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Flat Tyre
A
puncture is the one event that happens all too regularly when you're riding
off-road. Always carry a pump, spare tube and puncture repair kit.
  1.
Remove the wheel by releasing
the brake cable, undoing the quick release and then unscrewing it a few
turns.
2. A good trick to encourage
your rear wheel to drop out easily, and make putting it back in a snip,
is to first select the smallest gear in your rear cluster.
 3.
You'll need to use two tyre levers in tandem to force the tyre off the
rim. Place the flat end between the rim and the tyre. Lock one lever in
place by hooking it onto a spoke, run the other around the wheel circumference
to ease the tyre off.
4. Extract
the tube from underneath the tyre (sounds like a dental procedure). Punctures
generally are the result of either a snake bite (the tube is pinched by
the rim - caused by hitting a big bump with a tyre that is too soft),
or a sharp object making a hole (often gorse prickles or matagouri thorns).
The prickle will most likely be still embedded in your tyre, so carefully
check the inside by touch and sight, and remove the offending blighter.
If you take the tyre off the rim, ensure you put it back the right way
round (the rotation arrow on the sidewall should match the direction the
wheel rolls when you travel forward).
 5.
If your spare tube is still intact then use it (repair the wrecked
one when you get home - fixing tubes in the field is a pain and should
be
avoided if at all possible). Partially inflate the new tube. Tuck it
under the tyre and place the valve through the hole in the rim. Starting
at
the valve, ease the tyre back onto the rim. It gets tricky as you complete
the circle (how Zen) - use your whole hand to roll the tyre on.
6. Don't
use tyre levers - they tend to pinch the tube causing a further puncture
and considerable audible obscenities. You may need to let a little pressure
out to complete the manoeuvre.
Pump
it up
 There
are two common types of valve: Schrader (just like on a car) or Presta
(also known as a French valve). Any
decent pump can handle either type by juggling a couple of its components:
a rubber sleeve and a "pointy" valve depressor. Schrader valves require
the wider diameter to fit over the valve with the depressor sticking back
into the valve. For Prestas, reverse both pieces so the pointy bit is
aiming into the pump, and the smaller diameter hole fits around the valve.
For the details, check out the operating instructions for your model pump.
 Ensure
valve is seated properly, so it is straight up and down in the rim. Now
pump the sucker up. Try it with the wheel upright and the valve at the
"12 o'clock" position. Wrap your thumb and fore finger around the tyre
and the pump, to hold every thing in place while you give it the kiss
of life.
The
tyre pressure should be between 60psi (bloody hard) and 35psi (can depress
about 5 - 10 millimetres with your thumb). Firmer is better on the road,
softer for when you need more traction, eg muddy, wet conditions. Lighter
riders can get away with lower pressures. Put the whole catastrophe back
together - spin the tyre to make sure nothing is rubbing and you're away
Tube
Repair
 Find
the leak - not always a simple task. Inflate the tube until it's obese
(about 75mm diameter). You'll be able to hear or feel air escaping (use
your cheek or the back of your wrists). For slow leaks immerse the tube
in water - little bubbles should lead you to the leak. Mark the spot (crayon,
white chalk or twink works a treat) and deflate the tube. Stretch the
tube over the handle of your pump, roughen up the surface with sandpaper,
then smear vulcanising solution onto the tube (covering slightly larger
area than the patch you're going to use).
 Once
the solution is tacky dry (about 5 minutes), peel the foil off the patch
and press it firmly onto the tube (stretched over your pump again). Use
pump like a rolling pin to apply extra pressure. Leave to set for a few
minutes, remove the plastic film and inflate to test the seal and make
sure there are no other holes (be warned - snake bites usually come in
pairs).
Broken
Chain?
 Locate
the damaged links and nut out which bits you will need to remove - ensuring
you're left with a male and female end. Whip out your chain breaker and
squeeze the pin through to release the damaged link. Be sure not to push
the pin out completely.
1.
Re-thread the chain around your drive bits - especially the front derailleur.
Join the two ends together by squeezing the pin back in. Note that some
chains require a special oversize chain pin - check with your shop.
 2.
Use the spacer to ease the links so they move freely. If the chain is
getting a bit short insert your spare links or limit your gear selections
to the smaller cogs.
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