Motorcycle Tire Change: Triumph
the Fork Oil - Triumph Thunderbird Sport | More on
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for a 160/70-17 Rear Tire Tube
Changing the front tire on a Triumph
Thunderbird Sport motorcycle is a fairly straightforward process, but
there are a couple of issues that need to be resolved to successfully complete
The first problem to be solved is figuring out a way to get the bike up off
the ground. I haven't owned a motorcycle without a center stand in a
long, long time, so I was a bit baffled at how to lift the front of the bike
up to get the front tire off safely. I'm sure there are many ways to do
this, but I opted for the tools I had on hand.
Another slight problem I ran into was the availability of a 12 mm hex tool on
a 3/8" or 1/2" drive socket to remove and replace the front
axle. You really can't remove the axle bolt with an "L" shaped
hand-held hex key, because you'll need to torque the front axle nut to 70NM
when reinstalling it.
You definitely want to make sure you have the
correct torque on this bolt, and you don't want to overdo it by using a
"cheater" pipe over a hex key, as I believe the nut is made of
aluminum or some type of lightweight metal that can easily be stripped.
The problem arises in finding a 12 mm hex tool in socket form -- we'll take a
look at a good substitute.
At this point in time, this is still a work in progress. As we'll see,
after installation of the new tire, I've been experiencing some
"bouncing" of the front wheel. There may be a couple of
reasons for this -- I haven't quite got it worked out yet. We'll take a
look at some of the possible causes, and I'll report back as I make progress
on solving this kind of weird problem. (NOTE:
Problem solved! See below)
When I purchased the bike, the front Avon AV27 tire (size 120/70-ZR17) was
worn down almost to the wear bars, and was moderately cupped (photo, below).
I didn't think it would pass inspection, which is necessary in my
get a new set of license plates, so I opted to replace the tire.
I searched around and found that the AV27 was being replaced by
the Avon AV45, so I purchased a tire, tube and rim strip from the Motorcycle
This company seems like a nice place to deal with;
the tire wasn't in stock, but they found one and shipped in when
he said they would, sent me a UPS tracking number via email, and
followed up when I had some questions.
a friend's rear swingarm stand (I've since acquired one of my own;
see the wBW
of the Steel Horse swingarm stand, which works great on the
Thunderbird Sport). Unless the bike
center stand, a rear stand will probably be necessary to lift the
bike for routine maintenance.
I tried to balance the bike by using just the rear wheel stand and by lifting
underneath the engine with a hydraulic floor jack. But the
bike seems to have a very sensitive point of balance, and the whole setup
was too precarious to work on the front wheel without tipping
I pondered this for a while and came up with the idea
of using a couple
of 2x4's to make up an auxiliary stand that, along with the hydraulic floor jack,
would keep the bike more stable while I
worked on it.
This photo (above) is the result -- something I whacked together in
Next is a
photo of the bike on the rear swingarm stand (in this case a
Lockhart Phillips model; see the wBW
of the Steel Horse swingarm stand, which works great on the
TBird); the hydraulic floor jack (purchased at
Wal-Mart) and the cobbed together wooden stand.
stand really helps to stabilize everything -- it's definitely not
super-secure, but stabilizes the bike enough to allow removal of the front wheel
with some security.
I used a 2x4 placed perpendicular to the bike's centerline and
between the hydraulic jack and the engine to help lift the bike on
the jack. You'll have to be very careful to find the exact
balance spot -- it took me several tries before I found it.
I slowly jacked up the bike, while holding on to the right
handlebar, until the front end lifted off the ground. Then I
slid the homemade wooden stand underneath the rear of the engine and slowly
released some pressure on the jack until the bike was resting on
both the wooden stand and the jack. The stand definitely
gives the bike more stability than just the jack itself.
Note that both the wooden stand and the
hydraulic jack are used together to hold the bike. This helps to
share the load, making the bike stable enough to allow me to
safely work on the
the bike is secure, the next step is to remove the front
wheel. I had these two nylon tie-down straps with a friction buckle
that I got at Wal Mart.
