Speaker 1: 1x drivetrain. We first saw them on mountain bikes and then on
specialist applications like cyclo-cross and TT bikes and then increasingly on adventure
gravel and all-rounder bikes such as this Orbea Terra. What do you need to know in
order to set up a 1x drivetrain correctly? In this video, we're going to show you. [music]
When it comes to setting up a single ring 1x groupset, many of the steps are exactly the
same as a regular group set especially the shifters, the bottom bracket, the chainset,
and the brake setup. Where it tends to differ is the rear mech and that's what we're going
to focus on. We're also going to explain some of the nuances between Shimano, SRAM and Campagnolo.
First up, these are the tools that we would recommend for the job. Allen keys, a t25 Torx key,
a torque wrench so that you can get everything torqued up correctly,
cable cutters and a chain splitter. Bonus tools would be quick link pliers and a quick link for
your chain. I'm going to explain some of the key differences between a 1x groupset like this and
a normal 2x or even 3x groupset as this will help when you start maintaining it if you understand it
a bit better. The most obvious difference is the fact that you only have one chainring at the front
instead of two or three. This makes the system much easier to set up because you don't have
to mess about with a front derailleur. It does mean though that you need to pay
particular attention to the chain tension and the chain length. As you don't have a front derailleur
to hold that chain and guide it in place, it can mean it's easier to drop it when you're traveling
over rough terrain or in cyclocross situations if it's not set up correctly. You also have a special
chainring on the front with narrow-wide teeth on there and this also helps keep the chain in place
in those rough situations. Another reason can be weight. It's for this reason that I've sometimes
seen specialist hill climb bikes run a 1x setup in a bid to save precious grams. Generally, I find
that there isn't actually that big a difference in weight between most conventional 1x and 2x setups.
That's because although you do save weight by removing a chainring from the front,
you reintroduce weight into the system by having to use this massive cassette
at the back to get the same or equivalent spread of gears. Also, the rear mech is more
substantial and this adds more weight as well. Although you do remove the shifter gubbins out of
the left-hand shifter, that doesn't actually weigh that much. The difference between equivalent level
Ultegra 2x system and a 1x system such as this GRX isn't actually much at all. Another key difference
is the use of stabilizers or clutches on the rear derailleurs. The idea behind these is that when
they're engaged, they increase the amount of force required to pull that cage on the rear derailleur
forwards and make the chain slack. By doing this, you can maintain a tighter chain when going over
rough terrain, and again, there's less risk of it dropping off or slapping around on the chainstay.
SRAM pioneered this technology with the use of clutches. They now call them orbital stabilizers.
They also have their cage lock system which you can engage to lock the rear derailleur which helps
insertion and removal of your rear wheel more easily and keeps the derailleur out of the way.
Shimano such as this GRX has a clutch lever that you can turn on and off. The new
Campagnolo e-car also has a clutch built into it too with a cage lock system as well. Now,
for those of you interested in perhaps bodging a 1x system or maybe a hill climb bike or a time
trial bike then you can do it but it will be a bodge. The main issues you've got is if you don't
use a narrow-wide chainring with the longer teeth like we see here, there's a much greater risk
that you will drop the chain without that front derailleur there. Also, many rear derailleurs
can work as a bodged 1x setup but if they're not specifically designed to do so, then they will be
less efficient in terms of chain line efficiency throughout the whole range of the cassette.
Installation of a single ring chainset is the same as installation of a double or triple chainset.
We'll assume you've got that in place. We'll also make the assumption that you've fitted
your shifters and set up your brakes and got your shifting cable ready to be connected to
the rear derailleur. If you're unsure of how to do any of these jobs, then fear not because we
do have videos that go into more detail on all those specific jobs as it would make this one
video too big if we included all of them here. It also takes into account people who might have
different braking systems such as hydraulic disc brakes as we have here or perhaps rim brakes as
they can also be found on 1x groupsets. If you are routing cables internally, one thing I would
highly recommend though is to use a routing kit. This is literally the best thing in the world.
First, we're going to attach the rear derailleur and they attach much the same as a normal rear
derailleur but it's important to make sure that the clutch or lockout isn't engaged. On Shimano
rear derailleurs, we turn this lever down to turn the clutch off, and SRAM and Campagnolo have a
push-button lockout. Next, we're going to bolt the rear derailleur onto the mech hanger here using a
5-mil Allen key. Note this little lip here on the hanger. That is what the B-limit-screw will press
against. [music] Next, you need to make sure the cable is pulled all the way through and that the
head of the cable is properly locked and secured in the end of the shifter. Then you want to shift
the shifter so that it goes in the smallest cog on the cassette. With your cable threaded
through the guide, we're next going to install this little bit of cable housing on the end.
Then we're going to thread the cable firstly through the barrel adjuster
on the rear derailleur. With the cable through the barrel adjuster, we then thread it through the
pinch bolt and clamp it in place. Also, if you're using a Shimano GRX rear derailleur like this,
the bit of exposed cable between the barrel adjuster and the pinch bolt is covered by
this little rubber housing to help protect it. We're going to thread that on first. [music]
As an aside, pliers can also be really useful at grabbing hold of the cable and helping you pull it
all the way through. When it comes to adjusting the angle of a Shimano 1x rear derailleur,
it's not too dissimilar from a standard rear derailleur but you will want to pay
more attention to the B-limit-screw as this will have a greater bearing on the overall shifting.
