DaveVato Posted June 7, 2007 Author Report Share Posted June 7, 2007 Good point firehead, I have thought about a bar instead of the spring, ha. But my 425 spring just arrived, I have to try that tonight. does anyone know the stock spring weight, if that is the correct term. Quote Link to comment Share on other sites More sharing options...
FireHead Posted June 7, 2007 Report Share Posted June 7, 2007 Good point firehead, I have thought about a bar instead of the spring, ha. But my 425 spring just arrived, I have to try that tonight. does anyone know the stock spring weight, if that is the correct term. Spring rate is the term that would be used when talking about your springs load carrying capacity. Obviously the OEM spring is progressively wound which mean that the spring rate varies during shock travel, but when specifying an aftermarket spring, they are generally defined buy an overall spring rate. I believe the OEM spring is 325lbs./in I am probably worng about that the more that i think about it. The largest Eibach srping you can put on an OEM shock without buying adapting collars is 475lbs./in. :geek: Quote Link to comment Share on other sites More sharing options...
DaveVato Posted June 7, 2007 Author Report Share Posted June 7, 2007 That is good stuff right there, thanks firehead! I should have gone for the 475, dang it! I am hosed tommy, hosed.... Quote Link to comment Share on other sites More sharing options...
Flash and Flare Posted June 8, 2007 Report Share Posted June 8, 2007 That is good stuff right there, thanks firehead! I should have gone for the 475, dang it! I am hosed tommy, hosed.... If I can find out what I need, I might be interested in buying that 425rate spring from ya. (if its to light for you) Anyone know what rate is needed for a 235lb person on a -2 swinger ? Quote Link to comment Share on other sites More sharing options...
RNBRAD Posted June 8, 2007 Report Share Posted June 8, 2007 I would still like to make sure that it is understood that adjusting preload on the shock does not increase the shocks ability to carry load. All it does is raise the bike frame higher off of the ground. Since a coil spring is basically just a funky torsion spring, the more you compress the spring upon itself, the more the coils bind. The spring may seem stiffer when you crank the preload down, but really all you are doing is compressing it so that the lighter progressive windings are bound and taken out of the working range of the shock, thus limiting your suspension travel. To be a biot sensational, you might as well just take the shock off and bolt in a solid bar in it's place if you are increasing spring preload to compensate for a longer swingarm or heavier rider. :geek: Spring preload does compensate for a heavier rider. That's how you adjust your ride height/sag. Preload will need to be increased with increased rider weight and gear weight to maintain "appropriate" ride height or sag. Also increasing preload "should" never decrease suspension travel. Your not bottoming the spring, your bottoming the bump stop against the shock body, even with preload set to maximum. At least on a shock that's built correctly. Quote Link to comment Share on other sites More sharing options...
FireHead Posted June 8, 2007 Report Share Posted June 8, 2007 Spring preload does compensate for a heavier rider. That's how you adjust your ride height/sag. Preload will need to be increased with increased rider weight and gear weight to maintain "appropriate" ride height or sag. Also increasing preload "should" never decrease suspension travel. Your not bottoming the spring, your bottoming the bump stop against the shock body, even with preload set to maximum. At least on a shock that's built correctly. I agree with the fact that preload adjustments are used to adjust sag and ride height. However, in no way does preload effect the ability of a suspension system to carry load. You can adjust how the bike sits statically with a fat person on it, but that suspension will perform the same as it did if you had not adjusted the preload for the fat guy. Force, direction, friction, and kinetics will all stay the same. Beyond that, when you indezx the spring lower on the shock body, you are esentially minimizing down travel of the suspension. Also, cranking down the preload beyond a certain point binds the coils of the spring. If adjusted too far, the coil windings will compress together and bind before the shock gets near the rubber bump. stop on the shock shaft. Quote Link to comment Share on other sites More sharing options...
FireHead Posted June 8, 2007 Report Share Posted June 8, 2007 If I can find out what I need, I might be interested in buying that 425rate spring from ya. (if its to light for you) Anyone know what rate is needed for a 235lb person on a -2 swinger ? Figuring that out is pretty simple trigonmetry. All you have to do is make a triangle and figure out what the motion ratio of your axle vs. Your shock is (how much the shock moves compared to your axle in a suspension cycle. As I madly finger my Bloackberry trying to reply to this, I am reminded of a web page I found that calculated it for you. Google atv and spring rate or suspension rate and you should be able to find it. If not, I will work out answer for you when I get home tonight. Quote Link to comment Share on other sites More sharing options...
Flash and Flare Posted June 8, 2007 Report Share Posted June 8, 2007 (edited) simple trigonometry. Is that some sort of a joke :biggrin: ????? If you come up with a # for me that would be great, but untill then I will try on do the plum bob, chalk line on the swing arm, laser level off the seat, projection deflection run out display on the garage wall theory. F&F Edited June 8, 2007 by Flash and Flare Quote Link to comment Share on other sites More sharing options...
Meat Posted June 8, 2007 Report Share Posted June 8, 2007 (edited) Flash and Flare !! how ya doin, long time - no see. Edited June 8, 2007 by Meat Quote Link to comment Share on other sites More sharing options...
