- We often talk about tires
being one of the most important
parts of a mountain bike.
In particular, the tire pressure
that you run them at and the tire tread
that your particular tires have.
Because they can be instrumental
in how your bike handles off-road.
There can be a lot more to a set of tires
than you might initially realize.
Let's talk tire tech.
At GMBN, we use Vittoria tires,
but in this video the technology
I'm going to be talking about
is largely seen across various
different tire manufacturers
so I will be name
dropping different tires,
models, compounds, and things
like that where relevant.
Just for clarity in this video,
I'm just going to show you
what I'm going to be talking about here.
So you've got the tire bead itself,
you have the casing that joins
the two sections of beading together,
you have the tire tread of
course, that sits on the top.
That's the bit that keeps
you connected to the dirt,
and then on the sidewall,
you have all the
information about the tire.
Expect to see things like the model name,
the sizing here, the ETRTO measurement,
which we're going to get
into later in the video,
and even things like the rubber compound
that the tire uses.
(relaxed electronic music)
So first up, we're going to
talk about the tire casing
and the bead, because fundamentally,
this is the foundation of the tire.
No matter how good the rubber is
that you put onto a tire, if
you don't get the basics right,
it's simply not going to handle well,
and you're going to end up
with an unreliable tire.
Now, first up we're going
to look at the beading.
Now, the beading itself is what
holds the tire onto the rim.
This is really important
for a tire to get right.
Thankfully, most manufacturers
seem to have this nailed these days.
But you do still get
some different materials
that do handle slightly differently.
You get steel beading,
which you used to see
in downhill tires, and
you sometimes still see
on cheaper end tires.
Nothing wrong with it,
it's just a bit weighty.
Higher-end tires tend to
have, like these ones here,
Kevlar or aramid beading on them.
And you can also get some
folding orientations,
you might notice this
one here is coiled up,
this is a folding Kevlar bead there.
Now, you'll often hear things
called TPI referenced with tires.
Now, that TPI reference
means threads per inch.
Quite simply, tires
used to be manufactured
from cotton thread back in the day.
And in fact, some high-end road tires
are still in fact made from cotton
because they do offer a ride quality
that you can't get with other materials.
But one of the downsides
with cotton as a thread
used in a tire is the durability.
So later on, tires started
moving into nylon thread.
And you tended to get 60 and
120 threads per inch on tires.
Now, in the road world they go up to 320.
The reason for that is they're
using much thinner threads
on there, of course, they want a tire
that's extremely lightweight
and still manages to be quite
comfortable on the road.
In the mountain-bike world, 120 and 60
are the two common options.
Most higher-end tires tend
to be 120 threads per inch,
whereas downhill tires and
cheaper tires tend to be 60.
Now, the reason for
the 60, it doesn't mean
that you're suddenly going
to see loads of holes
in between those threads,
they're just as closely packed,
it's just the threads
themselves are much thicker
and much more durable.
As a result, the tire's better
for impact resistant stuff
like downhill racing, against rocks
and stuff like that.
There's a downside to
it, because of the fact
there's less threads and
the threads are much bigger,
the tire's not going to
be as compliant off-road
and you can suffer from
a bit of a wooden feeling
by comparison to the 120.
That's all you need to know about TPI.
Moving on from the TPI,
we go into the tubeless
ready part of tires.
Now, because tires are actually,
'cause of their construction,
they're still threads
at the end of the day,
as referenced in the TPI,
you have to make that sealed.
Quite simply, what makes
a tubeless ready tire
is a tire that's had a layer
of latex and ammonia mix,
there's various different materials
depending on which tire
is manufacturing them,
that effectively seals in
that inside of the tire there.
So you can put a tubeless
ready tire on a rim
and inflate it, you don't need the sealant
to make it tubeless compatible.
It will hold air, although
it's not recommended
to keep it like that because
you can still suffer punctures
and it's not going to stay up, basically.
Tire ply is something else
you're going to hear
referred to with the casing.
You get single ply,
which you typically see
on much lighter tires,
like cross country tires.
The reason for that, quite
simply, is it's a lot lighter.
Cross country wheels are all about
minimizing that rotational weight,
so you need those tires.
The downside of a single ply,
compared to a dual ply tire, quite simply,
is the fact that it is far
less puncture resistant.
