KTM - PDS SHOCK SYSTEM
There are a lot of misconceptions about the KTM PDS linkless system. Let's clear the air. Paul Thede

1. Why did KTM eliminate the linkage?
   My guess - simplicity, less cost (no linkage), easier maintenance, and it's different.
2. Why does the PDS System use progressive springs?
   The lack of a linkage makes the KTM PDS the least progressive of all the popular dirt bikes. To make the ride more progressive the springs MUST be progressively wound. In an effort to make the damping more progressive the WP PDS damping system uses two pistons .
3. Why do after-market suspension companies recommend straight rate springs?
   I'm not really sure. It may be because there has not been much of a selection of progressively wound springs available. Perhaps it is because the progressively wound springs are pretty expensive or it could be because of a lack of information about the leverage ratio curves.
   

• Notice that the KTM has 75 kg (165 lb) less bottoming spring force than the CR 250. This means the KTM is down a whopping 20% in bottoming spring force.
• One of the typical after-market mods for the KTM PDS shocks is the use of a straight-rate spring. This theory actually provides about 30 kg (66 lbs) (almost 30%) less bottoming resistance than the stock KTM spring, while actually having more stiffness, and therefore more harshness in the middle of the stroke.
• The Race Tech P20 progressive spring force curve is actually more progressive than the stock spring and very similar to the well liked force curve of the CR 250
  
  

A High Performance Spring has a high stiffness to mass ratio meaning it is light weight for a particular rate. Made from Chrome Silicon Spring Steel, shot peened, heat treated and pre-set (no sacking).

KTM 125cc - 525cc SRSP 6326 Series P15 / P20 / P25 - $149.99
KTM 65cc - SRSP 4822 Series P20 / P25 - $149.99

What is a Race Tech P15, P20, and P25 Spring Rate?
These are Race Tech's answer to the linkless system to make it dramatically more progressive than any of the stock springs. We called them P15, P20, and P25 so you wouldn't get confused with WP's PDS1 through PDS8. The rates get stiffer as the numbers go higher.

Spring	125-200cc	250-300cc	450-525cc
SRSP 6326P15	Less than 150 lbs	Less than 140 lbs	Less than 130 lbs
SRSP 6326P20	145-195 lbs	135-185 lbs	125-175 lbs
SRSP 6326P25	Greater than 190 lbs	Greater than 180 lbs	Greater than 170 lbs
Mini Spring	65cc
SRSP 4822P20	Up to 80 lbs
SRSP 4822P25	75 lbs or greater

Why does the Gold Valve work so well on the KTM's?
The other reason the PDS system is so harsh is the way the damping works. The PDS System uses two pistons in an attempt to make more compression damping as it gets closer to bottoming. They feed the oil to the Primary piston through a hollow damping rod. This oil path is far too restrictive and won't flow enough oil, creating a harsh spike on high-speed hits like square edge bumps, roots, rocks, etc.
The Gold Valve System for the PDS has much larger compression ports allowing damping control to be created by the valving. This takes advantage of restructured compression damping on the Secondary piston that is allowed to open on those high-speed hits. This volume of oil is added to the flow from the center of the hollow shaft and solves the restrictive problem.
The result is a much plusher ride with excellent bottoming resistance

Bolt-on shock valving system that improves control, traction, performance and bottoming resistance. Kit includes Complete Instructions, Shock Gold Valve Piston, Valving Shims, Valving Charts, a "Technical Edge Shock Maintenance and Gold Valve Installation Video" for ease of installation and access to Race Tech's proprietary DVS suspension set-up database.

SMGV 5041 - 125cc-525cc - $149.99
SMGV 3602 - 65cc - $159.99

The Race Tech KTM Bladder Cap Kit makes rebuilding WP shocks easier. The Bladder Cap Kit converts the stock piston type reservoir to a "state-of-the-art" Bladder Reservoir like the factory Showa and KYB's. The Race Tech KTM Bladder Kit allows the shock to be filled with nitrogen with a
regular Schrader Chuck.

SWBL 01 46mm WP PDS (99-02 Big Bikes)
SWBL 02 52mm WP PDS (03 Big Bikes)
SWBL 03 52mm WP PDS (03 85cc)

The standard KTM WP PDS collars have been known to break and can only be adjusted in full turn increments. The Race Tech KTM Double Locking Spring Collars are strong and can be locked in any position. Available for big bikes only.

SWSC PDS50 $49.99