9point8 Announces the Slack-R Headset Angle Adapter

Jul 23, 2020 at 6:42
by 9point8  
Slack-R Press Release Media


PRESS RELEASE: 9point8

We are pleased to announce our Slack-R, the only headset angle adapter for bicycle frames using the IS Standard. Utilizing our patent-pending modular system, customers can change their head tube angle (HTA) to slacken or steepen their geometry.

Slack-R Press Release Media

The Slack-R kit is installed in the Head Tube of an IS frame, and re-uses the IS bearings.

Slack-R Press Release Media

9point8 Slack-R Press Release Media

The available delta in Head tube angle is 1.2deg to 1.8deg, dependant on the specific geometry of the bike. How does this work?

CASE STUDY: Santa Cruz 2016-2019 Tallboy 3, size Large

9point8 Slack-R Media Release
9point8 Slack-R Media Release

Figure 1: Santa Cruz Tallboy 3 Slack-R Transformation

Using the 2016-2019 Santa Cruz Tallboy 3 in size Large as an example. This is a great candidate for a Slack-R – it uses an IS headset and despite the 68° head tube angle we see a lot of riders wanting to make it slacker, similar to the 2016-2019 Tallboy! Two Slack-R kits are available for the Tallboy 3 (100mm head tube length), the “Bravo” kit 1.4-degree head tube angle delta and the “Echo” kit 1.8-degree head tube angle delta. The delta indicates the change in angle of the steer tube in your frame, but because of the combined effect of the increase in stack height from the bearing cups and the lowering of the front end due to the slacker head tube able, this doesn’t tell you exactly what the end result is. Using the Bravo kit the resulting geometry on the Tallboy is shown in Figure 1: Santa Cruz Tallboy 3 Slack-R Transformation. Despite only a 1.4° delta, the overall change is actually 1.7°! Generally speaking, we expect a slightly slacker head tube angle than the listed delta. Remember, changing the head tube angle and adding cups to your headset will make other changes to your geometry:

• Small change in bottom bracket height
• Slight increase in stack
• Slight decrease in reach
• Noticeable increase in wheelbase


Slack-R Press Release Media
Slack-R Press Release Media
Slack-R Press Release Media

The Slack-R is available now at 9point8.ca or through your local bike shop. MSRP $99USD

Author Info:
9point8 avatar

Member since Apr 29, 2015
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113 Comments
  • 56 1
 That's pretty awesome.... Hell, they should even make ZERO degree sets, just so carbon bikes with poor tolerances can have their headsets seat properly.
  • 4 0
 Exactly - some IS headtubes in very expensive bikes have tolerances absolutely miles out.
  • 21 6
 After binge watching Hambini videos recently, I can attest to this LOL.
  • 7 3
 @Ryan2949: Agree. Hambini has spoiled for us a lot of things in cyclyng industry
  • 1 0
 @justanotherusername: just more examples of the quality carbon manufacturing in the bike industry...
  • 2 10
flag Super7 (Jul 23, 2020 at 22:34) (Below Threshold)
 Nice idea. Let's hope it's more reliable than their dropper posts.
  • 9 3
 HELLO HAMBINI FANS!
  • 3 1
 Not just headsets. I spent 2 hours yesterday using a contraption of straps and clamps to get my shock in to a canyon spectral without cross threading the bolt... Absolute joke of a bike that thing...
  • 31 0
 Does this make my 2019 XC bike a 2021 Down Country bike?
  • 21 0
 Put this to Grim Donut!
  • 1 0
 Yes.
  • 16 1
 I love the Works Components -2° angle headset I installed on my Chromag, but this screw-together design looks really promising and DIY friendly for home mechanics. It's great to see more products like this on the market for adjusting your existing bike to work for you, as opposed to buying a new frame.
  • 5 2
 It’s a great solution for the IS headtube option, not something I think is required for standard push fit headsets though, lots of extra complication for no real gain.

Super good job for those with IS frames though, so pretty much every specialized and Santa Cruz.
  • 2 0
 I have 2 sets of -2 degrees, and another 2 on my friends' bikes - awesome stuff rocking hard after several years of abuse. Highly recommend.
  • 1 0
 @bnegative: works stuff is good, but they didn’t crack the IS thing like these guys did - I asked them a year or so back and they said it was a non starter for them basically.
  • 1 3
 Hey, I just put a Works Components-1 and I love what it did to the bike but it is the creakiest headset ever. It sounds like my headset is making popcorn whenever I ride it. Is yours super creaky also? It's been on for 2 days and was professionally installed.
  • 1 0
 @Canieto1: I have only ever had one works headset and no noise what so ever - most people buy them over a cane creek for this reason.