As you shift up the cassette, and this is unique to 1x rear derailleurs, you'll need to make sure
that that top jockey wheel has enough clearance for the next gear so that it's not catching on it.
Now, to do this you adjust the B-limit-screw. You turn it anti-clockwise to decrease the gap
and clockwise to increase the gap. Usually, this is done with a 2-millimeter Allen key.
Next, we need to set the high and low limits on the rear derailleur. The limit screws limit
the amount of movement that the rear derailleur can travel laterally. Therefore, it stops the
rear derailleur coming too far out which would drag the chain potentially
off the cassette and then into the stays here and damage your frame
or too far the other way and drag the chain into the spokes and potentially damage your wheel.
We're first going to adjust the high limit screw which controls the movement on the bottom of the
cassette. The smallest sprocket. What we're looking to do is to get that top jockey wheel
perfectly in line with that smallest cassette cog. To do so, you can turn
this limit screw with the 2-millimeter Allen key. This is best done sitting behind it so that you
can see that it's perfectly in line. You next want to repeat the process for the low limit screw by
shifting the rear derailleur into the easiest sprocket, the largest sprocket on the cassette,
and then turning the low limit screw clockwise and anti-clockwise to adjust it. Top tip, if you're
using Shimano like we are here, then I'd recommend you have that upper jockey wheel perfectly
in line with the largest sprocket at the back. If you're using SRAM, it's good to actually just
put it a little bit beyond that largest sprocket. That enables you to have a dummy shift so when you
shift up past that biggest sprocket, it stops it just dropping it down a gear into your next
easiest gear. Don't go too far because you will defeat the purpose of the limit screw and then
you could end up throwing your chain off the cassette and into the spokes. Also, it can cause
your rear derailleur to catch on the spokes as well which is also bad and you don't want
that. Just be careful. We're now going to fit the chain. The procedure for doing this is slightly
different from if you're just doing a standard 2x groupset and that's because the derailleur
has different proportions. The technique to do it is to fit the chain around the largest sprocket
at the back and then also round the chainring, but we're not threading it through the derailleur.
The purpose of this is to get the correct chain length before we connect
both ends of the chain together. Now, with the chain threaded over the largest sprocket
at the back and round the chainring but not through the rear derailleur we want to then
look at where the chain meets and then add an additional four link pins along. If you see there,
the length of this chain here is correct. We've got where the chain meets and then we count one,
two, three, and then there's going to be a fourth because I'm going to connect it with a quick link.
When you come to connect the chain often find it easier if you actually put the rear derailleur
into the smallest sprocket as there's less chain tension and it's just easier to connect both ends.
Make sure you correctly thread it through your rear derailleur and it's not threaded through the
wrong way and is catching on the little linkage pin in the middle of the cage, I've seen people do
that. Also pay attention to the chain as well, as some chains are asymmetric, they have to be fitted
in a certain direction, such as the Shimano chain. Quick and easy way on a Shimano chain
to know if you've got it the right way around is the writing on the chain should be outward
on the drive side. I'm just going to use the quick link pliers to close the quick link as well.
Now we have the chain installed we want to make sure that the cable tension is correct,
and that the gears are properly indexed. To do this turn the crank ideally with the
bike in a stand like we have here and then shift through the gears. If when you shift
the chain rubs on the next sprocket. It's likely that the cable tension is too high and therefore
you'll need to loosen it slightly. If when you shift the chain doesn't move and usually just
starts to make a clicking sound but doesn't shift into the next sprocket your cable tension isn't
high enough and you will have to increase it. To increase it, simply turn the barrel adjuster
clockwise and tighten it slightly. To remove cable tension anticlockwise loosen it slightly.
Usually, this only takes a sort of quarter of a turn or half a turn at a time shouldn't need to
adjust it a great deal. [music]
Keep playing around with the cable tension until you get it just right and you find
that sweet spot, but a couple of troubleshooting things for you. If you find that no matter how
much you shift the rear derailleur doesn't move all the way up to the biggest cog on the
back and no matter how much you tighten the cable tension on the barrel adjuster it just won't go,
then the likelihood is that you just haven't pulled the cable through enough and you don't
have enough base-level tension in the cable. In which case undo the retaining bolt for the cable
and just make sure you've pulled it all the way through before re-tightening it. The other thing
is, that if when your gear change is a little bit sluggish from changing up or down from the
biggest cog at the back to the next biggest cog. Then what I'd suggest you do is actually just play
around with the B-limit screw and just nip it in a little bit tighter. If that's a little bit closer
bringing that jockey with a little bit closer to the cassette and that'll just make that gear shift
a little bit sharper. Once you've followed all those steps your gears should be working
properly on your One By Drive Train and all that remains to do, is to just check that the cable
is properly secured and tightened, trim it to length with a pair of cutters so that it's not
too long and then fit a ferrule on the end as well to protect it and stop it fraying.
I hope you found this video useful and if you have, please give it a thumbs up, help support
the channel. For more videos to do with Bike Maintenance and all things bike related tech,
make sure you subscribe to the GCN Tech Channel [00:14:16] [END OF AUDIO]