9Point8 Slack-R Headset Review

What if you want a slacker head angle, but your bike won’t accept slackset-style headset cups? Enter the 9Point8 Slack-R!

• Brand: 9point8
• Product: Slack-R Headset
• Price: £119.99
• From: Shorelines Distribution
• Tested by: Chipps for 10 months

Not everyone is after a point and shoot, racy bike, right? The marketing blurb for my Yeti ARC hardtail reads something like “Far beyond a juiced up thorough-bred XC race bike, the ARC is built around a 130mm fork for a massively capable trail bike.”

“It’s your instant-feedback steed for any trail” – but what if I don’t really want instant feedback? It’s true that the Yeti ARC is a great trail bike, but after probably two years of ownership, I’d decided that it could probably do with chilling out a little. The Yeti, with recommended 130mm fork features with 67°/76° angles. Which is great for that instant-feedback feel of XC racing, or slinky, sinuous trails of the South Downs, but it can be a little much for loose, dry, rocky trails that I now find myself riding most of the time. It was a bike that I felt I needed to be fully-caffeinated in order to keep in line. At speed, it would still get knocked off line and any thoughts of ‘You could ride this and sell the full-susser’ went out the window. Indeed, my Singletrack World colleagues in the ‘rad’ office joked that the 2000s would like their geometry back…

I decided to get one of those slack-headset jobs, but reading the fine print on the Yeti FAQ, it seems that Yeti didn’t recommend it – and then from a practical point of view, the Yeti, like many bikes, features headset races moulded into the actual carbon of the head tube of the bike. Headset bearings simply drop in, so popping the headset out and pressing a new, slacker one, in was out of the question. It looked like I’d have to learn to love the twitchy beast.

Then, I discovered the Slack-R headset from Canadian company 9Point8 (makers of nice dropper posts too). The Slack-R is a three-piece replacement headset. The upper and lower parts feature the same chamfered edges as a cartridge headset bearing does, only instead of a bearing, it’s a machined sleeve that offers a new, slacker position for that bearing to sit – turning your integrated headset into a kind of external cup headset. The third part of the Slack-R is a sleeve that threads into both upper and lower new external cups and (using a special splined tool and socket set) pulls both headset parts tight together. You’ve essentially built a new head tube inside your existing one. It’s a complicated premise, but it’s simple enough once you see the parts, which themselves are neatly machined and smartly black anodised with 9Point8 graphics and notched so that you know how to orientate the two cups in your head tube.

There are a few requirements needed before you get ordering, though. You’ll need to measure your head tube and decide on one of (normally) two options for the new angle available. This will be affected by your head tube length: a shorter headtube has more potential for bigger angle adjustment. For my medium Yeti ARC, I had a choice between –1.4° and –1.7°. Benji would argue that everyone needs slacker and no one needs any half measures. Luckily, 9Point8 were nice enough to send me both kits to decide which I preferred.

Not every bike needs this level of intervention to get a slacker effective head angle, but 9Point8 lists compatible bikes that, among others, includes Cannondale, Norco, Marin, Orbea, GT, Revel, Scott and even some Specialized bikes. Basically, if your bike has ‘moulded-in’ headset bearing cups and you can’t press in a new cup, then this is probably what you need…

The other caveat with installation, is that you need around 20mm of ‘spare’ steerer tube. If you’ve already slammed the stem and scalped the steerer, you won’t get the Slack-R to work, as it’s effectively making your internal headset an external one. Luckily, I always chop my steerers conservatively in case I need to move the fork on to a different bike.

Installation

The kit comes as three boxes, containing the different upper and lower cups, along with the central sleeve (which uses a clever combo of regular and reverse thread to get the two halves to tighten together) as well as the sturdy splined installation tool.

What followed was then: remove fork, remove bearings (and around 20mm of stem spacers), clean everything up and get ready to install the two cups. 9Point8 recommends carbon paste to get the two cups to ‘bite’ and not rotate as you tighten. This is where you need a third hand or handy friend, as you need to place the upper cup in place – with its notch aligned with the centre line of the bike, and the lower cup along with the central sleeve. I added the recommended blue Loctite to the threads, to keep them from moving (more of that later) and then threaded the sleeve on a few threads to the lower cup before offering the lot to the upper cup and threading that on too. Then it got complicated, as you need to use the 9Point8 socket tool in the head tube to tighten the two cups together. While doing this, you need to make sure that neither cup twists (its slot from the centreline of the bike) or you’ll end up with a slack headset on the wonk. As the tool is only an interference fit on the central sleeve (and it needs a 19mm socket and an extension bar, so it’s constantly falling off the tool) I kept dropping the socket while trying to keep the two cups from moving while I tightened.