Sounds like the install isn’t right or something - you email them?
  • 1 0
 @Canieto1: sure its not your CSU?
  • 1 0
 @Canieto1: bring it back to the shop. They installed it, they should help you out. If they don't there not any good
  • 1 0
 @Weedling: I'm not sure, but I'll ask about that. Thanks.
  • 1 0
 @justanotherusername: Thanks for the feedback. I'm bringing it back today to have them unf*ck it.
  • 1 0
 @Canieto1: mine has been perfect since day one, no noise at all and no settling in or loosening.

Did your order the headset, or did the shop? The reason I ask is because the Works Components headsets need to be matched to the length of your headtube. If the shop installed the wrong one, it would definitely be creaky and not tighten up correctly...
  • 1 0
 @pnwpedal: I ordered the headset but with the guidance of the shop and I I quadruple measured everything to make sure I had the head tube right. Mine was right over the borderline on two sizes. I wouldn't put it past me to do it wrong though. That's good info I may just have to order another set
  • 2 1
 @Canieto1: Ill ask again - did you email Works for advice before asking the internet?

This kind of thing gets up my chuff, why essentially bad mouth a product / brand before even finding out what the issue is?
  • 1 0
 @pnwpedal: doubt that’s true btw, I asked works if I could swap my headset over to a new frame with a longer (+15mm or so) headtube and they said it would be no problem, I would just get a smaller angle change.

Creaking / popping sounds like something’s not installed right or a bad part / bearing, not a headset fractions of a mm out.
  • 1 0
 @justanotherusername: oh sorry no it just started last night I figured with the weekend and all I would do it on Monday
  • 1 0
 @justanotherusername: oh I just saw your second part of that. Yeah I get your point I should have just private messaged him cuz I really don't want to give the company a bad name if it's my fault which it may very May well be. The purpose of my post was more just to ask if that guy was having problems with his cuz I didn't know if it was characteristic of the product or not. To everyone listening to me talk about Works components: we haven't ruled out user error yet here in my case. But this is also the third thing in a row that this well-known shop in my neck of the woods has screwed something up so I think it might be that too. I will not name that shop. And before you ask, I keep going into that shop because they have the lowest wait times right now.
  • 1 0
 @Weedling: the shop said they're going to look at that also but it wasn't like that before.
  • 1 3
 @Canieto1: I’m not sure a product with the characteristic of creaking would be very popular, surely?

So you are happy to publicly bad mouth the component manufacturer but not the shop that may be the cause of the issue? (For what it’s worth, I don’t think you should have mentioned it at all publicly until you worked out what’s up)

I wonder how many product ‘issues’ are people installing them wrong or just plain not asking for support from the supplier before announcing the issue online....
  • 1 2
 @Canieto1: oh and for the third time, have you actually contacted works yet?
  • 1 0
 @justanotherusername: that's why I didn't name the shop. I was trying to learn from what you told me. If I had had you solid advice prior to mentioning the headset mnfr, I would have never mentionred it in the first place. I've searched quite a bit i seem to be the only one having this problem. Regarding your first comment about " I'm not sure a product with a characteristic of being creaky would be very popular" Cane Creek still sells theirs, as you mentioned.
  • 1 1
 @Canieto1: you got me there about the cane creek, I’ll give you that one, maybe not so silly a question after all ;-)

Five works an email anyway, between you, then and the shop I’m sure it will get sorted out, it’s a only headset, not a particle accelerator after all.....
  • 1 0
 @justanotherusername: I already answered that one time ago. Look up and you can find it
  • 1 1
 @justanotherusername: the cups and angles absolutely need to be matched to a specific headtube length. The Works Components style is pressed together with a specific alignment, with no rotational adjustment like the gimbal system in a Cane Creak that aligns the top and bottom bearings.
  • 1 1
 @pnwpedal: Would you like me to quote he actual reply by the actual manufacturer of the actual part (I’m sure I have the email somewhere) or would you prefer to just make it up based on your own understanding?

