I just purchased a brand new 03 525sx and while i was in the process of setting shock sag i came to the conclusion the stock spring was to stiff for my 160 lbs.so I contacted mx- tech to find out the right spring rate for my weight and sure enough he told me the stock #7 was to hard for my weight and that the #6 spring is softer and should do the trick.Well after installing the new spring i came up with the same sag numbers as before the springs looked identical except for the numbers printed on the spring the #7 had 76-95/260 the new one had 71-90/260 are these spring rate numbers or batch numbers, Could different preloads cause this problems.
shock spring confusion
- Thread starter dirtroost
- Start date
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
- 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
- Thread starter
- #3
Man that is what i was trying to do hit those golden rule numbers but i can not seem to get close.Reducing the preload i end up with 56mm of static sag which gives me 113mm race sag.when i had more preload i had 50mm static and 100mm race sag,I thought the lighter spring would have put me in the ballpark but I guess my 162# weight is not enough to make the #6 spring work to the golden rule.It looks like I would have to go to the limp noodle spring to hit those numbers.By the way I'am having to divide by .04 to get the metric numbers I hope that's right.
marcusgunby
LIFETIME SPONSOR
- Jan 9, 2000
- 6,450
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Some pds springs dont measure as they say-so a pds 6 might be almost the same rate as a 7.
Radiator Ron
Member
- Dec 8, 2003
- 73
- 0
Just read in dirt rider last night use 10mm more race sag than jap bikes, the ktm will have a little more static sag than 25mm.
