Mountain Bike Rear Suspension Set Up Ep. 7 | GMBN MTB Essentials

Mountain Bike Rear Suspension Set Up Ep. 7 | GMBN MTB Essentials


– This is the GMBN Tech Essentials series. Our easy to follow guide to maintaining and setting things up on your bike. This particular video
is all about setting up the sag on your rear suspension,
and dialing everything in. Something which is
actually very simple to do, provided you follow a few simple rules, and you know a little
bit about the equipment on your bike. Here’s how you do it. (theme electronic jingle) (hip hop beats) Now firstly, let’s talk a little bit about the equipment on your bike. So, you can have some kind of
shock absorber on your bike. Now, the common options out there tend to be made by Fox and Rockshox. But there are many different
brands available on the market. And fundamentally, the air
shocks all work in the same, and they all have very similar features. So, there are two main
types of shock as well. There’s a coil sprung shock,
and an air sprung shock. The main difference is
on a coil sprung shot you simply have a round
coil spring on the outsides which supports your body weight. The internals of the
shock, they’re all there to deal with the damping and the right characteristics of that shock. Now with a coil sprung
shock you’re limited in when you set them up to the
actual spring that’s on there. So, you have to have the correct spring to correlate to your body weight. Now let’s take a look at a few details on a actual air shock here. So, I’ve got a Rockshox
Super Deluxe in my hand, but like I said the basics are
the same on most air shocks. So, you gonna have an air valve. This is a schrader valve
or a car-type valve. This is simply where you
inflate the air into the shock to get it sprung to your body weight. Nice and simple. Then on the actual shaft part of the shock you’ll find that most shocks will have an O-ring on there, a
little rubber O-ring. You can use this to monitor
how much sag you have. And the sag, crucially,
is the main adjustment you need to set on any air shock. Sag, simply put, is how
much the shock moves and compresses when you
are set on the bike. The effect of that is it
allows the shock to extend and the wheel to fill
the wholes in the ground, as well as, compress and
absorb bigger impacts. So, it’s a very important
setup point to have. Now you might notice this shock also has a secondary chamber on here. This is called the piggy-back. Now you don’t have this on all shocks, and don’t worry if don’t on yours. This is just for
additional damping support. So, you tend to have this
on more advanced shocks. But if we just pretend that’s not there, and we’re talking simply put, you have the main air can and you
have the sliding tube that you measure your sag against. Nice and simple. There’s also the eye lids
at both ends of the shock. This is where it’s mounted onto the frame. And quite often you’ll hear a shock referred to in eye-to-eye length. The shock’s stroke length
is the length of travel it has on the exposed shaft, right here. Very simple. Now, all rear shocks will have some kind of rebound adjustment that is controlling the rate at which the shock extends after an impact. Now this is another
crucial thing to set up. Now you might also find on your shock, there might also be a lever
or an additional dial. Now this is for adjusting the compression. Now most riders will be familiar with this for the term lockout. Simply put, if you turn
this lever all the way to this way, in fact, there’s
a little icon on there to suggest the padlock is locked. That effectively locks out the shock. So, that means it’s not gonna operate under your body weight. Which means it’s gonna be very efficient for riding uphills or road sections. Anywhere where you don’t want
the shock to be operating, and then when you hit
the off-road section, or your descending
sections you can open it up and the shock opens up
and feels very nice. But essentially the
common rule is compression tends to be blue, and
rebound tends to be red. Now the information
we’re about to give you is very general and applies
to all shocks on the market. But if you wanna be a bit more specific to your actual shock. It’s worth checking your
manufacturer’s website. Now when you do this they’re
gonna recommend base settings. So there’s gonna be air pressure settings in order to set the shock to
your approximate body weight. And they’ll do that in percentages
of the travel available, which we’ll get to in a minute. The other one they’re gonna
refer to is how many clicks or turns a rebound in
compression you might wanna have to get started on your bike. Some manufacturers will