They're pretty much useless for
holding anything down, but work good at holding brake calipers up
to take any stress off of the brake lines. You don't really
want the calipers dangling in the air with all the weight on the
The speedometer cable is held in place with a Phillips head screw
and is easily removed.
the front axle, you'll need to unscrew the 12 mm hex bolt on the
left-hand side of the bike.
This bolt takes 60NM of torque to reinstall, so a torque wrench
should be used for this application. A hex key with a
cheater bar could do it, but this will run the risk of stripping
the threads or failing to apply the correct amount of torque on
this critical bolt.
Sears doesn't carry a 3/8" or 1/2" hex socket, so I
bought a Sears Craftsman 12 mm hex key and used my Dremel tool cutoff
blade to cut off a length of
A 3/8" drive, 12 mm, 6-point socket fit perfectly over this
hex key stub, and allowed me to use the 3/8" drive torque
wrench to apply the correct torque when I reinstalled it. By
the way, I don't believe that Loctite should be applied to this
bolt -- my feeling is that it's at the limit of how much torque it
will take, and the increased effort resulting from an application
of Loctite might result in stripped hex flats on the bolt.
get the tire off, there are numerous ways to break the bead and
remove it (See the wBW Motorcycle
Tires page for information on tires, tire removal, balancing
I usually just take a long (about 6 foot)
2x4, wedge it underneath my car, and place a smaller (about 10")
section of 2x4 over the bead. The amount of leverage I get breaks
any bead very easily. Here's a wBW article on the fastest,
easiest and cheapest motorcycle tire bead breaker I've found!
In this case, I had a couple of C-clamps laying around, and
decided to see how easy it would be to break the bead with
them. This is not a good solution -- I couldn't get the
bead to break on the other side of the tire, and ended up using
the 2x4 method.
I'll stick with 2x4's from now on, because
it's so easy to do and works so well. Just remember to lay
the wheel over a couple of pieces of wood to keep the disk from
hitting the ground while you do this.
problem #1; an issue I'm still trying to resolve (See
below). The tube
that came out of the bike (original equipment, I presume) was
labeled "Avon 120/70-17". It's laying on top of the new tube in this
photo, with the valve showing.
Before I did anything else, I searched the Internet and local bike
shops to see if anyone had a 120/70-17 tube. Unfortunately,
this is a very rare tube size. The Triumph dealer can get
one for $42.00, which is beyond outrageous for a tube, especially
since the IRC cost $6.99!
The tube that was sent with the new tire was an IRC multi-sized
tube. It supposedly fits any 17" tire, from a width of
4.00 to 5.10 or 110/90-17 to 130-80-17. When I laid
the tubes down, one over the other, I realized that the new tube
was much wider than the original tube.
After talking to a couple of shops, and some emails to a couple of
motorcycle lists, everyone assured me that the multi-sized IRC
tube would work.
installed it in the new tire with reservations. The tube really
doesn't feel like it fits properly -- it's hard to get it placed
correctly and it feels like there is too much extra tube being
stuffed under the tire and that it
will fold over and not fit inside the tire.
I'll get a bit ahead of myself here by saying that after
installing the IRC tube and balancing the tire, I took the bike
out and found that it has a repetitive bouncing feeling coming
from the front end. Starting at about 35 mph, the front end
feels like it will start about a 6-7 part bounce, then stop, then
6-7 bounces, then stop, then bounce...... it goes on and on.
Once you get up to around 60 mph it kind of smoothes out, but only
because the bounces are coming with such frequency that they sort
of disappear into the background chassis feel.
At this time, I'm not really sure where this is coming from -- I
didn't ride the bike enough with the original tire to be able to
compare, because I didn't have it licensed because it wouldn't
pass inspection with the old tire (sort of a
"Catch-22"). But I'm assuming this
bouncing is something that has just started with the installation
of the new tire.
tried every suspension setting, front and rear, that I can think
of, and nothing takes out the bounce. So my feeling is it's
got to be coming from the front end, and I suspect the tube is
bound up in there or somehow has too much rubber and is causing
the problem at speed. I took the front wheel off 3 times to
check the balance, which was fine, but the bouncing continues.
