensible to carry a spare tyre as they rarely disintegrate on the trail. They can, however, get torn or ripped leaving the inner tube exposed and more likely to be punctured. A lightweight, cheap and simple solution is to carry a small flat piece of flexible plastic cut from a margarine tub which can be put on the inside of the tyre wall adjacent to the tear, protecting the inner tube.

Bicycle Chain Break

Chains are incredibly strong but can sometimes break. Spare chains are heavy to carry so a better option is to carry a chain tool. This small lightweight device allows a rider to remove the damaged link from the chain and then reconnect the two undamaged ends to form a continuous loop. The chain will be shorter after the repair and gear shifting may not be as efficient but the bike will be rideable.

Mountain Bike Wheel Damage

Modern wheels are robust and, with proper maintenance, should not fail on the trail. If, however, a rider crashes or hits a large obstacle in the track the wheel can become buckled. It is possible to straighten or “true” the wheel by tightening or loosening spokes and a spoke key is an essential tool for this option. A spoke can also be replaced if it snaps so carry a spare.

Rear Derailleur Damage

The rear derailleur on most mountain bikes is a very exposed component. A fall can result in the bending or even snapping of the mounting bracket (the mech hanger) onto which the gear shifting mechanism attaches. The bracket can be bent back into shape but take care with fragile aluminium components.

Replaceable mech hangers are small and lightweight and can be carried in the rider's pack. The hangers are bolted to the frame using a hexagonal bolt and the only tool required is the correct sized hexagonal wrench. If the gear hanger cannot be replaced, just turn the bike into a single speed to get home.

Bicycle Brake Pad Wear

Occasionally a brake pad will disintegrate to the extent that it is unusable. A cyclist should carry a spare set of pads and have the knowledge to change the pads on their own bike.

Brake or Gear Cable Failure

Cables can fray and break on the trail. The bike will still be rideable with a broken cable but will be less useable or safe. It is therefore sensible to carry spare cables.

Loose Bike Parts

Some components can work loose on the trail. Crank arms, handlebars, stems, chain rings and saddles are all held to the bike by hexagonal bolts. A mountain biker is well advised to carry a small tool kit with the appropriate size hexagonal wrenches to tighten the bolts on any component which has worked loose.

Suggested Trailside Toolkit and Spares

Whilst tools and spares add weight to any bike pack, it is better to be prepared than face a long walk home. Riders should carry the following as a minimum:

  • Spare inner tubes
  • Tire levers
  • Pump
  • Puncture repair kit
  • Flexible plastic tire wall protection card
  • Brake and/or gear cables
  • Brake Pads
  • Gear hanger
  • Spoke Key*
  • Chain Tool*
  • Hexagonal Wrenches*
  • Pliers*
  • Knife*
  • Zip ties - invaluable for securing all sorts of broken parts.
  • Duct tape - the essential stick-all/hold-it-all-together item which even sticks broken shoes together!

*A good quality compact multi-tool will have all these items and more.

If all else fails, improvise using rocks, pieces of wood, or anything suitable found on the trail.

Trailside Bicycle Repairs

Be prepared by carrying the right tools and spares and learn basic bike maintenance skills to easily cope with mountain bike repair on the trail. Walking is a last resort option but the one to take if the bike is unsafe to ride.


The copyright of the article Mountain Bike Repair on the Trail in Mountain Biking is owned by Helen Smeaton. Permission to republish Mountain Bike Repair on the Trail in print or online must be granted by the author in writing.


Mountain Bike Multi Tool, Helen Smeaton
Bicycle Pump, Helen Smeaton
Mountain Bike Inner tube, Helen Smeaton
Leatherman, Useful Mountain Bike Tool, Helen Smeaton
Bicycle Repair Kit and Brake Pad, Helen Smeaton


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