tubless tire patching..

A couple weeks ago, before heading to the mountains, I checked my
tires. Rear was down to 18 PSI. Checked, found a thin nail running
at an angle into the center, thick portion of the thread.

I dismounted the tire, went out and bought a tubless patch kit at an
auto parts store, and applied one per the directions.
It didn't stick. Loose around the edges.

Peeled it off, buffed again, then rubbbed the cement in with a
screwdriver handle, scraped off the excess and applied another patch.
After rubbing and hammering it down, the edges looked and felt secure.

I remounted it, checked the hole with soapy water.. No bubbles. It
held up for the weekend of riding.

11 days later, I start to roll it out to ride to work, feels hard to
push. Check pressure.. 12 PSI!..

Tonight, add air, soap over hole = bubbles.

Dismount, peel off patch (very difficult) buff like crazy, add
cement, apply larger patch, pound and rub until it looks like part of
the tire.

Check with soap. no bubbles.

Balanced the wheel, then checked the hole again. BUBBLES! ARGHH!

I've had car tires patched this way, and they've held up. but this is
the first time I've done it myself. I give up. Anyone know of a
good online bike tire dealer?

 

A couple weeks ago, before heading to the mountains, I checked my
tires. Rear was down to 18 PSI. Checked, found a thin nail running
at an angle into the center, thick portion of the thread.

I dismounted the tire, went out and bought a tubless patch kit at an
auto parts store, and applied one per the directions.
It didn't stick. Loose around the edges.

Peeled it off, buffed again, then rubbbed the cement in with a
screwdriver handle, scraped off the excess and applied another patch.
After rubbing and hammering it down, the edges looked and felt secure.

I remounted it, checked the hole with soapy water.. No bubbles. It
held up for the weekend of riding.

11 days later, I start to roll it out to ride to work, feels hard to
push. Check pressure.. 12 PSI!..

Tonight, add air, soap over hole = bubbles.

Dismount, peel off patch (very difficult) buff like crazy, add
cement, apply larger patch, pound and rub until it looks like part of
the tire.

Check with soap. no bubbles.

Balanced the wheel, then checked the hole again. BUBBLES! ARGHH!

I've had car tires patched this way, and they've held up. but this is
the first time I've done it myself. I give up. Anyone know of a
good online bike tire dealer?

I've patched plenty of car tires, back in the day, but never a MC tire. If
you buffed the spot thoroughly, so there wasn't any riblets running accross
the target area, cleaned it with alchohol or lighter fluid or whatever
applied the glue properly (I don't know why you used a screwdriver handle,
the cement usually has a brush or else you could use the patch itself), It's
probably due to the narrowness of the tire and the flexing of the sidewall.

You'll want to use a small patch if the hole is as small as you say and that
might help. You also might want to try a roller to affix the patch. The
ones I used were like a wallpaper seam roller or a pizza cutter with the
business end the size of 2-50cent pieces stacked together. If you start by
rolling across a diameter line and then working it out to the edges it
should hold or else it ain't gonna ever hold. Good luck (I'll bet you
pretty good at R&R-rear wheel by now)

 

If the tire is servicable (not worn out), then take it to your closest
motorcycle dealer. They will fix it cheaply. If the tire is worn out,
then buy a new one.

Maybe someone can advise who has the cheapest motorcycle tires.

pierce

 

A couple weeks ago, before heading to the mountains, I checked my
tires. Rear was down to 18 PSI. Checked, found a thin nail running
at an angle into the center, thick portion of the thread.

I dismounted the tire, went out and bought a tubless patch kit at an
auto parts store, and applied one per the directions.
It didn't stick. Loose around the edges.

snip


A patch is not good enough, as you've found out. You need a plug/inner patch
system (mushroom plug?)
If the tire is a high-speed rated tire that rating will no longer be valid

 

Yannow, ignorance sucks. Not just you, me too. Being ignorant doesn't
mean somebody is rude and crude or immoral and unfit to be around
people. We are ALL ignorant, there is stuff we just don't *know* and we
wind up spending a lot of money on tires that just have a little tiny
nail hole when there should be a simple FIX.

Like what kind of rubber cement besides latex will reliably stick to
the friggin' inner liner of a synthetic rubber tire so we don't have to
buy a new tire to replace the punctured tire that we know will last for
another 7000 miles or more...

