Kit | HT Length | Upper Cup | Min L | Max L | Lower Cup | Min L | Max L | Tensioner | L | |
---|---|---|---|---|---|---|---|---|---|---|
Alpha | 90-98 | 0000-1343 | 22 | 26 | 0000-1349 | 25 | 29 | 0000-1345 | 43 | |
Bravo | 100-108 | 0000-1343 | 22 | 26 | 0000-1349 | 25 | 29 | 0000-1346 | 53 | |
Charlie | 110-118 | 0000-1343 | 22 | 26 | 0000-1349 | 25 | 29 | 0000-1347 | 63 | |
Delta | 120-128 | 0000-1343 | 22 | 26 | 0000-1349 | 25 | 29 | 0000-1348 | 73 | |
Echo | 97-105 | 0000-1343 | 22 | 26 | 0000-1350 | 32 | 36 | 0000-1345 | 43 | |
Foxtrot | 107-115 | 0000-1343 | 22 | 26 | 0000-1350 | 32 | 36 | 0000-1346 | 53 | |
Golf | 117-125 | 0000-1343 | 22 | 26 | 0000-1350 | 32 | 36 | 0000-1347 | 63 | |
Hotel | 127-135 | 0000-1343 | 22 | 26 | 0000-1350 | 32 | 36 | 0000-1348 | 73 | |
India | 110-118 | 0000-1344 | 42 | 46 | 0000-1349 | 25 | 29 | 0000-1345 | 43 | |
Juliet | 120-128 | 0000-1344 | 42 | 46 | 0000-1349 | 25 | 29 | 0000-1346 | 53 | |
Kilo | 130-138 | 0000-1344 | 42 | 46 | 0000-1349 | 25 | 29 | 0000-1347 | 63 | |
Lima | 140-148 | 0000-1344 | 42 | 46 | 0000-1349 | 25 | 29 | 0000-1348 | 73 | |
Mike | 117-125 | 0000-1344 | 42 | 46 | 0000-1350 | 32 | 36 | 0000-1345 | 43 | |
November | 127-135 | 0000-1344 | 42 | 46 | 0000-1350 | 32 | 36 | 0000-1346 | 53 | |
Oscar | 137-145 | 0000-1344 | 42 | 46 | 0000-1350 | 32 | 36 | 0000-1347 | 63 | |
Papa | 147-155 | 0000-1344 | 42 | 46 | 0000-1350 | 32 | 36 | 0000-1348 | 73 |

















The 9point8™ Slack-R™ kit changes the head tube angle on bikes with IS headsets. (IS41/28.6 upper bearing and IS52/40 lower bearing only.)
Confirm the three checks below and complete the drop down menus to see what Slack-R kits are available for you.
1. Confirm your headset is the IS Standard. If you are not sure,read this article on Headset Identification by the experts at Park Tools.
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2. Confirm you have enough steer tube length to install a Slack-R If measurements A + B are greater than 20mm there is enough steer tube to install a Slack-R ![]() |
3. Measure or look-up your bike's head tube length (HTL). Bicycle manufacturers often list your bike's HTL in geometry charts on their websites. You can also measure this yourself as shown below.
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What does installing a Slack-R do to your bikes geometry?
Click HERE to take a deeper look.
Want more customization? Add additional parts to your Slack-R Kit to fine tune your HTA and test the extremes. Individual parts located here.
Does your bike have a Trek Knock Block headset? The Stop Chip must be removed from all Trek Knock Block headsets before installing a Slack-R. Read more here.
Slack-R Kits
- Product Code: Slack-R
- Availability: In Stock
USD$99.00