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 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.

What does installing a Slack-R do to your bikes geometry?

Click HERE to take a deeper look.

CompatibilityThe Slack-R is compatible ONLY with bikes using the IS41/28.6 upper headset bearing.  Some frame specs are listed as IS 1 1/8" 1 1/2" but this is NOT enough information to determine compatibility, since IS 1 1/8"  1 1/2" covers bikes with an IS41 and bikes with an IS42 upper bearing.  IS42 upper bearings have an outside diameter of 41.8mm and ARE NOT COMPATIBLE with Slack-R.  Only bikes with an IS41 upper bearing, which has an outside diameter measurement of 41mm are compatible.  For example most Specialized mountain bikes use an IS42 upper bearing and are NOT compatible.  Sorry Stumpy owners...  Contact [email protected] if you are unsure.

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.