Vorsprung Luftkappe

Over the past decade air suspension has advanced in leaps and bounds. From simplifying assemblies for reduced static friction to cramming chucks of solid plastic underneath the top cap to fix harsh bottom outs, companies have put heaps of time into making air suspension the best it can be. And these engineers haven’t stopped there. The refining ‘flavor of the week’ (or past year or two) has been focused on the relationship between the positive and negative air spring compartments. FOX came out with the EVOL air spring in 2018 which took volume from the positive side and moved it into the negative side. The following production year RockShox did the same thing with their revamped Lyrik and BoXXer forks. Needless to say, this made for a very noticeable improvement in small bump sensitivity and made the initial stroke of the fork much smoother.

What if you want that same buttery-smooth feeling but can’t afford a $1,000+ top of the line 2019 FOX 36 Float Factory GRIP 2 EVOL or a 2019 RockShox Lyrik Charger 2 RC2 DebonAir fork? What if you’re a dentist and want to make that brand new 2019 fork even smoother? That’s where Vorsprung Suspension comes to the table. They make a product called Luftkappe which supposedly improves the small bump sensitivity and suppleness of your fork even more by robbing from the rich (positive chamber) and giving to the poor (negative chamber), kind of like a Robin Hood for your front suspension. We've had one out of the trails to see if it really made a difference - here is what we found.

Vorsprung Luftkappe Highlights

• Larger negative air chamber air spring assembly
• Retains volume spacer compatibility
• Works with the following FOX models:
  - 36 Float Evol (2018+)
  - 34 Float Evol (2018+)
  - 34 Float NA2 (2016-17)
• Works with the following RockShoxx models:
  - Lyrik/Yari Solo Air and Debonair (2016-18+)
  - Pike 29+ Solo Air (2018)
  - Pike Debonair (2018+)
  - Pike Solo Air (2014-17)
• MSRP: Kits starting at $105 USD for FOX 34 and 36 models // $85 USD for RockShox models
• Optional tools available for self-install

Example Spring Curve Change for FOX 34 Fork

Initial Impressions

Taking the Luftkappe out of the box, we found it to be fairly minimal: Luftkappe piston head, roll pin, roll pin tool (which is $22 USD extra), and a few stickers. Printed instructions are not provided, but the Vorsprung website provides a very detailed and thorough installation video. Gathering our tools, slick honey grease, and Loctite it took us an additional 10 minutes to get the item installed during a fork rebuild. Timing the install of a Luftkappe with a basic seal service is highly recommend as many of the steps are the same.

Since we were installing the Luftkappe on a FOX 36 platform, the company was adamant about making sure we had the 2019 top-out bumper and not the 2018 top-out bumper which was somewhat under-engineered and could often result in a harsh top-out feeling – installing a Luftkappe on the older 2018 air shaft assembly makes the top-out even worse. After putting the fork back together, we were eager to see how it performed out on the trail.

On The Trail

Before we begin, PLEASE NOTE: In order for our tester to run the Luftkappe he replaced the standard CSU on his Marzocchi Z1 with 36 Performance Elite uppers. The stanchions found on the Z1 are thicker and will not work with a 36 Luftkappe configuration.

Throwing a leg over the saddle and getting the rubber on dirt, we instantly noticed a difference in how supple our front suspension had become. With the latest EVOL air spring installed we were already quite impressed with how the fork rode compared to the prior (2017) air spring. This EVOL update consists of fewer O-rings and a larger negative air chamber which functions with less friction and provides an overall more supple ride, and after this upgrade the latest generation of the FOX 36 is considered one of the best-feeling forks on the market today –with good reason. Installing the Vorsprung Luftkappe in this already impressive fork made things even smoother but it also allowed us to address other areas of the fork’s performance which will be covered below.