There are two reasons that bicycle inner tube patches work so well. One
is that the inner tube is probably made of cheap natural rubber and
latex cement sticks to natural rubber because it's natural rubber too.

The other part is that we immediately pump the tire full of air, and
even if the latex cement wasn't stopping the leak initially, it will
quickly stop when we inflate the tube inside the unyielding tire.
There's a nice firm clamping effect due to internal pressure.

We just don't get that clamping effect with a patch inside a tubeless
tire, and what the heck do they use for glue anyway? Maybe google knows
the answer.

I couldn't get the Metzeler tire I wanted, so I bought a Michelin M59X.
In only 2K miles, it got a puncture and the danged tire patch kit I
bought had latex rubber cement that wouldn't stick to the ribbed inner
liner. It wasn't bad enough that the rubber cement wouldn't stick,
there would be a rib right in the middle of the patch.

And the ribs discouraged me from buying an inner tube to put inside the
tire to eke out the remaining miles, so I wound up paying $135 for a
new Metzeler that I just happened to find in a rundown motorcycle parts
store.

No matter that it was one size too large, I wasn't going to be able to
get a new Metzeler for a while, as the Metzeler factory fire had
stopped production and they were going to be building more expen$ive
Pirelli tires for the next several months.

So far as rubber is concerned, there are at least two types of rubber
used in tires and inner tubes, one is natural rubber and the other is
synthetic rubber and the latex rubber cement in a tire patch kit will
stick just fine to a natural rubber tire (like some of the cheapest
Taiwanese tires) but latex rubber cement won't stick to synthetic
rubber.

And the white gooey stuff inside a can of Seal N Air is also latex
rubber, it's supposed to stick to the inside of an inner tube or a tire
and bond with it, but if you ignore the stern admonition of your local
tire ape and use a can of Seal N Air on a synthetic rubber tire, you'd
better hope the hole is tiny, because the latex rubber just won't do
much.

I remember one time I had a pinhole leak in a synthetic rubber inner
tube and it was rainy season and I didn't want to be out in the parking
lot in the rain changing a tire, so I put three cans of Seal N Air into
that friggin' tube to seal the leak so I could ride to work.

I filled that damned tube with at least a pint of liquid latex glue and
it couldn't seal a friggin' pinhole leak. I found the pin that made the
hole.

I got a puncture in a tubeless tire once and I went looking for a
special non-aerosol sealing goo that didn't expose my local tire ape to
flammable gasses while he was lighting his crack pipe. I figured that
would make him safe and happy,

I couldn't find the sealing goop that was advertised in the magazine,
but the shop I went to had a wonderful invention called Slime. It's
propylene glycol, which is a form of antifreeze and it has fibers in it
that are supposed to plug a hole up to 5 millimeters in diameter.

It plugged the leak all right, but nobody bothered to mention that
Slime is corrosive, it eats holes in the wheels. I wound up with a
severely pitted aluminum rim from the Slime.

Then there are the tire plugs, the gummy worms, the mushroom plugs. The
instructions for installing any type of plug tells you to to star out
by boogering the nail hole out to about 5mm in diameter before
installing the plug. What do you do if the plug blows out while you're
riding at 80 mph and the tire suddenly deflates?

I heard a strange sound as I drove along in my truck with the gummy
worm plug. I couldn't find any mushroom plugs locally so I settled for
the worms. When a worm blows out, the air rushing from the 5 mm hole
makes a "zing!" sound...

Why booger a nail hole out to 5 mm if it started out at only 1 mm?

If the original hole is that small it seems likely that some kind of
thick rubber cement would do the job to seal the hole all by itself.
You wouldn't even need a patch, if you could find a rubber cement that
sticks to synthetic rubber and stays where you put it.

I was gluing some papers with Elmer's School Glue a few months ago and
I noticed the smell of acetic acid coming from it. That's the same
smell that silicone rubber cement has when it's curing.

I looked up the Material Safety Data Sheet for Elmer's Glue and it
turns out that it's just latex, a natural vegetable rubber. I wonder if
Elmer's Glue would plug a nail hole better than Seal N Air, which is
also nothing but latex in an aerosol spray.