refer to their compression and rebound settings from fully open. And some will refer to
it from fully closed. So what exactly do you need to
do in order to set your sag. Well, first up if you have an air shock, you’re gonna need a shock pump. You cannot do this without that. If you don’t have an
air shock and you have a coil spring on your bike, you might wanna have a tape measure. And I’ll show you why when we get to it. Of course you’re gonna need a shock of course on your bike. If you’ve got hardtail there’s
no point even doing this. (bicycle gears spin) Now something that’s
very important to note with any type of rear
shock absorber is the fact your body weight is affected by what you carry when you ride. So, therefore it’s
recommended when you set your sag up to do this wearing all the kit you’re likely to wear
when you go for a ride. That means a hydration
pack if you carry one. Fill up with water with
the amount of water that you’re likely to carry with you. Phones, tools, helmet,
all that sort of stuff, because it does make a big difference to how your bike will feel on the trail. (jingle) So, first thing you need
to do just before you get going with setting up
your sag on the bike is understand sag, and also make
sure your shock is prepared. So, if you have a lockout on there, make sure it is fully
open before you do this. If you have any sort of
clam switch on your shock make sure that is fully open. And if you have any compression dials make sure they’re unwound. As explained at the beginning of the video the reason you set up sag on there is to now enable the
shock to let the wheel track the ground properly. Now if you have too much
sag it’s gonna feel wallowy, if you don’t have enough
it’s gonna feel harsh. Now the typical amounts
vary between 20 and 30% sag. This is what manufactures recommend. But it does vary on your preferences. If you have a long travel
bike I will probably air on a slightly less sag to start with. And likewise if you have
a short travel bike, I’d air ’em sightly
more just to start with. But this is personal preference. So, for example, Rockshox with a DebonAir air sleave on there. They recommend 30% sag,
where as with the Solo air they recommend 20 % of sag. These are all specifics to your shock, but the general rule of thumb, 20-30% sag, or the way you like it.
(jingle) Now, the typical rule of thumb
is putting your body weight in as air pressure. So, I’m 200 pounds and I’m gonna start by putting 200 pounds of air into this Fox Shox that’s on my bike. Now the same applies
to Rockshox, 200 pounds in body weight equates
to your base setting of 200 pounds in air. Now this will vary
depending on the suspension that’s on your bike. So, you’ll start at this point you might need to release some air, you might need to add some more air. It’s that simple. But something you need to
know about different shocks it’s about the equalization process. Now with Rockshox you need
to be pumping the shock up to 100PSI first, then you
need to compress the shock 5 times to about 50% of the travel. That enables some of the air
to go from the main chamber into the negative chamber. The reason for this is so the positive and negative air chambers inside the shock can equalize. Then you can continue
to inflate from there. But with the Fox Shox, like
this one on my bike here, gonna inflate it to my bodyweight and then with the shock
still in place compress it about 10 times to that 25% of the travel, and then this will equalize those positive and negative air chambers. That’s the general rule of
thumb between the two systems. Now at this point, this is when
it’s handy to have a friend. If you haven’t got a surface you can balance up next to, because they can hold the handle bars of your
bike to keep you up right. I’m balancing just on the bench here. I’m set on the bike. Now what you need to do
in order to set your sag, and I’m looking for 30% in this case is to bounce up and down
a few times on the seat. This will just break the stichion in the seal of the shock there. And then set that O-ring. So, pull the O-ring up against
wiper seal, just like this. And then very carefully
try not to disturb it. Take your body weight off the bike. So, get off the bike,
and then that will be the sag that you’ve just set. Now, what you’re looking
for is 30%, in this case of the available shaft travel. Now some shocks like this
Rockshox one on screen right now, will have indicators on the shaft itself. Other shocks like the
one I’m using on my bike don’t have that. Now in this particular
case for about 30% sag I’m looking at 16.5
