Tube Maintenance
Tube
Repair
If your tire goes flat, and you deem that the tire is in good
shape, then you will need to inspect the tube. To find the
leak, first reinflate the tire using a pump. Then listen for
escaping air. If you can’t hear anything and the tube
continues to lose air, submerge the tube in water and mark
the spot where the bubbles are escaping. If you see no bubbles,
then the leak is probably due to a leak in the valve stem.
To test this, put a little spit on the end of the valve and
if it is leaking a small bubble will form. The valve may just
need tightening. Use a valve tool for this purpose. If it
leaks, remove the valve core with the tool and put a drop
of oil on the rubber piece of the core, and re-install. If
it still leaks, replace the valve with a new one.
If you see bubbles during the water test then you will
need to fix the tube by putting a patch over the hole. To
do this start by scuffing the area around the hole and including
the hole. Do this with a piece of sandpaper or the metal
scrapper that comes with the patch kit. You should scuff
an area that is a little larger than the patch. Just scuff
it, don’t damage the tube! After you scuff it, brush
away the scuffed off rubber. You can buy a patch that is
self sticking that you simply peel off the back and stick
it to the tube. Make sure the patch is securely stuck around
the hole and test by reinflating it once more. If the leak
is fixed, deflate the tire and reinsert it in the tire.
Remember that the self stick patch is just a temporary fix
to get you home. For a permanent fix, you must use a patch
that is glued on. Everything else is the same in the instructions.
The glue in the patch kits come sealed. Once you open the
tube, make sure the glue inside is thin and runny. If it
is too thick and gummy, it will not hold. Also, make sure
you apply enough glue and place the glue over a larger area
than the patch. Once the shine and wet surface of the glue
turns dull it s ready to apply the patch. It will take about
5 minutes for this to happen. Do not apply the patch until
the glue is dry or it will not stick. Note that most patches
come with a cellophane top layer and a bottom layer of foil.
Hold onto the cellophane and slowly pull the foil off. When
you discard the foil, be careful not to touch the sticky
surface or you will contaminate the glue. Place the patch
on the tube and press firmly. Leave the cellophane in place
as this will help make the sure the tube does not adhere
to the tire when you replace the tube. Once the tube is
patched, you can reinsert the tube into the tire. However,
before doing this be sure to check the tire inside and out
for any bits of foreign objects, like glass, wire, thorns,
etc. which could damage the tube once again.
Tube
Replacement
To place the tube within the tire, first inflate the tube
just enough to round it out and remove any wrinkles. This
slight inflation is the key to avoiding getting the tube caught
under the tire bead, which can cause problem in the insertion.
Next, put the valve stem in the valve hole on the rim and
then work the rest of the tube into the tire. After it is
inside the tire, go around again working the tube up and onto
the rim. When this is done, the free tire bead should be flat
against the rim and the tube should be completely tucked up
inside the tire and onto the rim. To reinstall the tire, begin
by remounting the bead on the opposite side from the valve
hole so the last difficult section will occur at the valve.
This will insure the maximum slack in the tire bead. Hold
the tire in you lap and work your hands away from each other
around the wheel, popping the tire bead onto the rim by pushing
down with your thumbs or the heels of your hands (with your
fingers resting on the back side of the rim). When you get
the last section near the valve, it will get difficult, but
don’t give up. For this last tough section, sit down
and put the section on top of your right knee if you are right-handed
and on your left knee if you are left-handed. Hold the tire
bead on the rim on one side with your weak hand so it can’t
come undone as you work on the other end of this section.
Using your stronger hand, work about an inch of the section
onto the rim. Pop it on by pushing down and forward with the
heel of your hand (you will be pushing against your knee and
you will have a lot of leverage). When you get an inch on,
push another inch on, and so on. When you get to the valve,
push it up inside the tire so the valve’s base, which
is thicker, can’t interfere with the beads as you are
installing the tire. That will help you pop on the last piece
to complete the installation. Next, go around the tire and
push the tire away from the rim, one side at a time. Look
down into the rim to make sure the tube is not visible. If
it is it means the tube is caught under the tire bead and
tire is not seated on the rim correctly. It will not inflate
evenly and may blow out later. If the tube is caught, wiggle
the tire back and forth gently until the tube is freed, or
use a tire lever to gently poke the tube inside the tire.
Once everything is okay, it is time to inflate the tire. To
prevent too much pressure on the valve while pumping, support
the valve stem with your fingers. After you pump some air
into the tire, stop and rotate the wheel to see that the tire
is sitting uniformly. Bulges at low pressure can be explosive
at high pressure. If the tire looks straight, go ahead and
inflate it to the proper pressure. If not, lubricate the beads
with some soapy water and reinflate, or dismount everything
and try again.
Trouble
Shooting Tips For Tire and Tube Repair
Problem: Every time you fix a flat, the tire goes
flat again.
Solution: Check the tube carefully. See if
the holes always occur on the bottom of the tube. If so, then
the rim strip that protects the tube from being punctured
by the end of the spokes may be missing or out of place. If
the holes are on the top, then there may be some sharp object
stuck in the tire.
Problem: The tire goes flat slowly.
Solution: Cover the end of the valve stem
with some spit and watch for bubbles. If bubbles occur then
try to tighten the valve, or remove it and place a drop
of oil on the rubber seal and reinstall. If it isn’t
the valve, then take out the tube, inflate and hold it under
water to find the leak.
Problem: You continually get pinch flats.
Solution: Put more air in your tires.
Problem: The patch won’t stick to
the tube.
Solution: You need to put on enough glue
and let it set until completely dry, which should be in
about 5 minutes. Also, never touch the sticky side of the
patch with your fingers as you will leave body oils. Finally,
do not blow on the glue to “help” it dry as
you may blow moisture on the glue.
References
1. Langley, Jim. Bicycling Magazine’s Complete
Guide to Bicycle Maintenance and Repair or Road and Mountain
Bikes. Emmaus: Pennsylvania. 1999.
2. Milson, Fred. The Bike Book: Complete Step-By-Step
Guide to Choosing, Maintaining, and Repairing Your Bicycle.
Des Moines: Iowa. 1995.
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