 

After about six attempts at patching it via various methods, I solved
the problem. I chucked a large bit in my drill, and bored several
holes in one sidewall. That removed any temptation to keep trying to
fix it and leaves only one option, a new tire

 

I was contracted to install a home theatre/whole house sound system for one
fellow. He specified his own gear and that was fine as the equipment was
high end Denon gear. All was going well even after the installation. He
paid me and was happy. About a week later he couldn't figure out how to
do some advanced function. He called me and after explaining to him what
he was doing wrong, all was OK. He then tried performing another advanced
function. The more he tried, the more confused he became and the more
determined he was not to give up and call me. Then he got into the setup
of the video display. Now he was really frustrated. In the end he threw
the remote, the HT receiver, and a speaker out the window of his 22nd floor
condo. I never did hear what happened after that. He tried to call me a
couple of times after that but I wouldn't take his calls.

pierce

 

After about six attempts at patching it via various methods, I solved
the problem. I chucked a large bit in my drill, and bored several
holes in one sidewall. That removed any temptation to keep trying to
fix it and leaves only one option, a new tire
--
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Spammers are Scammers. Exterminate them.



Good man!

 

The right thing you did was dismount the tire to repair from the inside.
The wrong thing was when asking for help you didn't specify the brand
and model of patch kit. There is a good bit of junk being sold these
days, many are little more than a patch of rubber and tube of glue.

The good patches have a soft underbelly which resembles used chewing
gum, and a darker harder backing.

The surface to be repaired needs to be buffed and ground smooth,
removing any molded-in texture.

Hard for some to grasp but the glue needs to dry until tacky, no more,
no less.

For tubeless tires the best patch is the T-patch. Its a combination plug
and patch.

I can't remember the brand of good patches I buy. All I remember is the
one local professional autoparts store which stocks them. Not Autozone.
Not Advance. Not O'Reilly. Its a NAPA affiliate. The kind of store which
is owned by the man who is standing behind the counter, not one which is
owned by an investor.

 

Wrong. Pressure puts normal forces on its container. The hole in the tube
will naturally cause the air to try to force its way out... the "clamping
effect" is virtually nothing compared to the air pressure force (running
circumferentially along the patch).

My theory: Scrub the crap out of the tire. Any sort of mold release
compound or anything other than pure, rough rubber will cause the
"vulcanizing" fluid not to stick.

 

Oh. So ~five tons of clamping force per square foot is "nothing", huh?

Bzzzzzt! Nice guess, but *wrong* answer. I see bicyclists stopping by
the road for 5 minutes to repair flats all the time. They patch the
tube, pump up the tire and they are on their way. They must be doing
something right!

It's amazing what you can do with air (or its counterpart, so-called
"vacuum").

If you've ever been around carbon graphite and fiberglass lamination or
epoxy bonding, you may have noticed that the fabricator will vacuum bag
parts he's just "glued" together. He will apply a "vacuum" source to
pump all the air out of the bag and use the Earth's atmosphere to clamp
the parts together under a pressure of over one ton per square foot.

The whole Apollo command module pressure vessel that the astronauts
lived in for two weeks was bonded together, using 2-part epoxy and
vacuum bagging.

You can get far more clamping effect with air inside a bicycle inner
tube. If the patch *initially* holds air, and you can inflate a bicycle
tire to 65 PSI, the clamping force on the patch is nearly FIVE tons!

Problem with a bicycle tire is that the latex glue just might blow out
before you get enough air in it to clamp the patch firmly against the
tire. I use two c-clamps and 2 hardwood blocks when I repair a
punctured tube at home.

Bzzzzt! You're throwing terms out that you don't know the meanings of,
Phil. I haven't seen a true vulcanizing rubber patch in decades. Pierce
would know about hot patches.

You had to light the pyrotechnic fuel tray on fire to get the rubber
hot enough to do the vulcanization process. Then you had to get the
fire out before you melted a big hole in the tube you were trying to
patch.

What is "pure" rubber, anyway? You've *never* seen a pure rubber tire
on a car, motorcycle, or bicycle in your entire life. But you have
probably seen pure rubber tires on baby buggies and tricycles that were
built in China or southeast Asia.

How do you know a pure rubber tire? It's light brown, not black. It's
made of natural rubber, from the sap of a tree.

"Vulcanizing fluid". Snork! You mean the latex rubber cement.

Rubber is vulcanized by added a SOLID element known as SULFUR, Phil.
When the rubber temperature is raised to a certain point, the rubber
and sulfur melt together and the sulfur binds the adjacent long chain
rubber molecules together, in much the same manner as polyester resin
or epoxy bonds glass or carbon fibers together in a composite matrix.

