It all started with my new bike and its new Fox 36. After substantial tweaking and testing, I got it tuned up about as good as I could get it. On the medium-to-big impacts, the fork was great. It was like landing into a pit of marshmallows.
Off the top, things were not quite as nice. Little bumps seemed unnecessarily harsh. Fast and stuttery chunk was downright unpleasant. The fork wasn't unrideable, but I wanted it better. I didn't want to buy a different fork. I didn't want to convert it to coil. There are a lot of "claims" about how the Luftkappe can improve small bump compliance, but they seem too good to be true.
Having no other feasible options, I threw down $120 for a little chunk of aluminum and plastic. Installation is not much different than doing a lower service on your fork. They say a special tool is needed to remove the original piston. I made one, but probably could have got by with a hammer and drift.
Attached below is a picture from Vorsprung. It shows the Luftkappe and an original air piston. This fits inside your stanchion. The volume in between the aluminum bushing and the quad-ring on the piston is the negative air chamber. The area to the right, above the piston, is the positive side that you pressurize with your shock pump. The Luftkappe is hollow and allows air to enter from the negative side. It increases the size of the negative air chamber by about 35%, I'd guess. The Luftkappe takes up space on the positive side of the piston, the equivalent of about two volume spacers. Generally, you remove two spacers when you install the Luftkappe.
The increased negative volume results in a lower rate of pressure change at the initial part of the stroke, allowing for a more compliant feel. If the Luftkappe only increased the negative volume, the result would be a tendency to blow through all the travel on the bigger hits. But but the Luftkappe also decreases the volume on the positive side, so the spring rate increases more rapidly. The result is more mid and final support.
How does it ride?
The first thing I noticed was that the small bumps seemed less abrupt. Where the benefits of the Luftkappe became most evident were on the fast stuttery sections with medium-sized chunk. It's as if the harshest parts of the chatter were smoothed out, or rounded off. Imagine a saw blade with sharp v points, and then they're rounded off. That's how the fork now feels.
The other effect is how the bike now turns. Imagine leaning it into a fast turn, pushing hard, and every little bump wants to start the tire skipping over the pebbles and send you into a slide. The increased compliance afforded by the Luftkappe keeps the tire stuck to the ground, allowing me to push harder into turns.
Bigger hits seemed good, but I couldn't tell much difference. More testing is needed on more rugged trails, but I'm already certain that the cash thrown at the Luftkappe was money well spent.
Off the top, things were not quite as nice. Little bumps seemed unnecessarily harsh. Fast and stuttery chunk was downright unpleasant. The fork wasn't unrideable, but I wanted it better. I didn't want to buy a different fork. I didn't want to convert it to coil. There are a lot of "claims" about how the Luftkappe can improve small bump compliance, but they seem too good to be true.
Having no other feasible options, I threw down $120 for a little chunk of aluminum and plastic. Installation is not much different than doing a lower service on your fork. They say a special tool is needed to remove the original piston. I made one, but probably could have got by with a hammer and drift.
Attached below is a picture from Vorsprung. It shows the Luftkappe and an original air piston. This fits inside your stanchion. The volume in between the aluminum bushing and the quad-ring on the piston is the negative air chamber. The area to the right, above the piston, is the positive side that you pressurize with your shock pump. The Luftkappe is hollow and allows air to enter from the negative side. It increases the size of the negative air chamber by about 35%, I'd guess. The Luftkappe takes up space on the positive side of the piston, the equivalent of about two volume spacers. Generally, you remove two spacers when you install the Luftkappe.
The increased negative volume results in a lower rate of pressure change at the initial part of the stroke, allowing for a more compliant feel. If the Luftkappe only increased the negative volume, the result would be a tendency to blow through all the travel on the bigger hits. But but the Luftkappe also decreases the volume on the positive side, so the spring rate increases more rapidly. The result is more mid and final support.
How does it ride?
The first thing I noticed was that the small bumps seemed less abrupt. Where the benefits of the Luftkappe became most evident were on the fast stuttery sections with medium-sized chunk. It's as if the harshest parts of the chatter were smoothed out, or rounded off. Imagine a saw blade with sharp v points, and then they're rounded off. That's how the fork now feels.
The other effect is how the bike now turns. Imagine leaning it into a fast turn, pushing hard, and every little bump wants to start the tire skipping over the pebbles and send you into a slide. The increased compliance afforded by the Luftkappe keeps the tire stuck to the ground, allowing me to push harder into turns.
Bigger hits seemed good, but I couldn't tell much difference. More testing is needed on more rugged trails, but I'm already certain that the cash thrown at the Luftkappe was money well spent.
