Those are the spring numbers - they are variable rate springs
- PDS 6 = 7.1-9.0kg/mm 260mm length
- PDS 7 = 7.6-9.5kg/mm 260mm length
You should set up the springs for the same amount of static sag, the rider sag will differ. There is a lot of difference of opinion on this, I'll repeat what I have heard elsewhere (people call this the golden rule):
Static Sag:
1. Bike on stand, rear wheel hanging down. (Call this base measurement)
2. Push down on the tire to overcome the top out spring - should be about 8-10mm
3. Bike off stand, sag with respect to base measurement
4. Add the numbers in step 2 and 3 together, should be around 40-50mm
Note that with too much preload the internal top out spring can get compressed causing handling problems.
Race Sag - measure the way you normally do. YOu should run about 120mm+ here.
Believe this is right, maybe try posting this in the Jeremy WIlkey forum, he is very familar with KTM