Now, if you look at a dual ply tire,
they're much thicker, you see,
this thing almost wants
to stand up on its own,
it's a very tough, thick tire.
The downside to this, of course,
they're going to weigh more.
So some manufacturers get around this
by offering somewhere in the middle.
You might hear of casings,
for example from Maxxis,
they have their EXO.
Which is actually a single ply casing,
but they put inserts in the sidewalls
just to give you a little
bit more protection
whilst also retaining that light weight.
You get the same effect
with Vittoria tires,
you've got single ply tires,
you get the trail tires,
which are also single ply
and they've got sidewall protection,
and then you get the
big heavy enduro tires
which are dual ply.
You also see, as you can see
on this particular tire here,
they've got butyl inserts
in the actual sidewalls themselves,
so they're incredibly
resistant to burping,
folding, and wallowing.
Definitely something looked at
and looked for by enduro riders,
downhill riders, and
people like Blake, really,
the sort of riders that turn any turn
into a 90 degree (clicks
his tongue) sort of thing.
That's what you want, the sort of support
you can get from a dual ply tire.
You're certainly not going to be caring
about the weight if you ride like that.
One thing that's particularly cool
about the sidewall inserts is,
some of you might've
suffered a pinch puncture
right down by the beading itself.
If you have, you'll know it's
nearly impossible to fix.
Even if you set your tires up tubeless
and use one of those tubeless plugs
that you force into the tire.
It can just never really seal properly,
so by having a butyl insert
in the sidewall of the tire,
it means it's incredibly resistant
to getting tears right
down there by the bead.
If you ride hard, really,
safe yourself some money
and at least spec a heavy duty like this
on the rear of your
bike, where you're likely
to get that sort of damage.
Okay, so let's talk about the tire size
or the casing size.
So you might hear about 2.3
inch tires, 2.5s, whatever,
all that information is on the sidewall.
Now, when tire manufacturers
produce the tires,
they have to adhere to
the European Rim and Tire
Technical Organization,
or the ETRTO measurement.
That is written here on
the sidewall of the tire.
So where you might judge the tire
by seeing 2.3, like it
says in this case here,
the real measurement is actually
written underneath that.
This one is a 58-622.
That is the millimeter size.
The 622 is simply referring to the fact
it's the 29 inch wheel tire.
622 of course, is the outside measurement
of that rim, which is 24.5 inch.
By the time you put a big tire on it,
factor that in on each side of the rim
and you have a 29 inch wheel.
Yeah, shock horror, 29 inch
wheel is actually 24.5 inch.
The millimeter measurement
at the beginning here,
58, in millimeters, that is
actually slightly under 2.3,
they put the average size
and what it actually
correlates to on the tire.
So if you want the true
measurement of a tire,
look at the millimeter sizing right there.
Now, there's also a fairly new thing
called the Global Measuring System
that some tire manufacturers
are choosing to use as well.
So in addition to the measurements
you see on the sidewalls,
this one here I've got says 57.
WTB, for example, are actually
providing two measurements.
They actually measure at
the shoulder of the tire
which is quite often on aggressive tires
wider than the actual
biggest bit of the carcass.
And they'll also quote the carcass.
So it might be 57 and 60
with the 622, just to give you
a little bit more perspective there,
so you might see that creeping in
amongst a few other tire brands,
some tires are certainly a bit
more aggressive than others.
Now, what does rim width
do to tire profile?
Well this one is fairly
easy to describe, actually,
and in fact just to reference
Stan's NoTubes here,
they've actually got a
very cool illustration
on their website, showing
exactly what happens
if you run a tire, the same size tire,
on three different rim sizes.
In the middle, you've got the wideright,
is what they call it, on the
right you've got the bell
and on the left you've got the light bulb.
So what they're referring to here is,
if I use this tire as an example,
if you were to run this
on a very narrow rim,
you get a very round profile on the top.
The shoulder tread of the tire
is not going to do its job properly
'cause it wasn't designed
to fit around a rim
that's this big, and of course,
that gives you that kind of light bulb,
that bowl sort of shape.
If you're running a tire
on the correct sized rim,
you're going to get the profile
the tire was intended to be to do its job.
It's got a good sharp edge,
but it's also rounded enough
to make the transition
from the center tread
towards that shoulder tread.
And then, again, if you're
running on a super wide rim,
you're going to square it off so much
that you're actually going to get
a bit of a Jekyll and Hyde
characteristic to the tire.