It’s fractions of a mm and degree we are talking - do you think most frames are even made to that kind of tolerance?
  • 1 1
 @justanotherusername: I don't doubt that you had a conversation about that, but that doesn't make what I said any less true. Proper alignment of press-fit bearings is crucial. Anyone who knows anything about machine design will agree with me.
  • 1 0
 @pnwpedal: me thinks you are confusing high rpm precision machinery to a low rpm, low tolerance, angular contact bearing (very specific to a headset) with chamfered seat and contact points. You also directly contradict actual manufacturer advice but no matter, you are right ‘on the internet’ ..... or something....
  • 1 0
 @justanotherusername: okay, I'll be wrong here. Doesn't matter to me. If your headset works in the different size frame then that's awesome.
  • 1 0
 @justanotherusername: UPDATE. on my evening ride my headset completely stopped creaking. That must be bedding in?
  • 8 0
 Bravo! Finally some true innovation in backwards compatibility. Well done, 9Point8 crew! : )
  • 5 0
 I had a works component installed on one of my previous bikes. The issue is that lengthening the front end without doing anything to the rear seems to take the weight off of the front, which makes itself present even on DH runs. I found that you need to compensate with a 20mm longer stem.
  • 2 2
 @phops You could also decrease your sag in the back, run your fork/fr tire softer,remove a stem spacer. Would be easier and free.
  • 2 0
 @foggnm: Sag would not do anything for wheelbase, running a softer fork/tire has other negative effects, and stem spacer doesn't make the bike feel good when out of seat cause you just get leaned over further with handlebars under you rather than infront of you
  • 1 0
 A longer stem as well as a reduced offset fork help bring the wheel back.
  • 1 0
 @pipomax: But by adding the slack-r and reducing offset, you're increasing your trail measurement twice. It might make it harder to steer. I'm wondering if it might be better to us an increased offset fork on any bike that uses the slack-R to so that your trail measurement doesn't change too much...
  • 7 0
 Guessing you can also use it on a Trek to ditch the awful 'Knock Block' and give the fork crown the clearance... ??
  • 5 0
 I bet this makes some fans of knockoff chinese carbon frames very very happy Smile
  • 1 0
 Indeed!
  • 2 0
 So a quick note for people who want to buy these: Take your headset apart and measure your head tube before ordering!

You'll want to make sure that the smallest ID in your IS41 upper bearing cup is > 34.5mm and that the smallest ID of your IS52 lower bearing cup is > 44.5mm. This is needed in order to clear the barrel of both slack-r bearing cups. Additionally, make note that this is intended for IS41 upper headsets, not IS42. The taper is the same angle for both, so you might get lucky if you have an IS42 upper bearing cup, but when in doubt, take some measurements and pictures and email 9point8 before buying. They're cool people and they're very responsive to emails. They've been very helpful to me as I've discovered that their product unfortunately does not fit my frame. +1 for them as a company though.
  • 2 0
 Noooooo, that is just silly (sarcasm).
Just take sandpaper to your carbon frame and make it look better than factory....
www.youtube.com/watch?v=PRYIzYa7mxg
  • 2 0
 I had the chance to install one of these on a Carbon Chameleon lately. There were a few gotchas (had to modify the frame a bit), but I'm really pleased with the outcome. Bravo 9point8 for figuring out a solution nobody else could figure out.
  • 2 1
 The supplied drawing is very useful for illustrating how the bike’s geometry will be altered.
But dunno if I’d want my bike’s wheelbase increased, is already longish.
And I’ll admit I have no idea what an IS headset is.
Internal S——-
Integrated S——-
Industrial Strength
International Standard
  • 7 0
 www.parktool.com/blog/repair-help/standardized-headset-identification-system
  • 5 0
 Now you can turn the SB115 into a proper bike Smile
  • 4 0
 I've been machining my own, I'm glad a professional company is doing it. It's an utter ball ache to do.
  • 1 0
 Well, has someone mounted the 9point8 Slack-r headsets on their top fuel? I would be interested in trying it to get more launch on my fork !! Do you know how it would affect the seat tube?
sorry for my english, i use google translator
  • 4 0
 Now just need an IS reach adjust headset . . .
  • 2 0
 Like GG has?
  • 1 0
 @laksboy: Tell me more . . .
  • 1 0
 @noplacelikeloam: I think he is mistaken, they have their own custom fit headset specific to their frames but not a IS standard headset.
  • 1 0
 @justanotherusername: Yeah just checked it out. Too bad.
  • 1 0
 @laksboy: aluminum frames, nit the carbon frames.

