Always carry a tool kit - any good ride is likely to take you further from your house or car than you would like to walk.

Check what you need to remove every component of your bike. Multi-tools are compact, but may be fiddly to use on some repairs. Basics are…

Sometimes you just don't have the tool you need. Get creative!

• 8mm Allen wrench = 5mm and 3mm side-by-side (10mm = 6mm + 4mm)
• Small bolts = Slide coins into gap between bolt and wrench, on side that will NOT be applying force to the bolt.
• Metric bolts, SAE wrenches
  • 8mm = 5/16 inch (approx.)
  • 11mm = 7/16 inch (approx.)
  • 13mm = 1/2 inch (sloppy fit)
  • 16mm = 5/8 inch (approx.)
• Chain breaking = 2mm Allen wrench to rest against rivet, rock to pound against Allen wrench, log to rest chain on, and a sacrifice to the tool gods to appease them for the mangling of the wrench.
• Lock ring pin tool = Two small Allen wrenches, short end in holes, handles held together.
• Cassette lock ring removal tool = Hold a screwdriver against the splines, and hit it with the palm of your other hand.
• Chain whip (for cassette removal) = Loop chain around cassette, slide 3mm Allen wrench between chain plates for grip.
• Lube =  Lip balm, oily sunscreen, fork oil (if it’s really desperate)
• Thread lock = PTFE tape, plastic bag.
• Thread chaser = Knife blade, screwdriver, another nut or bolt of the same thread type
• Drill = A nail or screwdriver will work at a pinch in plastic. Heat up with lighter or better still light a small fire with the lighter, and heat the screwdriver in that. Be careful to localize the heat to the point, as the handle may well melt off. Nails may be held in pliers.
• Helper bar for stubborn bolts = *thick* aluminum or steel seat posts can be slid over Allen wrenches to provide more leverage. Be careful not to deform the seat post as it will never go back in to the seat tube if damaged.
• File = Rough rock. Consider finding a big rock and taking the component to be filed to the rock as this gives you a bigger filing area and more control over angles, etc. Some multi-tools and knives come with a file area on the edge of one of the blades.

Sometimes you are missing that vital component as well - I mean, Park may very well sell tire boots, but who really carries them on the trail?

• Bolt replacement = Find similar from bottle cage, cycle computer mount, seat post clamp, headset compression/stem cap bolt (this one isn’t needed once stem is tightened), brake bosses, shoe cleats…
•  
  Remove one from a set (one of the six rotor bolts, one of four or five chainring bolts)
• NOTE: do not remove brake boss bolts from forks with bolted on arches (older Marzocchi, for instance).
• Washer = Aluminum drink can pull tab
• Shim (to “pad” components so they don’t slip) = Aluminum from drink can.
• Thicker shims – use old inner tube.
• Tire boot (fixes gashed tires) = Energy bar wrapper, race number plate, denim (jeans pocket?), duct tape, dollar bill (wears out fast – gets expensive).
• Replacement brake fluid
• DOT4 brakes: take from the brake fluid reservoir in almost any car
• Mineral oil brakes: use mineral oil from a pharmacy/drug store.
• NEVER use other types of oil. They may work fine initially, but they are likely to expand when hot, leading to the brakes locking on after a short descent.
•  
  Replacement fork oil, oil bath forks
• Motorbike suspension oil, around 7-10 weight if possible.
• Automatic transmission fluid as a last resort. Some oils can cause longer term damage to rubber seals in the fork.
• Wire/zip ties/rope = Compression straps, webbing from backpack or hydration pack, packing tape, baling wire, fence wire, plant fibers.
• Padding (missing saddle, etc.) = Clothing, backpack.