I debated on where to put this, and decided on
Thumpers as we probably change our tires the most in here. Maybe it belongs in
"The perfect line" but I've never been in there, and it seems to compliment
Creepers excellent tube thread pretty well. So here goes.
It is a sad
fact of life that motorcycle tires are a short lived affair, especially the
knobbly ones that so many of us enjoy punishing in the dirt. During the summer,
I change tires every other week, or at most, every third week (either putting
new ones on or rotating old ones to utilize the sharp side of the knob). Because
I do it so much, I have gotten better at it than I used to be, and I thought
perhaps I could share that hard won knowledge.
These pictures happen to
have been taken changing dirt tires, but the techniques shown here apply equally
to street tires (well, maybe not the bits about rim locks and tube positioning).
Later this week, I'll throw new tires on the GS and will document that as
well.
Tire changes are not difficult. In putting together this set of
directions, I changed both tires on my KTM at an unhurried pace, including
shooting 72 pictures which took lots of time to pose, and including cleaning and
greasing axles, checking brake pads, and validating spoke tension, in 54 minutes
from first picture to last. I never used more than moderate force, did not break
a sweat, and no curses were uttered.
A few things to have in mind as you
approach this project.
1) If you are using force, you are doing it wrong.
You are not stronger than the tire bead, and you don't want to be (broken beads
mean wasted tire). If things are not happening easily, THINK about what forces
you are putting on the tire and reposition things to align those forces with
what you are trying to do. Like most things, tire changes are more a mental
exercise than a physical one.
2) The devil, as they say, is in the details. A
small change in position or etc can make all the difference. Pay attention to
the subtleties of what you are doing. The single most important thing to notice
is that the profile of the rim has a dish, or a low point, at the center where
the spokes join. This dish is your friend- if the bead of the tire is resting
down in the dish, it will be loose on the opposite side. If not, not even a 50
HP dirtbike can break it free.
3) Always look at the side of the tire
opposite where you are working. All of the tension that you are working around
is generated over there, not at the point where the tire iron is contacting the
tire.
Again, these same approaches will apply to street tires as well,
but I'll just focus on the pictures I have for now and worry about the others
later.
Tire Removal:
We'll assume, for a moment, that you are able
to get your bike situated so that the wheel in question is free, and are able to
remove it, and so we'll start with the wheel off the bike and go from there.
I like to change tires using the new (or old) tire as a rest for the
work I'm doing. The primary reason for doing so is to keep the sprockets and
brake rotors off the floor and unbent. Lots of companies make nifty stands, but
I've never been able to justify one given how well another tire
works.
Step 1: Let air
out. Remove the valve stem all the way, so that the tube can "breathe" as you
change the volume of the tire through your manipulations. Tip: loosen the valve
stem nut, if you have one, prior to letting the air out.
Step 2:
Loosen (but do not remove) Rim Lock. Once the nut is loose, push the stem in to
make sure that the rim lock has released its grip on the tire carcass. You may
need to hit the stem with your socket hammer that you used to loosen the nut to
get it to let go.
Step 3: Break the
bead. On dirt tires, this is no big deal- I'm doing it here with my chaco'd
foot. I can also do it by hand, if I feel like getting dirty. This is the
biggest difference for street tires; we'll get to that later. If you're feeling
uppity, turn the tire over and break the other side right now too, but chances
are good that it doesn't really matter, that it will come free during your other
manipulations anyway.
Step 4: Insert 2
tire irons, 4-6" apart, 90 degrees off the valve stem and/or rim lock. You
don't want to go opposite the stem or rim lock because then the bead can't seat
all the way into the dish of the rim. You don't want to be anywhere close to
them because they will make it harder to get the bead out. So, split the
difference.
Step 5: Start
working around tire away from initial "bite", inserting tire irons close at
first and farther as the bead gets looser. Tip: if the tire is making it
difficult to get the iron inside the bead, insert the tire iron just out from
where the bead is crossing from outside to inside. It will be a very small bite,
but it will be easy to get the iron in.
Step 6: Continue to
work all the way around the tire until one whole side is off. Step on the middle
of the rim and pull the tube out, taking care to ease the valve stem out through
the hole in the rim.