I then conducted an exhaustive search to try and find a 120/70-17
tube, but without success. Cannondale's new S440 Super
Motard bike uses this tube and it's listed as Cannondale part
number 5002508, but I haven't been able to find either a dealer or
a tube (Note: Since this article was written, Cannondale's
motorcycle manufacturing unit is no longer in business, so the
part is no longer available).
suppose I should have simply ordered the $42.00 Triumph
replacement, but I guess I'm stubborn -- and I want to see if
there's a cheaper alternative for the benefit of the TBS riders
out there! The answer is... YES1 I have since found that a 4.00-4.50 size
tube is almost identical to the original 120/70-17 and works
fine! Kenda makes a tube of this size, and it can be ordered
by almost any motorcycle dealer in the U.S. through Parts
Unlimited. It only costs about $7.00 too...see
So after some discussions with the local Triumph dealer, we
ordered a Kenda 4.00-4.50 butyl tube. I've heard that the
butyl tubes don't last as long and leak more air than the rubber
ones, but we'll see if this works. It's supposed to come in
this week, and I'll have to remove the wheel yet again and replace
the tube. I'm keeping my fingers crossed....... (see
below for Part II of this saga).
Also -- see below for more
information on finding a 160/70-17 motorcycle tube for the
rear tire of a Triumph Thunderbird Sport.
back at the ranch, I balanced the tire/wheel assembly using Rod
Neff's excellent tire balancing stand (see the wBW
of Rod's balancing stand for more information).
ended up only needing about 15 grams of weight to balance the
tire, which is pretty good for a tubed tire.
dealer also sells Yamaha, and he talked me into buying a can of
this Yamaha Tire Mount Lube. It's meant to be sprayed on the
tire prior to mounting on the wheel. It's pretty slippery
stuff, but it's very messy and gets all over everything. It
gets sticky after a few minutes of exposure to air.
The tire went on the rim with relatively little force, but since I
haven't tried mounting this tire using anything else, I'm not sure
if this product helped it to go on easier or harder than, for example, a simple
solution of water and dishwashing soap.
The bottom line is that I don't recommend this stuff --
it's very messy to use.
One thing I
forgot to do was to correctly line up the boss on the speedometer
housing with the boss on the front axle prior to installing the
front axle when re-mounting the wheel.
finished product -- a brand-new Avon AV45, mounted on the
TBS. I will report back when I've solved the front end
I ended up getting everything back together, then having to take
both brake calipers and the wheel off again to get the speedometer
installed correctly. Don't make my mistake!
This photo shows the correct installation. The speedometer boss (yellow arrow, photo left) must be located
behind the boss on the front fork (white arrow) to help prevent it
from rotating when in motion.
Meantime, this is a great
handling front tire! I feel more confident with this tire
leaned way over than I do on other bikes when I'm going
Bouncing Problems, Part II
I took the front tire off for the 4th time and replaced the oversize
front tube with a 4.00-4.50 Kenda tube. This is definitely a much
better size, and is almost identical in size to the original
120/70-17. It cost $6.99 and should be available at any motorcycle
dealer -- they can order it through Parts Unlimited or one of the other
That's the good part. The bad part is that it doesn't do anything
to solve my front suspension problems. It definitely feels
different, and has helped me realize that I think what's happening is
that the front suspension damping -- the rebound and compression damping
-- are not working as they should. It just doesn't seem like the
settings make any difference, and they certainly don't solve the
So I guess the next step is to pull the front forks and
check/change the fork oil. I may bring the forks in to the local
dealer to give them a once-over and check the bushings. If it's
not the fork oil or the forks, then I'm completely stumped, and there
must be something weird with the chassis of this bike. It's
getting very frustrating......
NOTE: I think I've solved the problem! Believe it or not,
the bike only had 1/2 of the amount of fork oil that is required!
Since the original owner didn't change the fork oil, the bike must have
come this way from the factory. I wrote up the details in "Changing
the Fork Oil - Triumph Thunderbird Sport".
Rear Tire - 160/70-17 Motorcycle Tire
Tube: Since the Supermotard craze, tubes for radial tires have
become a bit easier to find. The Motorcycle
Pro Shop in the U.S. has tons o' tubes: they carry a Metzeler
160/70-190-50-17 tube (their part number 110-6613)
for about $23.00.
In the U.K., you can get a 160/70-17
Pirelli tube for the rear tire at Haines
& Co. for about £9.00.