After a lot of fishing around on the floor for the tool again, I got it all installed in about half an hour and was ready to reinstall and ride! The old cartridge headset bearings drop straight in and the fork and stem bolt on as normal, only with a few spacers fewer.

First and second impressions

Using my not very accurate method of angle measuring using my phone, my head tube angle had changed from a ‘before’ of 67° to an ‘after’ of around 65°, which was good enough for me. The front axle was now around 10mm further away from the bars, due to its new ‘external’ headset, which helps with that new angle measurement. Meanwhile, the handlebar position hadn’t changed due to the addition of the top cup, but the removal of 15mm of spacers.

On the trail, the feeling wasn’t dramatic, but it was noticeable. After a single on-trail tighten of the headset bearings, I got on to riding all my favourite spots. The bike felt calmer and more composed on the front end and I noticed the babyhead rocks of my regular descents had way more effect on my rear wheel now, rather than the whole bike bouncing around.

After a week or so, I felt I needed to tighten the headset again, but when I did, I felt some binding when rotating the bars. This turned out to be due to the lower cup having rotated around 30° in place. I’d obviously not tightened it properly, so I went back to the workshop, re-Loctited the threads and re-carbon greased the cups. Most importantly, I paid particular attention to tightening the cups correctly and making sure there was no creep while cranking the three parts together. There’s no real way of manually stabilising the cups (like with a spanner, pin-spanner or whatever – it’s just hands and carbon grease), so you need to make sure they’re in line, and stay there, while you tighten the central sleeve. After my first re-do, the headset hasn’t budged at all. I’d still suggest throwing the splined tool in your bike bag if you’re off racing or travelling, as no other tool from a regular bike shop can replace it if you need to tighten things up, mid-holiday…

I initially installed the –1.4° kit, but later on went back in put the –1.7° kit in. To be honest, the 0.3° change between those two was hard to notice, compared to the noticeable calming that the –1.4° kit had from stock. I suggest to be like Benji and just go full-on first time.

Niggles

There have been a few issues. Mostly when I went to swap over between the two angled sets, I discovered that I’d completely overdone it on the Loctite and only one cup budged from the centre sleeve. In the end, I had to drill a hole in the central sleeve to put a screwdriver through, so I could brace it and use the tool on the other part. Lesson learned.
One other reported issue is of a slight creaking in use. I hadn’t noticed this initially, but watching GoPro footage confirmed that there was a creak on bigger hits. Opening up the system, you see how the carbon grease dries out over time, leaving just a dry white paste. I’m about to lightly grease things all over as well and see if that cures things.

And, to aid installation, it would be great to have a way of stopping the cups from spinning as you tighten the central section with the tool. Spanner flats might be a little too old school, but a pair of pin spanner holes might be a subtle addition. And if 9Point8 can find a way to re-engineer the tool socket to accept a more commonplace workshop tool, that would save a lot of travel worry for riders.

Conclusion

Needless to say, installing this 9Point8 Slack-R headset kit will usually void your frame warranty. I waited a year and decided I’d take the chance anyway and I’m delighted with the performance. I’m certainly not a ‘slack-sled’ disciple, given that I’m not a rad downhiller and way more of a trail rider, but I’ve been really impressed with how this kit has made my bike less nervous and my descending more confident. And on climbs, I can still get round those tricky switchbacks on the climbs… In terms of value, it’s a really nicely machined bit of kit and the instructions and advice on the website on what fits which bike is invaluable. It’s not cheap, but it’s made my bike more enjoyable to ride, more confidence-inspiring and shelved any ‘Ooh, should I swap the frame for something radder’ thoughts. And from that point of view, it’s a bargain. Way cheaper than shopping for a new frame.

Review Info

Brand:	9Point8
Product:	Slack-R Headset
From:	Shorelines Distribution
Price:	£119.99
Tested:	by Chipps for 10 months

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