The 9point8™ Slack-R™ kit changes the head tube angle on bikes with IS headsets. (IS41 and IS42* upper bearing and IS52 lower bearing only.)

Have you found a Kit that fits your bike? There are convenient kits that group the parts you need HERE. But if you want to buy individual Slack-R parts, you are in the right place! You need three individual parts to adapt your bike (Upper Cup, Tensioner, and Lower Cup); use our KIT SELECTOR on the kit page to get the right combo.

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.

2. Confirm you have enough steer tube length to install a Slack-R If measurements A + B are greater than below 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.