Hey everyone, here's a scenario for you:
you still love that bike but you would really want to try a slacker head angle on that same bike.
I mean 70 degrees head angle in 2022 is not exactly confidence inspiring.
Luckily my fellow Canadians at 9point8 came up with the Slack-R, the Slack-R kits allowing us to change that,
Let's check it out!
While pretty much everything you need to know about Slack-R is well explained on the 9.8 website
there's still a couple of gotchas, the installation that I want to cover in this video so let's get to it.
And this TREK, the previous generation Top fuel frame,
has an integrated headset just like many other modern mountain bikes today
and that doesn't give you a lot of options.
But that is exactly what Slack-R is meant to do, address the needs of bikes with IS bearings.
But one thing that I have to bring up before we even get into this
is a compatibility concern that is clearly mentioned in their troubleshooting.
And what I'm talking about is 20 mm of steerer available here at the headset.
This bike was set up for racing with the stem slanted all the way down to the headset
so we only have about 5 mm of steerer available.
So unfortunately this TREK Top Fuel with this FOX 32 with a really short steerer cannot take the Slack-R the way it is.
My yeti SB100 though has 2 x 10 mm spacers under the stem so in this case I could install the Slack-R kit no problem.
And I call this a slacker kit because slacker it's a modular assembly
consisting of the upper cup, the what's called the tensioner, or the middle section and then the bottom cup.
And if you are asking yourself the question how do I know which pieces to choose, don't worry about that!
The first thing that you have to do after making sure you have enough steer is to measure your headset length.
Then go to the 9point8 website to the Slack-R kits page and plug that information here on this drop down menu.
If I choose a 100 mm what you're going to see is the two kits available for your bike:
a 1.4 degree kit and a 1.7 degree kit.
In our case we have a 90 mm head tube so the only option available is this Alpha kit
that provides us with 1.5 degree.
And you can use that to make your headset slacker or steeper depending on your application.
Once you select that
you're going to be taken to this page where you can clearly specify whether you have a Specialized frame or not.
in this case it's a Trek
and the last thing to choose here is whether you have an IS41 or IS42 headset.
IS41 or IS42 refers to this internal dimension of your IS frame prep
you can see you have a 45 degree angle here that your bearing is gonna sit on
and you have an internal dimension that I'm going to mention later on as well.
But if we just measure this frame, this is going to be 41mm and a tiny bit.
That is also the external dimension of this top headset bearing so this is an IS41 frame.
And you have a separate setting for Specialized bikes because they don't follow the same headset standards.
Also Specialized bikes will require 24 mm of available steer so keep that in mind even a longer steer than all the other bikes.
In our case 20 mm, IS41, let's install it!
And the details of that are right here at the bottom of the ordering page
where you're gonna see the installation instructions
we've already completed this step number 1 that is asking you to remove the fork.
Parts and tools needed for the install:
in this Alpha kit you're gonna have three pieces like I mentioned,
the specifics of them are here mentioned in the back.
And that includes this proprietary tool that's included in the same box with the tensioner
and then you're gonna need Loctite blue,
you're going to need - this is carbon paste whether you install this kit on an aluminum frame or carbon frame this is still recommended.
You're going to reuse the existing headset, you might need a little bit of tape and a marker
and finally you're going to need a torque wrench
with an extension and a 19 mm or 3/4 inch socket that would fit this proprietary tool from 9.8.
The design of this is pretty slick and interesting: what you're doing you are recreating a head tube inside of your head tube.
The three pieces are threaded together, the bottom thread is lefty tighty, so left hand
the top thread is righty tighty, and you're building this up inside your frame.
If you look here at the top and bottom cups, you're gonna see how now
they are offset versus the position where the bearings were before.
And that's how you're getting that steerer a bit slacker, assuming that's what you want to accomplish.
Obviously you're going to apply Loctite here on the threads of the two pieces
and carbon paste where the upper cup and the lower cup are going to touch the frame.
And I'm talking about this 45 degree area here or surface where the angleset touches the frame.
And once installed, we're going to reach from the bottom
and we're going to tighten - this is the final tightening of the headset inside of your frame
9.8 recommends 30 Nm as the perfect torque that's not gonna damage your frame.
Both the upper cup and the lower cup have this line here that has to be aligned with the center of your frame.
That way you have these new exterior cups properly aligned so they can provide you the new head tube angle.
Next step is to clean your frame very well with isopropyl alcohol.
Make sure that you can fit the three pieces through your headset.
There will be situations on certain frames where this inside or internal dimension of your is prep is too small.
And that is because the IS headset standard introduced by Cane Creek by the way
doesn't really mention the minimum opening here of your frame, it only specifies the maximum.
So if your cups don't fit into the frame you're going to have to take some sandpaper and just make this hole a bit larger
but in case you have to open this bearing seat a couple of millimeters,
9.8 recommends using a 1 inch diameter drum sanding bit and a hand drill.
That's not going to affect the integrity of the frame as the bearings only rest here on that portion
the 45 degree angle that you see here on the sides.
Also some frames might have the cable routing as a tube-in-tube starting right here at the front of the frame
and that could interfere with the use of the Slack-R obviously in this case for this TREK that's not an issue.
If you have a newer TREK with a Knock-Block the Slack-R is going to allow you to use a regular stem
as you don't install that Knock-Block anymore.
Also, because of the extra height of the bottom cup,
your fork is most probably going to clear the frame but you have to check for that.
I use that masking tape and the Sharpie to mark here the middle of the frame,
you're going to have to do this at the top and at the bottom of the frame.
Apply a bit of carbon paste here on that 45 degree angle area,
remember you're gonna do this for both top and bottom cups.
Apply the same paste right here where the upper and the lower cup is going to touch the frame.
And after applying some Loctite blue on the upper cup and the tensioner...
and I'm going to freeze right here to say don't use that much Loctite this is way too much!
Only cover a couple of threads or even better use anti-seize if you just want to test it out on your bike.
You're going to connect the tensioner first to the bottom cup.
Next you're going to insert the top cup, grab that socket extension with the 9.8 proprietary tool,
reach out from the bottom of the frame
and you're going to start to tighten this together by hand.
But don't go more than a couple of turns because you're going to look for that center mark
and I have it nicely lined up here at the top,
and while holding on that top cup so it doesn't move, you're going to line up the bottom cup again with the center of the frame.
So now you're gonna have to hold on to the upper and the lower cup and continue to tighten them together all the way to snug.
Then grab your torque wrench and tighten the whole assembly to 30 Nm like I mentioned.
And this is a complete installation of the Slack-R kit!
And we now have a frame that is 1.5 degrees slacker has a slightly higher stack height
and you're gonna have a slightly higher bottom bracket as well, but think about 1 millimeter or 2
not the whole height of the bottom cup.
And the only thing to be done is to clean these new cups, grease them and reinstall your fork,
and I bet that you can't wait to give this a try.
Now the Slack-R is 100 bucks, it does transform your bike I would say enough to make a difference
1.5 degrees slacker hend angle is going to help you on the downhills, it might affect your climbing as well
but I would say don't give up too easily and if you started down this path of modifying your bike
don't be afraid to move your saddle up and down change the stem length whatever else might be to readjust to the new geometry.
And if you stuck with me for this long, check in the description of the video for a 10% discount on Slack-R, thank you 9point8!
Remember not to put a lot of Loctite on the threads of the Slack-R if you ever want to take it down,
let me know if you have any questions,
don't forget to like subscribe and comment
and until next time hope to see you folks on the trails.
Cheers guys, cheers!