Because there's no real transition
from the flat center
tread to the shoulder.
You're basically trying to
corner straight onto an edge.
So therefore it is quite important
to factor in the rim width.
Most tire sizes you will have,
they'll have a recommended rim
width to correlate to though,
so that is quite important.
Okay, so now let's look at the tread
on a set of tires.
The tread, of course, is essentially
what keeps you rubber side
down when you're riding.
Now, there's lots of
different tire tread options
out there to suit all different
sorts of riding styles
and all sorts of different
riding conditions as well.
As well as disciplines that
you're going to be riding within.
You're not going to want
to run a semi-slick tire
on a downhill bike, nor are
you going to want to run
a heavily spiked tire
on a cross-country bike,
they're very specific.
Now, you could go chopping
and changing your tires
all year round to suit
different riding conditions,
or you could pick a set of tires
that works well for most conditions
and learn, basically,
how to ride that tire
in all conditions.
There's no right or wrong way,
and nor is there an ultimate tire.
There are lots of different
options out there.
So let's break down the features
within tire treads, so you can understand
what you need to look for
to pick the right tire.
Okay, so first up we're going to look
at the shoulder of the tire,
so this is the outside edges of the tire.
And in a similar fashion
to snowboards and skis,
this is what you want to
cut into that terrain,
an edge, if you like.
This is really important
for traversing cambers
and getting a good amount
of grip when you corner.
But the key to a good
shoulder is the transition
from the center tread to that shoulder.
If the tire is too square, for example,
there is no transition, basically,
you're on the edge straight away.
And if it's too round, then really,
it's not going to work out that well
'cause you're going to have
less of an edge to cut in.
This is really important
why a tire like this
has got such a defined shoulder,
that you pick the
correct width rim for it.
If you go too wide, too
square, too narrow, too round.
Of course, some other tires
they don't have quite
so pronounced shoulders.
Now, this tire is a bit
more of a rounded profile,
it's actually a cross country tire.
This one's called a Peyote.
The idea behind this is the fact
that it's rounder in general
because you don't change direction
in an aggressive way on
a cross country bike.
You kind of want to be smooth
in all of your actions.
So whilst it has got quite a
good angled shoulder there,
the transition to it is nice and relaxed.
Now, the central part of the tire
really does alter the way
a bike can handle off-road.
This particular tire
is a cross country tire
and you can tell the fact
it's designed to roll fast
'cause it has a fairly central ridge
running all the way down the tire.
This is going to be
extremely fast rolling,
but it does have a couple of downsides.
Because of that central ridge,
it's going to suffer
slightly in looser conditions
when accelerating, and
the same under braking.
Because of that constant
contact patch with the ground.
You get a very different sort of handling
with a tire like this, for example,
which is more paddle based.
It's going to roll a lot slower
than one that has a central band,
but it's going to cut in a lot differently
under both braking and acceleration.
When looking at paddle
designed tires like this,
think of them as like a paddle steamer
or even like a sand tire
on a motocross bike,
the whole point is it literally cuts in
and propels you forwards.
And the same thing under braking,
it cuts in to slow you down.
It's all about how the tire
interacts with the ground.
Now, despite the fact that this tire
has a central ridge
running down the middle,
you might also notice that it's got
a slight chevron style to that pattern.
And the reason it's got a chevron style
is when you're cornering, of
course it's very different,
the way you corner a tire like this,
it gives a bit of an edge
or a bit more of an edge
than it would otherwise have.
You got to think that this is
a very low stack height tire,
it's a very fast rolling style tire.
The knobs are very close together.
So it's going to phased
with very technical terrain
but it's about keeping it predictable.
A predictable tire is far better
than a tire that's massively
good in one situation
and horrendous in another.
Predictability is the king.
The stack height of the actual knobbles
on your tires as well, also
makes a significant difference.
For example, on the right here,
this tire is a Mota,
you might compare this
to other similar tires on the market,
a Magic Mary, or the Shorty for example,
it's very open, and it's
got very deep tread.
Very similar to a lot of motocross tires,
the whole idea is the
tire can really cut in
and give you good purchase on the ground.
Accordingly, because of the
fact the tire's quite high up
on firm ground, it can
squirm around quite a lot.
You could say, like a four by four tire
compared to a low profile
tire on a sports car.
The low profile equivalent
would be something like this tire.