I’m waiting hit GG to made an angleset for the Revved frames
  • 4 0
 Looks like I found the next piece to my Stumpjumper puzzle....
  • 1 0
 Exactly!
  • 2 0
 Emailed 9point8 to check compatibility with my '16 stumpy and it doesn't seem like it will fit Frown
Here's their response:
"You will want to confirm with Specialized or a Specialized dealership on what headset standard is being used. Specialized I believe uses IS42 Upper Headsets. Slack-R is only compatible with IS41 Upper Headsets."
  • 1 0
 @wood80:

did you ever find out if one of these would work on a stumpy?
  • 1 0
 @Spidersanta: it wouldn't work on stumpy Frown I used offset-bushing instead (from 67HA to 66.5HA)
  • 1 0
 @wood80: hopefully they offer bearing cup sizes soon.
  • 2 0
 really hated it when santa started to switch to is headset from formerly perfectly zs headsets...why???
  • 2 0
 It allows for much larger tolerances when making those $3000 frames - I mean every cent counts.... ;-)

An IS headtube is a drop in bearing, no interference fit tolerance needed.
  • 3 1
 Why wouldn't you just add that height to your fork and get the benefits of extra suspension as well
  • 1 1
 Because that will raise your bracket height and make the bike less stable.
  • 3 4
 @0li4k adding a cm to your headset cup will raise your bb the same and not give you the benefit of extra suspension. I worked for these guys they don't think before they produce product. The guy who designed it and who's bike is shown in the image thinks bb heights are too low already
  • 1 0
 Umm, no. Adding a cm to your headset cup will raise your bottom bracket around 1/3 of that or 3mm.
  • 2 1
 @rete: adding a cm to your fork travel (by swapping to a longer air spring not changing the chassis to a burlier fork which will also have a longer axle to crown) will raise the bb is exactly the same as adding a cm tall cup under the head tube except the all important fact that the longer air spring also gives you more travel
  • 3 0
 @myotherrideisyourmom: yeah, no. Basic geometry says it's not so. If the BB was right under the head tube then yes, but it's around 2/3 of the way toward the back of the bike, which doesn't move. Place a broom flat on the ground and lift the one end 10cm. Then measure how high the middle is off the ground (it will be 5) and 1/3 from the end still on the ground (3.33 off the ground). Same thing here.

You can see from the diagram above that the BB raises 2mm despite the 10mm fork extension - in this case because the wheelbase extension also somewhat drops the whole bike when you rake out the fork angle.
  • 2 0
 @rete: adding a cm under the headset cup is exactly the same as as adding a cm to fork travel. I would rather take the extra travel. I don't know why you cannot understand that
  • 1 0
 @myotherrideisyourmom: of course it's the same, I don't dispute that. But lengthening your fork 10mm does not raise your BB by the same 10mm (your statement). The rear doesn't raise 10mm as well, it stays the same. BB lift is around a third of the front wheel lift, and if the fork rake is extended as well as in this case, 2mm BB lift for the 10mm fork lift, and 1.8 degree slacker.
  • 1 5
flag myotherrideisyourmom (Aug 8, 2020 at 4:25) (Below Threshold)
 @rete: at no point did is say it raises the bb 10 mm quit putting words in my mouth this conversation is over
  • 4 0
 @myotherrideisyourmom: your first post "adding a cm to your headset cup will raise your bb the same" literally is the first thing you said
  • 1 4
 @lognar: I was replying to an earlier comments about someone saying adding the cm to the fork raise bb more my phone would not let me reply directly I guess I forget to at the person. Pinkbike comments just like this product bring no benefit to society
  • 2 0
 almost 2 degrees is huge!
  • 3 8
flag Pichy (Jul 23, 2020 at 10:50) (Below Threshold)
 The only problem I see is the seat tube angle would also be slacker needing to move the seat forward. That and the reduced reach could make you feel cramped when pedalling.
  • 11 1
 @Pichy: your not making a longer ATC, your just changing the headtube angle. if anything the slacker HT angle would drop the front end (very very very slightly) which would then steepen your seat tube angle. The reduced reach is also minimal because its only affecting the exposed length of steerer tube. you only loose 6mm for 2 degrees!!! thats nothing.

The way your thinking is if we were to overfork the bike. but its not the case here.
  • 1 0
 Superstar Slackerizer headset changes the HTA by 2deg too.
  • 2 0
 @vinay: it isn’t an IS headset though, same as the Works Comp ones.