FireHead Posted June 8, 2007 Report Share Posted June 8, 2007 Is that some sort of a joke :biggrin: ?????If you come up with a # for me that would be great, but untill then I will try on do the plum bob, chalk line on the swing arm, laser level off the seat, projection deflection run out display on the garage wall theory. F&F Ok, let's do this, you measure from the center of your swingarm bolt to the center of your rear axle, and I will do the rest. I am assuming your shock and linkage are still in the stock location. It would also hellp me to know rider weight, a guestimate of the weight of the rear of your bike (if you put scales under each rear wheel) and what sort of riding you are doing. I suppose without the background knowledge, the triangle is the only thing simple about the trigonometry. I some times leave out stuff when I am posting via my Blackberry. :geek: Quote Link to comment Share on other sites More sharing options...
MDS2106 Posted June 8, 2007 Report Share Posted June 8, 2007 By varying the position of the spring adjuster on the shock body,spring preload can be changed to best suit rider weight and riding conditions... Quote Link to comment Share on other sites More sharing options...
FireHead Posted June 9, 2007 Report Share Posted June 9, 2007 By varying the position of the spring adjuster on the shock body,spring preload can be changed to best suit rider weight and riding conditions... ....................I think that may be the most general, uninformative statement ever made. :ermm: Quote Link to comment Share on other sites More sharing options...
375hp banshees Posted June 9, 2007 Report Share Posted June 9, 2007 I agree with the fact that preload adjustments are used to adjust sag and ride height. However, in no way does preload effect the ability of a suspension system to carry load. You can adjust how the bike sits statically with a fat person on it, but that suspension will perform the same as it did if you had not adjusted the preload for the fat guy. Force, direction, friction, and kinetics will all stay the same. Beyond that, when you indezx the spring lower on the shock body, you are esentially minimizing down travel of the suspension. Also, cranking down the preload beyond a certain point binds the coils of the spring. If adjusted too far, the coil windings will compress together and bind before the shock gets near the rubber bump. stop on the shock shaft. so firehead, by making your spring shorter or longer installed, doesn't make any difference except for the ability to travel more before binding(because you make it sag to much as soon as you sit on it)...A 200lb rider w/ spring as tall as you can adjust it, will sag the spring at the same rate as A 200lb rider w/ the spring adjusted as short as it can be assuming it doesn't coil bind (bottom out) except ride hight or center of gravity (if that is the correct term) not being A smart, ass realy want to know Dave Quote Link to comment Share on other sites More sharing options...
dawarriorman Posted June 9, 2007 Report Share Posted June 9, 2007 (edited) so firehead, by making your spring shorter or longer installed, doesn't make any difference except for the ability to travel more before binding(because you make it sag to much as soon as you sit on it)...A 200lb rider w/ spring as tall as you can adjust it, will sag the spring at the same rate as A 200lb rider w/ the spring adjusted as short as it can be assuming it doesn't coil bind (bottom out) except ride hight or center of gravity (if that is the correct term) not being A smart, ass realy want to know Dave By shorter and taller you mean by adjusting preload right? (if you cut a spring, you change the spring rate). Assuming a linear rate spring (easiest to talk about) they have a certain spring rate (200 pounds per inch as an example). When the spring is uncompressed, it takes 200 lbs to compress that spring one inch. To compress it another inch, it takes another 200 lbs. So to compress that spring 2 inches takes 400 lbs. Now say that spring is on the shock. If it is compressed 1 inch due to preload, it will take 200 lbs of force before the shock will start to compress. If its compressed 3 inches due to preload it will take 600 lbs of force before the shock starts to move. Once it starts moving though, its still a 200lb/in spring. All the preload is doing is determing how far the shock is compressed when the machine is sitting still. With a heavier rider, you use more preload to achieve the same ride height. Therefore the shock will act the same for the heavier rider with more preload as it will for the lighter rider with less preload (this is only taking spring rate into account, not valving). That make any sense? Edit: as far as coil bind, It shouldn't happen as long as the people that made the shocks paid attention to what they were doing and used long enough springs. Edited June 9, 2007 by dawarriorman Quote Link to comment Share on other sites More sharing options...
FireHead Posted June 9, 2007 Report Share Posted June 9, 2007 so firehead, by making your spring shorter or longer installed, doesn't make any difference except for the ability to travel more before binding(because you make it sag to much as soon as you sit on it)...A 200lb rider w/ spring as tall as you can adjust it, will sag the spring at the same rate as A 200lb rider w/ the spring adjusted as short as it can be assuming it doesn't coil bind (bottom out) except ride hight or center of gravity (if that is the correct term) not being A smart, ass realy want to know Dave It is not so much that it travels more before binding..............you will always have the same amount of shock travel. It is that you are indexing the spring to the shock body. Basically you are changing the ratio of spring up travel available vs. shock up travel available or vice versa. I think the big hang up here is that you have to buy into the fact that adjusting preload does not change the the rate (load capacity) of the spring. If a person is going to aregue about that, then I cannot help them. It's a straight, black and white fact. However, if you do believe otherwise I have a magic carburetor that runs on water that I would like to sell you. Quote Link to comment Share on other sites More sharing options...
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