Reply to thread

Message: [QUOTE="RM_guy, post: 24441, member: 20652"] I hope I’m not getting in over my head but here it goes. I understand spring design but my understanding of how it works as a suspension component on a dirt dike may be a bit shaky. Spring rate is roughly based on the flex modulus (springiness) and diameter of the wire. The units for spring rate are pounds/inch (or kg/mm). This means it takes ‘x’ pounds to compress ‘y’ inches. The length of the spring determines how much total load the spring can take for any particular spring rate. A spring with a rate of 10 lb/in would need 100 lbs to compress it 10 inches. To change the compressing force to 200 lbs at 10 inches you would have to increase the spring rate (via the wire diameter) to 20 lb/in. For a particular shock, any optional springs would have to be the same length in order to allow the shock to fully stroke before the spring bottoms out (coils come in contact with each other-which should not be allowed to happen in an optimum design). As far as I know the only optional springs would be variations in the spring weight (wire diameter), not length. It might be confusing when sag and spring preload is involved. In my example above of a 10lb/in spring, at free length it would take 10 lbs to compress it 1 inch. If it was preloaded by 1 inch to begin with (via the shock spring adjusters) it would now take 20 lbs to compress it an additional inch. This makes the spring stiffer and allows it to support a heavier rider and reduce sag. It doesn’t change the spring rate because that is controlled by the wire diameter. When the spring is preloaded it looks shorter but it is due to the extra compression, it is in an area the has more force. Remember, the further you compress the spring, the more force you need. As far as the weight of the spring, it is a balance between reliability, as the springs is compressed a zillion times, and weight. It is important that the fatigue stress of the wire material is not exceeded. In general less material makes it less reliable. I would just as soon accept the extra weight and keep it reliable. I hope I didn’t make this more confusing than it already is. I did skim over some of the more technical details. Feel free to blast me [img]http://dirtrider.net/ubb2/smile.gif[/img] ------------------ I don’t have a riding problem...I ride, I fall down...NO PROBLEM!! [/QUOTE]

Verification: Which ocean is California closest to?