- Mountain bikes have a lot of technical things going on.
Got hydraulic brakes, you've got moving bearings,
in the form of headsets, bottom brackets,
rotational bearings with your wheel hubs.
You've got shock absorbers, you've got pivots.
There are loads of things going on.
And for that reason, it can be quite easy
to misdiagnose problems.
Or even simply misunderstand things,
especially when marketing terms
can be quite confusing at times.
So I'm going to break down some of these
and put them to bed right now.
(relaxed electronic music)
Okay, first up is actually more of a problem,
so this is when your headset feels loose,
but it actually isn't.
So your headset, of course, are the bearings
that are housed in the head tube of the bike,
they're responsible for your steering.
If your bearings are loose,
that means things can rattle around,
that is not good.
If your bearings are tight, of course,
the bearings are being constricted
and your steering will be very heavy,
almost index sometimes,
you can actually feel the notches of the bearings.
Again, not good.
What you're looking for
is the bearing to be preloaded nicely
so it spins without hindrance or movement
and it does its job with no movement.
Now, there are a lot of things that can cause movement
on the bike that can feel like a loose headset.
When in fact, your headset is not the problem.
The first one might be the bushings
on the inside of your fork.
Now, forks are telescopic design,
it has an outer leg and has an inner leg
and of course, they slide on bushings.
Now, if those bushings are older or worn,
or even, in fact, on a new fork,
there's going to be an element
of fore and after flex or movement.
It'll be a minute amount.
The older the fork gets, the more notch-y that's going to feel.
Now, a good way of feeling
if it is this part of the bike
is putting the front brake on,
have your bike on the ground,
and you can feel if the headset's lose
by moving it backwards and forwards.
You'll actually feel some movement
on the top or the bottom here.
But also you can do the same at the fork,
if you just put your hand around it,
now say you're doing it like this
rather than leaning on the bike
because the second you lean on the bike and do it,
you can actually compress the fork
and that can add another thing in that can be confusing.
So you may get a little bit of play here,
a very small amount isn't really a problem,
there has to be an amount of movement there
in order for them to move up and down,
otherwise there'd be too much binding going on.
Now, of course, if there's a lot of movement
then perhaps you want to get on the phone
to a local bike shop or your local suspension tuner
because you may need a proper fork service.
Now, something else that's a characteristic thing
that it can be, would be your actual wheel axle
is not completely tight.
Of course, that sends alarm bells ringing
with safety, so definitely check this.
If you have an Allen key bolt,
do it up to the correct torque setting.
If you have any form of quick-release lever,
anything like that, make sure it's in the position
that is marked as safe for that style unit.
There's various different ones,
and they all come with a little tag
just to let you know that.
Now, onto more of a safety one.
Make sure your caliper bolts are tightened up properly,
and I do recommend using some sort of thread lock
on those threads to make sure they can't rattle loose.
Remember, these are just bolts,
they're not invincible on a bike,
it's not the fault of a component
if a bolt comes loose, but it's entirely possible
for a bolt to come loose in the off-road environment.
However, there is still one more thing it could be.
And this is something that is always missed by people.
And that is your actual brake pads moving around minutely
inside the actual brake unit itself.
If you can see here,
I'm just moving the bike very very slowly
and you'll see the fins on the pads
moving a very small amount.
Sometimes they can rattle,
sometimes you can feel this in the headset
and it will make it feel as if your headset is loose.
So, just because your headset feels loose,
it doesn't necessarily mean it is.
Okay, next up.
This one's a bit more of a rubbish myth, to be honest.
Long bikes don't go around corners.
Utter rubbish.
I ride long bikes, I've ridden much longer bikes,
Henry's got a ridiculously long bike at the moment,
and so has Rich over on GMBN,
and they can get round corners just fine.
You just have to recalibrate the way you think
about approaching the turn.
Now, this is nothing technical on a bike thing,
a long wheelbase bike will get round the same turn
that a short wheelbase bike will,
you just have to ride it a bit differently.
Think of the difference of, perhaps, I don't know,
a compact car like a VW Polo,
and a long wheelbase Transit van.
Yeah, alright, so you first get in your Transit van,
you might feel a bit like, oh God,
never going to get round there.
You just have to think about it,
you have to maybe swing out a little early
in order to get your rear wheels comfortably
around that turn, it's just the same
on a long wheelbase bike,
you just have to rethink how you ride.
And to a degree, a long wheelbase mountain bike
will actually make the most of a turn
as opposed to a short wheelbase bike
where you could actually ride,
the correct line might be round the outside
using some of that, it might be round the inside
but because of the fact you can take that inside line
all the time, you might end up
actually just defaulting to that
whereas the longer bike is actually going to force you
to come out wide and give yourself more space.
More space means a quicker exit,
so, technically, it could be better.
Now this one always makes me chuckle,
dry lube isn't actually dry.
Yeah, believe it or not, there are two main types of lube,
there's lots of subcategories,
we're just going to look at wet lube and dry lube here.
Now, both of them are liquid based.
One is a wet lube, it's designed for wet conditions,
one is a dry lube and is designed for dry conditions.
