Kreft Moto AER48 with Revalve Control

Maximum performance and versatility


Air spring failures are known to occur on the AER48, but don't rush out and buy a coil spring kit.  We have a fix, and we install it as part of every revalve.

Stock AER48 Fork

Kreft Moto has identified the following performance issues with the stock AER fork:

  • Air spring failures.  The fork can become "locked" halfway down in the travel.
  • Hyper-progressive spring curve.  AER48 relies largely on spring force to control travel usage and prevent bottoming.  While the fork has excellent bottoming resistance, this approach has drawbacks.  Spring force is position-sensitive, not speed-sensitive, so the fork exerts the same force at a given point in the travel regardless of the size of the bump.  Shim-controlled valves have the special ability to create a damping force proportional to the impact force, which is a great advantage in dissipating the energy most efficiently – which is to say, in the plushest way possible.  This is why AER48 feels plush at the top of the stroke, but harsh deeper in the travel. 
  • Rides too high in the stroke.  For the reasons described above, AER48 needs to ride high in the stroke to feel compliant.  However, the excessively tall ride height causes poor cornering traction, inaccurate line tracking, and an unsettled, "dancy" feel at the front wheel.
  • Oversimplified mid-valve.  AER48 uses a check spring type mid-valve in place of a traditional shim stack.  A single wave spring and check shim controls fluid flow through the valve.  This configuration reduces assembly time, but also reduces consistency, durability, and our ability to tune the valve.  It also contributes to a "blow-off" feel that makes the fork less sensitive to small bumps but use travel rapidly on larger impacts (again, relying on the air spring to control travel usage).

AER Spring Force
Before and After Kreft Modification

The stock air spring has too much progression in the second half of the stroke.  We modify the spring curve to mimic a coil-sprung fork.

Our Solution

Kreft Moto’s performance tuning for the WP AER48 includes the following improvements:

  • New air spring piston seal.  Our seal design and material eliminates air spring failures.
  • Linear spring curve.  Modification of the air spring element makes the air spring curve mirror a coil-sprung fork.
  • Neutral ride height.  Our revised spring curve and damping modification allows us to specify lower air pressures and create a more free-moving feel in the initial stroke. The added negative travel enhances traction on rough surfaces by helping the wheel remain in contact with the ground.  It also improves cornering confidence with a reliable turn-in feel and calm, "no-hands" line tracking.
  • Refined mid-valve.  By replacing the check shim with a traditional multi-layer shim stack tuned to our specifications, we can control compression damping with much greater precision.
  • Revalve Control.  A revolutionary external revalve system.

Revalve Control

Kreft Moto's AER48 brings with it a revolutionary new suspension technology called Revalve Control.  This technology makes it possible to alter the fork's shim valving stiffness by means of an external adjustment.  Riders have long wished for "external revalve" system, and this is it – the first and only motorcycle fork with that capability.  Revalve Control provides riders with two key advantages never before available:

  • Terrain Versatility
  • Insight

Terrain Versatility
The obvious benefit of being able to revalve your suspension in 15 seconds is access to a properly tuned suspension valving to match almost any terrain or soil condition.  While traditional suspension "ciickers" are good for fine-tuning, they are not capable of substantial changes to the damping curve.  Revalve Control can completely transform the fork – from enduro to MX, or from rocks to sand, or from beginner to pro – with just a 12mm wrench.

The other benefit of Revalve Control is the opportunity to experience and identify your true suspension preferences.  Professional riders work on-on-one with a suspension tuner to hone in on the performance characteristics that help them ride with the greatest confidence and control.  While very few of us have that luxury, Revalve Control places the same power in the hands of any rider with a KTM.  Even the pros have to wait an hour for a valving adjustment – a rider with Revalve Control can test 10 different settings back to back in a matter of minutes. 

As a suspension tuner, the hardest part of my job is interpreting the customer's comments into a valving setting that aligns with his desired riding experience.  Many customers have trouble articulating the suspension feel they are looking for, or in other cases the tuner develops an inaccurate picture of the rider's terrain, skill level, and riding style.  Bothscenarios result in a flawed suspension setting.  Revalve Control is forgiving of this difficulty.  For example, if Kreft Moto's original setting proves to be less than ideal, Revalve Control gives us tremendous power to resolve the complaint from a distance.




  • Kreft Moto's AER48 Revalve Control system with independent compression, rebound, and Revalve Control adjusters
  • Replacement of air spring piston seal with a more reliable design
  • Air spring modification for a more linear spring curve - like a coil spring fork
  • Nitrogen-charged air spring element for pressure stability
  • Custom valving setting prepared by Adam Krefting for each individual customer
  • Cleaning, inspection, and replacement of wear parts where required
  • Revalve Control settings table - a guide to tuning your suspension for optimal performance in different conditions

Optional Performance Upgrades

Applicable Models

  • 2016.5 KTM 450 SX-F Factory Edition
  • 2017 - 2018 KTM SX, SX-F, XC, & XC-F
  • 2017 - 2018 Husqvarna TC, TX, FC & FX

This assembly forms the heart of Kreft Moto's AER48 Revalve Control system.

Silent and durable nitrile top-out bumper.

Concentric Revalve Control and rebound adjusters.  The standard compression clicker is still located on the fork cap.


AER48 Revalve Control Adjustment Range

AER48 Stock Compression Adjustment Range

Revalve Control determines the shape and position of the damping curve (click for larger view).

The stock compression adjuster is retained for fine-tuning of low-speed compression damping (click for larger view).