KX85 Shock Spring ????

[superchip73]

Hi, I'm new here and have a stupid question. My son rides a 03 KX85 and weights 70 pds, the stock shock spring was 4.7kg and was to stiff, so I changed it out with a 4.3kg (Race Tech) and the sags numbers showed that spring as being to stiff (75mm rider sag, 39mm static or free sag). I then put in a 3.8kg spring and my sag is 74mm rider and 30mm static.

My question is, how come my sag numbers are not reflecting these big changes in spring weights. I would like to get the sag to 80mm rider and 20-25mm static sag, do I get a 3.4kg spring or am I over looking something.

Thanks

 

[terry hay]

Superchip
I haven't performed a leverage ratio curve on a KX85 but the linkage could be part of the reason you get so much static sag. I would have thought the 3.8kg spring would be too light. Personally I too would have gone for the 4.3 spring. Still the proof is in the pudding. Try the two of them and see which one your rider prefers. You may also have some drag in the pivot bearings throwing out your measurements. A good dose of waterproof grease will sort that out.
Regards
Terry Hay

 

[superchip73]

Thanks Terry, I have gone through the suspension and regreased, all parts work smoothly. I'm going to take your advice and run the 3.8 against the 4.3, maybe the kx85 suspension just likes to throw a lot of static sag.

Thanks again