Step 7: Flip rim
and tire up to vertical, and insert tire iron as shown to pull second side
toward the same as the first. Use the other iron to pull the bead off. Once you
get about 1/4th of the way around, you should be able to simply jerk the rim out
of the tire.
Congratulations.
You are now halfway through the project.
A few words before we get started on installing the new rubber.
Your
primary task in installing a new tire is protecting the tube from damage. You
want to make sure the tube is lying straight throughout the tire, so that it
won't chafe on itself and cause a flat. You want to make sure not to damage the
tube with the end of your tire iron. You want to make sure that the valve stem
is nicely aligned with the hole in the rim, so that it doesn't rip the stem from
the tube upon shifting.
New KTM's often locate the valve stem hole
relatively close to the rim lock hole, which is very convenient for tire changes
as we are about to see, although it does not help the balance any. However, many
other makes will have the valve stem and rim lock opposite- I'll cover that
eventuality in a moment.
Some dual-sporters like to run 2 rim-locks, to
improve tire balance. I've done this, and it does help with balance, but it's a
bitch to install, and no way around it. We'll save that for the advanced class.
Personally, I never bother anymore. I really can't feel the difference when push
comes to shove.
As above, if doing the rear wheel, it is nice to work on
the side opposite the sprocket. Plan accordingly.
I do not use any soap
or water- I prefer the tire to be a little sticky, so that it holds position as
I work on it. Others disagree with me. Experiment and make up your own
mind.
Step 1: install the valve stem and add some air to the tube. The
goal is to give the tube enough body to roll itself out of the way of the tire
iron or etc, without making it hard to get the bead into the dish of the rim.
Another important function of adding air before you start is that it will ensure
the tube lies flat, with no twists or kinks, inside the tire.
You will
be hard pressed to flat the tube with your tire iron if you have added some air
first.
Step 2: Install the tube in the tire (I cheated here and put the
tube in the tire before adding air).
Step 3: Align
tire/tube combo with rim/rimlock combo, so that valve stem is ready to pass
through the hole.
Step 4: If the
valve stem and rimlock are in the same quadrant of the wheel, you've got it
easy, because you can pass the valvestem through the hole in the rim, and align
the rimlock all at the same time.
If they are opposite, just worry about
aligning the rimlock for now. I'll show pics of how to deal with the valvestem
in a moment.
Aligning the rimlock- you want to push the rimlock down, so
that it is between both beads of the tire and when the time comes, can suck the
beads up and into the rim as it is designed to do. Trust me- if the rimlock is
not inside the beads, you will not pass go, and you will not collect $200 no
matter how hard you try.
Here the valve stem has passed through;
And
here the rimlock has been pushed between the beads and the tire is ready to be
pulled on.
Step 5: Pull the
first side of the tire down onto the rim, taking care as always to keep the bead
in the dish of the rim.
If you could
not slide the valve stem in at the outset, here's where you do so:
Note that the valve
stem is aligned with the hole it will pass through.
This picture sucks,
but all I'm doing is shoving the valvestem inside the tire.
And this
picture sucks too, but I'm lifting up the tire from the opposite side (the one
that is already on) so that I can move the valve stem into the hole.
So, now we've got
one side of the tire on, the valve stem and rim lock positioned correctly, and
the second side completely off. We're in the home stretch.
Step 6: The
second side of the tire. You want to start with the portion of the tire
immediately adjacent to the valve stem, so that the bead of the tire won't trap
the tube adjacent to the valve stem.
From there, you
want to work the shortest route toward the rimlock. If the rimlock and valve
stem are exactly opposite each other, whichever direction will be
fine.
And finally, you
want to finish the tire off 90 degrees from the valvestem and rimlock, so that
they are not in the way of getting the bead into the dish of the rim. As always,
take care that the opposite bead is down in the dish…
Step 7: Air
the tire up. Always fill tubes slowly- not from a 120 psi compressor that's all
charged up. Filling the tube too quickly can result in a twist that does not
resolve itself. Bicycle floor pumps are best, but if you must use a compressor
(I do), just switch it off once it hits 40 psi or so.
Step 8: tighten
the rimlock- this should always be done after adding air to the tire, so that
the tube has no chance of being caught between the rimlock and the tire bead,
AND so that the tire has the best chance to seat
evenly.
Done!
Mmmm... Fresh Meat...