Everything here is a lot lower down,
which means on hard terrain,
it's not going to squirm around,
you can really push it into things
and your tire is going to
remain feeling very predictable.
It's something to definitely factor in
when you're buying your tires,
where you're going to use them,
the conditions you're
going to ride them in
and how you're going to ride.
Now, usually, on mountian bike tires,
you'll find they are directional.
Which means there'll be an orientation
to the way the tire has to rotate.
You see here on the sidewall,
it's got a clear marking here
with an arrow pointing forwards.
That is to go with the rotation, i.e.,
I'm going forwards, the tire
is going to rotate that way.
The reason for that, if you
look at this tire pattern,
you can actually break
down what it's going to do.
It has a staircase on the forward side
of these knobbles here.
You might see this in the form of a ramp
on some other brand tires.
The whole point is, that style profile
when you're moving forwards
basically has less rolling resistance.
But you also notice the back
side of the knobbles here
is vertical, the reason for that
is that's what's going to
cut in when you're braking.
Whole point is to roll as fast forwards
as you can go, and when
you need it to brake
and slow you down, it's
going to offer you that.
Having that sort of edge
on a low stack height tire
is really important to your handling of it
because it enables you
to have massive grip
for something that really
doesn't have a lot of tread
by all accounts.
Sipes is something you're going to see
on a lot of aggressive tires
and a lot more modern tires.
This one in particular
is covered in sipes,
that is these three markings
seen on each of the lugs.
And they have a very specific job to do.
Now, imagine a big lug like this one
on the shoulder here, if this had no sipes
then it'd be quite a solid lump of rubber,
it's not going to move around
rocks and things like that.
By putting the sipes in it,
all these little slices,
you can tailor the way
it actually manipulates itself over rocks.
And then by having progressive sipes,
again, you can change the
characteristics again.
If you look at these central
knobbles here, for example,
they've got three sipes on each one
and they're progressive,
i.e., the bigger one
is at the rear towards me,
the smaller one is to the front.
Now you want this tire to cut in
and give you traction
when rolling forwards
but you also want it to roll fast.
So by having a smaller sipe further away
from that leading edge, it
enables it to roll faster
and it gives you a proper edge
to claw into that terrain.
By having a bigger sipe at the rear of it,
on the trailing edge, that
is the edge for braking.
So that's basically going to deform loads
and give you loads of grip
and stability under braking.
It's really clever stuff,
and if you actually look
at a tire in detail,
you can work out what those sipes
are going to do on cornering.
Of course, you want those side knobbles,
you want them to deform,
you want them to move around and stuff,
because otherwise it's just
going to scratch around for grip.
Whole point of the tire is it's malleable
and deforms to the surface
while still giving you
that predictability.
Sipes are very clever.
If you're riding, for example,
in loose conditions or mud,
then you're going to want some
sort of open tread design.
Now, a design like this is great,
it's got a very high
stack height of the knobs
which means there's a lot to stick in
and give you purchase on the ground.
And there's a lot of
gap around all of those.
That means it's basically
got loads of room
to do its job, it also means
it's not going to hold onto that mud.
If the knobbles are real close together
and you're riding in thick, sticky mud,
it's going to clog the tire up
and it's going to become overcome,
it's not going to give
you any more traction
once it becomes a solid unit.
The whole point of these is
that they can always cut in,
there's always something there.
Because of how aggressive these tires are,
they're actually favored by riders
that want to ride in lots
of other conditions as well.
I know for example, Blake loves this tire.
The downside with a tire like this
that you might not
consider, even with thick,
heavy duty, endruo casing on,
there's a lot of casing
here that's exposed.
Ideally, if you're riding somewhere,
let's say, the Megavalanche,
you probably wouldn't
want to run this tire
'cause you want to maximize on
the casing protection you have.
This is going to be
amazing in terms of grip
and predictability, but
all you need is one slice
that's going to really
ruin your day riding.
You'd be much better off, for example,
on what looks at a glance
like a similar tire,
except the knobbles are just
that bit closer together.
There's a lot more knobbles
in the same sort of surface area,
you see here, so therefore
this is a much better choice
to use in rockier terrain.
It also means there's
a lot more edges here.
When you're riding rocky terrain,
everything's moving around,
you're going to get a bit
more of a predictable ride
if you're riding with a tire like this.