This is the first and I think only IS option - it’s the whole reason they have made it screw together.
  • 1 6
flag blazersdad89 (Jul 23, 2020 at 11:22) (Below Threshold)
 @BoneDog: With the lower bearing being moved outside the frame, this will affect the seattube angle quite a bit. Reach and stack may not be changed too much but it's likely that any change made to the headtube angle will be the same for the seattube angle.
  • 9 0
 @ihatton929: not at all - the external lower cup will just counter the lowering effect of lengthening wheelbase - I imagine the change to STA will be fractions of a degree.
  • 4 0
 @justanotherusername: You are correct, the gain in stack from the external cup is generally offset by the lowering effect that goes along with the HTA change. You can see in the diagram, there's very small change in BB height, and therefore STA as well.
  • 2 0
 @jduffett: Exactly. For example I installed a -1.5 works components angle set on my Hard tail. Since the original headset was already external, the works part only increased ATC by a couple of mm. The net affect actually felt like a slightly longer reach (and slightly steeper seat angle) due to lowering the front end. I had already purchased a 5mm longer stem to compensate, and never needed it.
  • 1 0
 @justanotherusername: Ah, I now understand IS headsets are integrated headsets where the head tube serves as headset cups. I wasn't aware these still existed as I recall people used to bitch about them so I kind of thought they must have gone extinct by now. We already have press fit bottom brackets now after all so the comment section will continue to be inspired. Either way, internal headsets are clearly still here now and indeed for those who like to tinker, it is nice that 9point8 went all out to create such a complex product.
  • 1 0
 Make one for a straight steerer tube so that I can revive my old hardtail frame, please.
  • 4 0
 Works Components do one for straight steerers. Press fit only, no IS.
  • 2 0
 You can use a 1,5" to 1-1/8" reducer crown race to make your straight steerer tube fit any tapered frame. If I'm not mistaken Works Components, among others probably, makes those.
  • 1 0
 @Velocipedestrian @Oli4k
Thank you guys! Works makes 1 degree angle set (but not 1.5). Also, I found a pink bike member machines a custom 1.5 degree angle set for 1 1/8 straight steerer. www.pinkbike.com/buysell/2185738
  • 1 0
 How much longer steer tube does one need for this?? My WORKS used up all extra length.
  • 1 0
 20mm
  • 1 0
 Can people actually feel one degree of HTA difference? Love to see a test where riders have to guess which is which.
  • 1 0
 I had a bike with a 2* adjustable head angle (2006 Commencal Mini-DH). When I switched it to steep mode, I expected the difference to be subtle, but found it very obvious. I only rode like that once before putting it back in slack mode for good. It's not hard for me to imagine half that difference still being tangible.
  • 1 0
 @AndrewHornor: I turned my Norco range VLT which comes standard as 27.5 into a mullet Bike by putting a 29 inch front wheel and Fork on it and the one degree increase in slackness(63.5 to 62.5) made the bike handle
noticeably worse but it was still fun. I got a Works components 1 degree angle set to bring it back to 63.5 and it handles noticeably better. Creaks like a MF'r now tho. I'm working on that...
  • 1 0
 @Canieto1: I'm surprised those changes only added up to 1*.
  • 1 0
 @AndrewHornor: It came with a 180 27.5 fork and I switched to a 160 29 fork. With the original 27.5 x 2.5 inch rear tire the head tube angle got down to 62 even. So I switched to a 27.5 x 2.8 eddy current in the rear which is slightly taller and that got me back 62.5 and that's when I decided to go with the angle set also to get me back to the factory 63.5. I really should have just gotten the sight VLT 29 but it wasn't out when I got the range and I wanted to try a 27.5 bike but I it turns out I just like having a 29 up front. The whole thing's been kind of a shitshow and expensive shitshow. It turns out I don't know more than somebody with an engineering degree in 20 years of bike design experience LOL. I have vowed to never again mess with geometry. I still love the bike and the end result tho.
  • 1 0
 @Canieto1: no kidding you really got into it. Good that it ended up working out for you!

I'm running a 27.5 bike with 26+ tires and a 26er fork, so it's a little low and steep. For the most part I like how it rides but I pedal strike a lot, so eventually I plan to switch the fork and front wheel to 27.5 which will make it very slightly slacker than stock... hopefully all for the better and not an experience like yours lol!
  • 1 0
 This is awesome. Great job 9.8!!
  • 1 0
 I wonder if this will fit on my 2014 Specialized Enduro?
  • 1 0
 It is probably ok, however in case you doit you need new frame
  • 1 0
 Just need this available in the UK now!
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