How to Replace a Pre-Curved Arc Stay in Your Ultralight Pack
By Zpacks | Level Up Your Next Adventure | Published: 2026-10-16
Category: How-to Guides
Learn how to swap the pre-curved vertical stay in Zpacks Arc-series packs, including checking and replacing the stay holster inserts that protect the frame pockets.
Quick answer
To replace a pre-curved arc stay, slide the old stay out of the top and bottom webbing pockets, check the stay holster inserts for wear, then slide the new pre-curved stay into the holsters and confirm it seats fully. Replace the holster inserts if they are worn or damaged. This process fits Zpacks Arc Haul Ultra, Arc Zip Ultra, and the discontinued Arc Air and Arc Air Zip packs.
When a stay replacement makes sense
Replace your pre-curved arc stay if it is bent, cracked, or no longer holds its curve. A damaged stay can change how the pack carries weight, so it is worth fixing before a trip. The stay is the vertical carbon fiber piece that connects to the backpack by sliding into webbing pockets at the top and bottom of the pack. If you notice the pack sitting differently or the frame feeling less supportive, inspect the stay first.
Check the holster inserts before you install a new stay
The webbing pockets each contain a stay holster insert that covers the ends of the stay to help prevent them from punching through the pockets. These inserts have metal sandwiched inside, which makes them difficult to wear through, but they are replaceable and should be checked after 500–1,000 miles of use. If an insert is missing, cracked, or worn thin, replace it at the same time as the stay. Skipping this step can let the new stay damage the pocket.
Step-by-step stay replacement
- Remove the old stay: Slide the old stay out of the top webbing pocket, then out of the bottom pocket. Pull gently and keep the stay straight as it comes out. If the stay feels stuck, check for a bent end or a twisted pocket before pulling harder.
- Inspect the holster inserts: Look inside both webbing pockets for the stay holster inserts. Check for cracks, missing pieces, or a worn-through surface. If either insert is worn or missing, replace it now. The inserts have metal inside and are designed to be difficult to wear through, but they should be checked after 500–1,000 miles.
- Install the new holster inserts (if needed): Slide a new insert into each webbing pocket so it sits flat and covers the end of the stay path. Make sure the insert is fully seated and not folded over. A folded insert will not protect the pocket.
- Insert the new pre-curved stay: Slide the new stay into the bottom pocket first, then guide it into the top pocket. Push until it seats fully at both ends. The stay should slide in smoothly. If it binds, check that the holster inserts are aligned and not twisted.
- Check the fit: Confirm the stay is fully seated and the pockets are not stretched or distorted. Give the pack a gentle shake to make sure the stay does not shift. A properly seated stay will not move when you lift the pack by the frame.
Parts that work together
- Replacement Stay Holster Insert: The stay holster insert covers the ends of the stay to help prevent them from punching through the webbing pockets. It has metal sandwiched inside, making it difficult to wear through, and is replaceable. If your inserts are worn or missing, the new stay can wear through the pocket fabric. Replace them during the same repair.
- Replacement Pre-curved Arc Stay - Medium 20": The Replacement Pre-curved Arc Stay - Medium 20" fits Arc Haul Ultra, Arc Zip Ultra, and discontinued Arc Air and Arc Air Zip backpacks. Confirm your pack model before ordering. The 20-inch medium stay is the correct length for these models.
