Many bike companies at the moment are
pushing tubeless tires and wheels.
For those who don't know tubeless tires are
similar to a clincher tire in that
they're an open cross section but they
actually form an airtight seal against
the rim. Now instead of putting an inner
tube inside the tire you actually inject
sealant in there and this is designed to
fill any holes that happen if you get a
puncture. But what happens if you get a
puncture on a tubeless tire? Do they
actually work? Here I've got an American
classic road tubeless wheel with a Bontrager R3 25 millimeter tubeless tire
and inside this it's pumped up is some
Bontrager sealant as well. Now I've been
riding these wheels for a while and
bizarrely for a change I've actually
been wanting to get a puncture just so I
can see how effective they are. Although
it strikes me that I may have actually
got a few punches but they've sealed and
I've never noticed so I've decided to
force the issue and actually see how
effective the sealant is. So the first
test I'm going to do is I'm actually
going to put a line of drawing pins or
thumbtacks if you're American, through
the tire and see if it punctures it and
see if they actually managed to seal the
holes as well.
So we've got five pins firmly embedded
in the tire here and the ties at the
moment perfectly inflated there's no
loss of pressure at all. So I'm just
going to take them out and see what
happens you can see a bit of sealant
coming out there in a bit of sealant
there as well and there's a hissing
noise i'm just going to spin the wheel
because that's what would be happening
if you were riding you can see the dots
of sealant but now there's no hissing
noise the air stopped so although
there's a bit of sealant there that's
that's stopped and that sealed. So there
you have it within seconds all those
holes have been sealed by the sealant
inside the tire and it's quite
impressive actually in pretty quick and
there wasn't much air lost from the tire
either it was done pretty quickly. So now
that we've seen that the sealant can
more than seal off thumbtacks let's see
now if it can stand up to something a
bit more heavy duty so to test this I've
got a nail which are the represents a
bad day or some particularly malicious
spectators at a cycle race. Now by all
means try this at home but if you do use
safety specs like me as if this is going
to actually work right.
So we've got the nail it's halfway
embedded in the tire part of me was
expecting the tire to actually explode
as I just hit the nail into it but it
survived so far so let's take it out and
see if it actually manages to seal this
big hole and see what would happen if
you were on a ride.
So it's here the air coming up, Oh, covered in feeling so there
you can see the sealants coming out the
hole that's incredible that's actually
sealed that massive hole look wipe it
away it's gone on you can not hear the
air hissing out anymore so there's no
air coming out of there anyone still
loads of air pressure in there as well
that's impressive. After about 20 seconds
it had managed to plug the hole and seal
it I was not expecting it to survive a
nail being driven through the tire
carcass. You can easily ride home on this
tire even with the air that's been lost
and you could always top it up with your
mini pump as well so yeah it's a win for
the tubeless tire. So if you're running
tubeless your chances of punctures is
much much less but you can still get a
puncture and sometimes the hole will be
too big for the sealant to seal it.
If that happens though it's not the end of
the world because you can actually put a
piece of old tire inside your tire to
cover a big hole and then put a regular
in a tube inside and pump it up as normal.
But one thing to remember is that
fitting tubeless tires to achieve this
rim can be quite difficult and it can
be a tighter fit than a normal clincher
set up some combinations of tire and rim
can be a lot easier but this particular
combination of Bontrager R3 tire in
this American classics trip I found it
really difficult and I really wouldn't
want to have to do it on a cold wet day.