Now, rubber is the last
piece of the puzzle,
despite it being what the
tire's actually made from.
Because of the fact there's lots of
different compounds of rubber available.
Now, rubber tire compounds are measured
using the Shore durometer.
You can get these little
durometer testers,
I've used one before in a factory visit,
this is actually a digital
one that I had before that.
It enables you to measure how firm
the compound of the rubber is.
Now, a higher number like 60A for example,
is going to be far more durable,
and it's going to roll faster,
but you're going to have
less grip as a downside.
And you get the complete opposite
with a lower number, let's just say 42A.
You're going to get much more grip,
much more sort of compliance
of the rubber itself,
it's going to deform around obstacles,
but as a result it's
going to be much slower
because of all that extra grip,
and it's actually going to
wear out faster as well.
Now, back in the day, used to buy tires
by the rubber number.
Maxxis, for example, you could buy them
in 60A, you could buy them in 42A,
you could buy them in 40A.
Used to buy them in numbers, but,
unless you knew exactly what those were,
it could be quite confusing,
so most manufacturers now
have settled on their own
identification system.
For example, Continental use BlackChili,
Schwalbe use their ADDIX system,
and I think they have four
different models within that
ranging from fast to extremely grippy.
Maxxis no longer use the
actual durometer ratings
and numbers, they instead refer to theirs
as Maxx Grip, or Maxx
Terra, or Maxx Speed.
Now, everyone is different and they have
their own different things available
to you as a consumer.
Vittoria are quite different, though,
they actually, in addition to offering
a single compound, twin,
and triple compounds,
they actually are the only manufacturer
that can offer you a quadruple compound.
So, a four C compound tire.
They've got the only machine in the world
that can extrude four
compounds into a single tire.
And with the testing they've done,
they actually find the
four compounds works best
across most of their tires.
So you might get a cross country tire
that's got four compounds in it
and you might get the enduro race tire.
It won't necessarily be
the same four compounds.
Of course, on a cross country race tire,
the shoulders might be slightly softer,
the center tread might be slightly harder
but it's going to be nothing
compared to the enduro tire.
Now, if I take this Shore
rubber durometer tester
and I just test it out on
the sidewall of this tire,
bearing in mind that these
aren't going to be super accurate
unless you use it on a block of rubber,
it's quite difficult to do
and get an accurate reading,
but these side knobs here are quite big.
So I'm going to do a
measurement of the base
and a measurement of the top,
and it should have two different readings.
Now, let's see, if I look down here.
I'm getting about 56, 56 to 58.
Now, obviously, that's quite
firm, quite supportive.
And then if I take that and measure
right at the top of the
knobble there, 41.5, about 42.
So that's a very soft compound on the top
but much harder and more
supportive underneath.
Just to give you an
idea of how that works.
And the last thing to reference as well,
you might've seen graphene
written on the sidewall of these tires.
Graphene is a graphite derivative
and it's kind of like
the wonder stuff, really.
Now, I actually went to their factory
and found out a bit about this stuff.
So, graphene is the thinnest
known material to man,
it's also the strongest,
and it's the most conductive
material known to man.
Just to give you an idea of this, right,
so a human hair is 0.070 of a millimeter,
a strand of graphene is
a million times thinner.
A million times thinner than
that, can you imagine that?
It's absolutely crazy.
And so, graphene is essentially
used on a molecular level
in Vittoria tires to fill in the gaps
in the way that rubber is used.
So if you think what that means,
it is essentially, you're going
to get some abrasion resistance
because the material
is stronger than steel,
it is very very tough and resistant.
It's also going to help resist
them wearing down so far
so, although soft compound
rubber on the tops of tires
you see tends to wear fast,
the graphene actually counters that.
There's also an added benefit
that they didn't foresee, though,
is that graphene actually
gives all of the tires
very much enhanced
performance in wet terrain.
Pretty insane technology, that.
Well, there you go,
there's quite a lot more
to a set of tires than
you might have thought.
There's loads in the casing,
there's loads in the rubber compound,
the tread, the sipes,
all that sort of stuff.
In fact, one of the
coolest things I've done
on GMBN Tech was visiting a tire factory
and actually seeing
how they make the tires
by taking the rubber
straight from the tree
and turning it into a finished tire.
Honestly, fascinating stuff,
please check that video
out if you haven't already,
and thanks for hanging
around, see you later, guys.
