FAQ - Luftkappe

How does it actually work? It enlarges the negative air chamber to reduce the initial spring rate. This lets you run higher air pressure for more support in the middle and end of the stroke with improved sensitivity in the start of the stroke.
Does it work with MRP's Ramp Control cartridge? ROCKSHOX
Compatible configurations: Pike up to 140mm, Lyrik/Yari up to 160mm
Incompatible configurations: Pike at 150mm or more, Lyrik/Yari at 170mm or more. These configurations cause interference between the Luftkappe and the Ramp Control cartridge.

FOX
Generally speaking no. If you are running your fork at least 30mm shorter than its maximum available travel, then yes.
Shouldn't I just buy a new fork instead? Um, if you want, they're about the same price as the Luftkappe... give or take a factor of 10!
What parts does it actually replace in the air spring? ROCKSHOX - It replaces only the plastic piston itself. You reuse your air shaft and seal head, as well as the piston bolt (except for 2018 Pikes, in which the piston bolt is replaced). The kit includes new seals for everything you may want to replace on that assembly (piston dynamic seals, piston bolt o-ring, dynamic shaft o-ring, seal head outer o-ring).

FOX - It replaces the plastic piston itself, and the rubber topout bumper in the 34s is removed but not replaced (36 topout assembly is unchanged). You reuse your air shaft, though the 34NA2 kit comes with a replacement low friction, low profile sealhead comparable in size to the stock 2018 Evol sealhead. This is also why the NA2 kit is more expensive than the other two - it's basically a 2018 Factory update on top of a Luftkappe.
What about 2018 Debonair? Does that make the Luftkappe redundant? For 2018, the Pike's Solo Air spring was updated to be more similar to the Lyrik/Yari, which had a larger negative chamber than the Pike. Lyrik/Yari were essentially unchanged except the shape of the topout bumper. All of them were given the "Debonair" name even though only one of them changed substantially. 2018 Pikes, Lyriks and Yaris benefit every bit as much from the Luftkappe as the previous generations.
What about 2019+ and 2021+ Debonair? Does that make the Luftkappe redundant? For 2019, Rockshox introduced a second (B1) Debonair version, with an enlarged negative chamber. For 2021, they introduced a third (C1) Debonair version, with a smaller negative chamber. Neither of these had as large of a negative chamber as the Luftkappe, and neither of them are compatible with the Luftkappe - see the Compatibility tab for information. The B1 Debonair air shafts do work well with the Secus however!
Who is this NOT suited for? The Luftkappe is outright superior to the stock air spring for nearly everyone, however there are a few cases where it might not be for you:
- If you run a Yari (not Lyrik) at 180mm or a Pike at 160mm, it will be quite progressive. You may well like it more than stock anyway, but you may also find it hard to use the last 5-10mm of travel - if this would bother you then have a think about it first. At any lower travels, it will be fine.
- If you run your 36 at 180mm, it will be quite progressive. You may like it, but you may also find it hard to use the last 5-10mm of travel - if this would bother you then have a think about it first. At 170mm and below it will be fine.
- If you like running really low sag for some reason. The Luftkappe runs more sag than the stock fork, but is firmer in the mid stroke - similar to a coil fork, but with ending-stroke ramp up to prevent harsh bottoming. If you're the kind of person who wants the fork to run 5% sag, this isn't for you. We could point out that a setup like that probably just means your handlebars are set too low and you're compensating with oversprung suspension, but we aren't here to judge you, so maybe just don't buy it.
- If you're anal about your fork having an exact (but rounded-to-the-nearest-10mm) amount of travel. Because the Luftkappe balances forces at a pneumatic topout, the force right around topout is very low (literally zero other than friction), meaning the weight of the bike alone will cause it to sag a few millimetres. Your car's suspension sags under the vehicle's own weight, so should your bike - unless it was so sticky, overly stiff or over-preloaded that 10kg of bike weight wasn't enough to cause your suspension to move at all, of course. If the idea of only having an apparent 148mm out of a 150mm fork is a big deal for you, stick with the stock fork.