Automotive tires are made of what is called "cold process rubber". A
machine called a "mill" is used to macerate and mix the ingredients,
without raising their temperature.

The ingredients are synthetic rubber pellets, which are translucent
white, tan-colored natural rubber pellets, carbon black, sulfur, silica
for wet traction, sulfur for vulcanization in a later stage of the
process, and plasticizer oil to extend the dynamic range of elasticity
of the rubber.

The plasticizer oil is pale amber colored going in, but, since
vulcanization is a reversible process under conditions of rather low
temperature and lots of mechanical stress, the plasticizer oil comes
back out of the rubber. Then it is blue from the carbon, etc. mixed
with it.

At this time, the formally vulcanized rubber is referred to as
"reverted rubber". It's weak and crumbly. When you look at a tires on a
sportbike that has just come in off the race track after "working" the
rubber to its limits, the "smiles" you see all over the tread surface
are reverted rubber.

The plasticizer oil will be all over the outer edge of the tire if the
rider has been working his tires too hard. If he's been gentler on
them, the plasticizer oil will be seen in the large rain grooves as a
pale blue sheen.

 

You see... one mistake and I barely read the rest...

Most tire patches I've seen are about one square inch... maybe two if you
are pressing it...

So that means that the clamping force on your patch is 65 pounds... maybe
130 pounds if you are pressing it...

An earlier poster mentioned that your 65 PSI is also trying to push the tube
edges away, in a shear direction along the patch (think popping balloon),
but I, like you, dissagree with him that the force on those thin edges of
the patch are big compared to the 65 pounds pushing down... and the shear
strength of the glue is obviously enough to deal with it... but I haven't
done the math..

Al...

 

I meant to say that the clamping force on the patch is nearly FIVE tons
*per square foot*. If atmospheric pressure is enough to clamp composite
parts together for vacuum bagging, air inside an inner tube at 4.5
times as much pressure is going to work even better, once the tube is
inflated and the tire cannot expand any further. At that point, the
tube can no longer stretch and shear the latex rubber patch glue. But
if the glue isn't allowed to become tacky before the patch is applied,
the parts don't stick together properly and you can't inflate the tube
to get the clamping effect.

 

No argument from me on the above... But the one difference (though I agree
it doesn't amount to anything in this case) is the fact that your punctured
tube has a hole in it... Vacume bag membranes don't. But as you say once
the tube stretches against the tire, equilibrium is reached, and as long as
the cement doesn't shear up to that point, all should be good...

Al...

 

Glued patches are the key. Try using duct tape and your extraordinarily
powerful normal force to seal a tube. It won't work; I've tried it.

I used to do that, too, until I had all sorts of weird bulges occurring on
the tubes, sometimes resulting in failure. I found that the glue itself was
strong enough. I cut apart the small circles into fourths and then use
those fourths for my bicycles tubes. Even in my 120psi tires they're just
dandy!

Have you used glueless bicycle tube patches? Total crap. The air always
leaks under the tube and escapes out the side, all the way to the edge of
the patch. Crap, I say. So obviously the air pressure isn't just pressing
the tube against the patch against the tire, or else this wouldn't happen.

I knew it isn't true vulcanizing fluid. That's why I put it in quotes. If
you open up most bicycle patch kits, the tube of glue itself is labeled
"vulcanizing" fluid, probably a holdover from ages ago. I wasn't sure what
else to call it, so I called it how it's commonly misnomer-ed.

In the bicycle industry we call them butyl tubes. Not really sure what that
means.

Thanks for the enlightening other info on the rubber deal, though.

 

Doug Warner wrote:

Re: tubless tire patching..

You really should just get rid of the tub. Stick with tubes, instead!

 

Butyl rubber is synthethic rubber. It was invented in the 1930's or
1940's when the Japanese captured the strategic supplies of natural
latex rubber. Butyl rubber has that dead skunk smell of butyl
mercaptan.

Natural rubber glue containing latex doesn't stick to synthetic ruber
very well. That's why aerosols like Seal N Air don't work to seal
synthetic rubber inner tubes.

Natural rubber inner tubes are usually thicker and gummier than
synthetic tubes. They are self-healing to a certain extent because the
thicker rubber tends to seal small holes.

As I recall, the scientific name of the latex tree is Latex latex, but
it's possible to make natural rubber out of a low bush that grows in
the deserts of the southwest if it can be commercialized.