millimeters of sag here. So, that is the difference between the seal it self and the O-ring. So, I’m just about on that now. And actually I’m happy with that. Now when you’re set up if
you’re running slightly firmer or slightly softer than this, simply repeat with the air
shock until you get there. Now, when you’re measuring a coil shock it’s a little bit different,
because you don’t quite have access to the shaft on the
shock in the same way you do with the exposed shaft on an air shock. So, ideally the easiest way to do this is measure the distance
between the two eye lids of the shock there to
get the total length. And then basically you can
work out the percentage of sag in relation to the amount of travel that that shock has. In a similar way that
you worked out the sag on this Fox Air Shox that I’ve just done, you can do the same, but
instead of measuring it by looking at the O-ring
on the actual shock itself, you have to simply measure
the eye-to-eye distance as you sit on the bike. And hopefully you’re gonna
be within that 30% area. If you’re not, this is
where things can get tricky. On coil shocks you only have
two turns of the preload ring to adjust and compensate for
that in either direction. Any more than that and
you’re gonna need to change the spring rate of either a heavier spring or a lighter spring. Coil springs come in
very different weights. They all come between
fifty pound increments, but when it’s a fine measurement you’re gonna need to
go 25 pound increment. You’d only really get
these between 400 pounds and 500 pound springs. So, it can be quite tricky
to get the shock just right. If you aren’t able to measure between the two eye lids on a shock because of the strange frame design, for example, it’s not the easiest on
Blake’s particular bike here. Another way to do this is
to do this by wheel travel. So, Blake’s bike is a Scott Gambler. It has 210 millimeters
of rear wheel travel. Now if you measure the distance between the back of the
saddle and the wheel, when you sit on the bike the amount of sag to get a 30% on this
bike is 67 millimeters. So, if you deduct the 67 millimeters from that distance between the tire and the saddle you can work out that that’s the 30% sag. Again, it does depend on
the settings on the bike. Blake does like his
bikes to feel quite firm, other people might want
them to ride about 40% sag on a bike with this much travel. Now once you have the
sag set up on your bike in a area that you’re looking for, the next thing to adjust is the rebound. So, again, that is the rate at which the shock extends to its full length. So, what you’re looking
for is a happy medium between something that’s
fast enough to react to bumps on the trail, but slow enough to keep everything under control. If it’s too fast it will
feel like a pogo stick and out of control. If it feels to slow it’s
gonna feel really harsh, and over damped. Now, most manufacturers
offer a handy chart with base settings to start
from, just like the air ratings according to body weight. So, it’s just a few examples floating by on screen now, just so you can get this. And a really helpful guide to start with. Now on the shock I have
on my Nukeproof here is a little bit more advanced. You have to use an Allen key to adjust it, and there’s actually two settings. But there are base settings
on the website for it. Then this Rockshox one
is really simplified, Tortoise and the Hare. Very, very simple to set up. Experiment with this and
see what feels best for you. And the compression
adjustment on the shock, really that is more of a convenience on most shock absorbers. The reason you would have this is simply to make the bike climb a little bit nicer. Is nothing to do with
the set up on your bike as far as the suspension design goes. It’s more when you’re
climbing you’re body weight is moving around, and
by using that lockout you stabilize the bike. So, it climbs a lot more efficiently. So, have a little play
with that out on the trail. Just make sure when you
hit all the fun stuff you unlock it to maximize on all that nice shock absorbing travel you have. (bicycle gears spin) So, there we go. It’s that simple. Just take your time and
you’ll get it right. If you’re unsure get a friend to help you. Can make it a little bit
easier to do this process. For a couple more videos click down here for our
Essentials playlist. It has all of the other
videos in this series. And if you wanna find out how to set up your suspension fork
in exactly the same way as what we’ve just walked you
through, click up top there. As always, please continue
to give us thumbs-up for all our videos on GMBN Tech. And if you haven’t already done so, click that subscribe button.