On the trail, we used less brake because the fork ate up so much of the high speed trail chatter that would previously unsettle us. Because so much of the subtle jarring was muted, we found ourselves rolling into technical sections of trail with way more speed than we normally would. The Luftkappe made the bike ride smoother which increased our confidence. Ultimately, blazing through rough terrain we really felt like the bike’s performance reached a whole new level.

We found that the Lufkappe balanced out the initial and mid stroke in a way we wanted but never could get with the stock air spring – even after the EVOL upgrade.

When setting up the stock fork, we prioritized a supple initial stroke. We ran the pressure about 10 PSI lower than recommended and installed extra volume spacers for bottom-out control. This made for a less than supportive mid-stroke and the fork would ride quite low in its travel, particularly while hitting the front brake on descents.

After dozens of rides on familiar trails we noticed two things after installing the Luftkappe:

1. The fork offered much plusher ride. With the Luftkappe installed the fork almost became too supple and as a result we had to tweak our initial setup (adding 10-15 PSI of main air spring pressure). This gave us a smoother-than-stock initial stroke but also significantly improved the mid-stroke support that had been sacrificed earlier.
2. The fork had more significant ramp-up to it. The fork’s travel was never fully used so we removed one of the two volume spacers previously installed and things got much better.

To recap, we found that the Lufkappe balanced out the initial and mid stroke in a way we wanted but never could get with the stock air spring – even after the EVOL upgrade. With the stock EVOL fork, we were able to get the off-the-top action we were looking for, and we could control bottom-out with volume spacers, but all that came at the expense of good mid-stroke support, which at the time was a trade-off we were happy to make. However, the Luftkappe blends sensitive small-bump compliance, mid-stroke support, and bottom out resistance perfectly; pretty close to the holy grail of suspension performance - as good as the stock fork is, we no longer want to be without the Luftkappe.

Things That Could Be Improved

Vorsprung has made the Luftkappe available for two of the major fork manufactures (FOX and RockShox). Not everyone rides one of those two brand and those who don’t won’t be able to benefit from this product. It would be great to see the Luftkappe available for other brands that make mid-range to high-end suspension as well. As previously mentioned, we'd also love to see the roll-pin tool included in the price of the regular Luftkappe kit for FOX forks.

Long Term Durability

When it comes to durability, the Lufkappe has been completely problem-free during our entire testing period. The materials used appear to be high grade and the seals on the Luftkappe have held up nicely. We don’t anticipate any particular problems, but we will be keeping an eye on it to make sure nothing untoward pops up down the line.

What's The Bottom Line?

Vorsprung Suspension has produced some amazing products to take stock suspension and personalize it for the individual rider. Some are more specific, like Fractive fork tuning which adjusts damper valving while others are more generic like the Luftkappe air piston head. Although much less specific than custom suspension work, the Luftkappe made a huge difference in getting the most out of our fork by manipulating the characteristics of the air spring. It offers outstanding small bump compliance and helps balance out the entire travel of the fork. The Luftkappe is a great addition for the most current FOX and RockShox forks and is an absolute must for older versions which lack the increased negative air spring chambers. At a reasonable price point, we can confidently say you will not be disappointed with the performance improvement it brings.

Visit www.vorsprungsuspension.com for more details.

About The Reviewer

Lance Starling - Age: 30 // Years Riding: 17 // Height: 6'3" (1.91m) // Weight: 190-pounds (86.2kg)

Lance got his first mountain bike in 2001. Fast-forward 17 years and not a day has gone by that he hasn’t completely obsessed over the sport. This obsession has transformed him into a mountain bike guru whose love for picking apart components and gear is similar to a honey badger consuming king cobras. Nothing is left untouched. His playful riding style generally keeps him more in the air than on the ground and whatever tricks he lacks he makes up for with a good ol’ bar hump. Never at any time have consumers have had it so good and with over ten years in the industry as a certified mechanic and gear expert, Lance is devoted to helping those riders find the perfect gear to meet their needs.

Photos by Lance Starling