Now, the fundamental differences between them are,
the wet lube is a much thicker, more viscous liquid.
The idea of that is, it's very water repellent
and when you put it on your chain, it stays in place.
The lubricating particles get into the chain
and they stay there.
The downside is muck and grit can stick to it.
However, if you're riding in wet conditions,
you need that protection,
you need that constant lubrication.
So you'll need a wet lube.
A dry lubricant however, the actual wet bit
in a dry lube is not the lubricant,
that is just a solvent carrier.
That is just designed for application,
to get those lubricating particles
into the rollers and the pins of the chain
and then they'll evaporate, hence, leaving it
as a dry lubricant afterwards.
So other stuff doesn't stick to the chain.
So if you just see here, I'm pouring a wet lube
and a dry lube on a worktop, and yeah, they look wet.
But one is wet and one isn't.
(upbeat rock music)
Okay, another golden one here.
27.5 inch wheels are not in fact actually 27.5.
Yeah, that's right.
The correct measurement, technically, on paper,
is 650 B, which is a French measurement.
Okay, so we're well familiar with 26 inch wheels
and this is roughly how it works.
A 26 inch wheel is actually about 22 inch.
You've got to add onto that a couple of inches
on either side for your tire.
The 26 refers to the outside diameter of a wheel
with a typical tire on it.
29 inch, of course, you know where we're going with that.
27.5 actually is nearer to a 26 inch wheel
than it is to a 29 inch wheel.
A 26 inch wheel will actually be a 559 millimeter rim.
So that's actually 22 inches, not the 26.
Obviously you got to add in the tire sizes
to make it 26.
The 27.5 is actually 584 millimeters.
That's only 23 inch, so it doesn't really sit in the middle
of the two wheel sizes, 26 and the 29.
So 591 millimeters would be exactly in the middle
of 559 and 622, which is 29 inch.
Confused?
Yeah, it's one of those things.
And if you're wondering why this happened,
650 was actually around many years ago,
the B refers to the tire itself,
the 650 is the outside measurement.
It was always there, and actually we just repurposed it
for use on mountain bikes,
and it ended up being roughly in the middle
of 26 and 29 inch wheels.
And that's why the industry decided it was easier
to refer to them as 27.5 for argument's sake.
Because having 26 inch,
you're talking the whole metric, imperial thing,
it's a bit confusing, 26, 650 B, and 29,
doesn't really sound right.
26, 27.5, and 29 is much better.
But there you go, 27.5 isn't actually 27.5,
it is nearly 27.5.
(relaxed electronic music)
Okay, now, something we often hear people talk about is,
why does my chain come off when I pedal backwards?
Now, the purists out there might just say,
well, you should be pedaling forwards
'cause that's what you do on a bike.
However, there are occasions
where you might want to just go half a revolution backwards
and if your chain comes off, that can be a problem.
Now, the instant solution around this sort of thing
might be just to put a chain guide on the front.
And that might sort the problem, but,
there are a few reasons this can happen.
Now, there's no need to think your bike is broken, it's not.
Sometimes this does just happen on bikes.
The prime version of that would be
if you have multiple chain rings
on the front of your bike.
If you have a double or a triple setup,
the combination of crossing gears
means your chainline will not be perfect.
It might be okay pedaling forward
but because of the shifting ramps on those chain rings
and to a degree, on the cassette at the rear,
sometimes your chain will actually derail
when you pedal backwards.
The straighter in line, by big to small,
or middle to middle, or small to big,
you can get, the least likelihood that is of happening.
Of course, it's going to be very different
on each independent bike.
And then of course, there's the actual chainline
which refers to the length of the bottom bracket,
how your chain rings actually line up with your sprockets.
On a modern one-by bike, like my one here,
you'll see that the chain ring lines up
almost completely central with the rear sprockets
on the back of the bike.
Now, because of that, the chainline is actually very good
on both the lowest and the highest gear,
it's designed to be used in all of those gears.
Now, I can pedal backwards in any one of those gears
and my chain will not come off.
Of course, there might be exceptions to this again.
And those exceptions might be
you've got a filthy transmission.
So, perhaps your chain might be a bit gunked up
and it's hooking up, or perhaps your guide wheels,
also known as the jockey wheels,
perhaps they're not rotating properly
and the chain actually derails off those
which in turn would put it off
at the bottom of the chain ring.
There are a few different ways it can happen.
Most of which can be traced back to
a very specific thing.
If you just spend a bit of time looking at it,
it's not necessarily your bike's fault.
Obviously, you're not supposed to pedal backwards,
they're not designed to be pedaled backwards.
However, you should be able to pedal backwards
without the chain coming off.
So, it's usually one of those things.
Short stems are best, like that one.
Well yeah, kind of.
They are kind of the best, but also,
you can't just put a short stem on a bike
and expect that bike to handle well.
If your bike is a short bike
and you put a shorter stem on it
than it was designed for,
arguably, you're going to either ruin the handling
or you're going to ruin the fit of the bike
as you ride it, and neither of which are a good thing.
Likewise, you can't just go the other way round,
you couldn't just put a long stem
to make a short bike fit you,
because you're going to mess up the handling.
