Can you upgrade the previous-model SID or the SID SL with the new DebonAir+ spring? No, due to chassis updates, SID’s DebonAir+ air spring is not backward-compatible with older SID models or any SID SL model. Related articles Can I change the travel of my SID/SID SL fork? Are Bottomless Tokens available for SID and SID SL? What is the weight difference between the 2021 and 2024 SID/SID SL models? What are the benefits of the new TwistLoc Ultimate remote? I have a vintage RockShox suspension fork. Can I still get spare parts?