The whole balance of the bike isn't going to work.
This bike, for example, actually came out of the box
with a 50 millimeter stem on it,
it was designed for that length.
I've got, by nature, quite a short upper body
but really long arms.
That's why I run a full width bar
and I run a slightly shorter stem,
that's a 35 millimeter.
But it kind of works out for me,
it doesn't disrupt the handling of the bike.
The bike is nice and long,
there's a really long reach on this bike
so I don't have to worry about compromising position
when I'm stood up out the saddle climbing, for example
or ever seated, it works just right as it is.
For example, my Canyon Lux, that's a cross-country bike.
That's got an 80 millimeter stem,
I've got almost a negative rise, it's flipped.
And that's a very long stem compared to this 35 mil stem
but it's the correct length stem for that bike.
It's the correct stem for the fit of the bike
and for the way the bike is intended to be ridden.
And you can see that I'm riding it just fine here.
It's, of course, a cross-country bike,
it's not supposed to be jumped and hammered around,
by putting a short stem on it,
you're kind of changing
what the bike's intentions actually are.
So, whilst a short stem may make certain bikes handle well,
it's going to make others handle really badly.
Coil shocks are better than air.
Well, that's, (he scoffs)
where do we go with this, where do we even start?
Yeah, I've got a coil shock on here at the moment,
I'm actually in the middle of
trying to find that out myself.
But there's a load of factors that go into this.
For example, does your weight vary
when you're riding a bike?
Say, if you're a photographer
and you ride with a heavy camera back one day
and the other day you don't,
an air shock will probably be better for you.
Because of the fact you can instantly adjust it
to your weight immediately.
With a coil shock, you're stuck
with that coil spring on there.
In which case, you have to take it off,
you have to take the spring off each time
to change the spring rate, that's no good.
And of course, you also have to factor in
the most important thing of the difference,
is the suspension curve at the back end of your bike.
There's three main traits you get,
I'm not going to get into all the leverage
and all the stuff on bikes,
but you'll get a falling rate design,
a linear rate design, and a rising rate design.
A rising rate design will work really well
with a coil shock.
A linear rate, or a falling rate,
will not work very well with a coil shock.
The reason for that, coil shocks by nature
are very linear in action,
an air shock is very progressive by action.
It's that simple really.
One is not better than the other.
You might prefer one, and one might suit certain bikes more,
but there's no real better question there.
On the upside, coil does offer an amazing feeling.
It's really really sensitive,
really good for small bumps and stuff,
however, that in itself can be very different to riding air.
Air, you're very connected to the ground,
you can feel it, coil, sometimes,
I think it's a bit like punching smoke.
You can feel a little bit disconnected.
But that might be right up your street.
Oh, and of course, the last thing is,
how you actually ride.
Coil shocks and coil forks, by nature,
are really good in rough terrain,
if you like plowing through stuff,
they're going to feel great.
But if, like me you to dance around a bit on the trail,
maybe jump things and push into backsides,
air shocks might feel better for you
because there's a bit more support.
And they allow that agile style of riding,
they're two very different styles
and neither one will actually suit all riders,
so you have to pick what's best for you.
And the last one, shock or fork lock out,
you need it to go faster uphill.
Not really, no.
How you pedal is actually how you're going to go faster uphill.
Of course, there are some factors that go into this.
If your bike, for example, doesn't have much anti-squat,
when you pedal it's going to mean
you're going to bob around a bit going up the hill.
So although it's not going to make it go any faster
by having a lock out on there,
it's definitely going to be a lot more comfortable.
And that might make your perceived reaction be
that you're actually going faster
or it's slightly easier.
But be surprised, the actual difference
is not much in there.
For fork, again, of course, you can lock them out,
you can keep them open, it's entirely up to you
but really, it doesn't change
how the bike is actually going to ride.
Honestly, if you're looking at this
as an excuse to buy more kit, you don't need it.
You can set your bike up accordingly,
you can run it a bit firmer if you needed to,
you could perfect spinning circles on the pedals,
going a slightly higher cadence
rather than just mashing those gears.
Of course, as you mash through gears,
naturally you use more body weight
so the bike's going to bob up and down more.
If you're spinning nice and neatly like a roadie,
you're doing very little in disturbing the bike.
So, don't think of it as you need to try new stuff
on your bike all the time,
sometimes you might just need to fine-tune
what you're doing on the bike to go faster.
Well, there you do, there's a few prime candidates there.
In fact, another prime candidate
would be buying a bike by looking at a geometry chart.
Now, you might know your numbers,
but do you know your numbers
in combination to the dynamic geometry of the bike?
How those things might change
if your bike has high anti-squat?
No, it changes everything!
So don't buy a bike by looking at a geometry chart,
buy a bike by demoing the bike.
That's how you want to be doing it
'cause you'll truly feel what the bike feels like.
If I've missed any, let us know
if there's any other sort of conceptions
that are bad communication, misunderstandings
in tech stuff on bikes that we'll pick up in another video.
Cheers for hanging around,
don't forget to subscribe, cheers, guys!