NEW REPLACEMENT
COIL SPRINGS 16/09 SHOCK ABSORBER, SUSPENSION, BRAKES, TOWBARS AND WHEEL ALIGNMENT SPECIALISTS
One of the most frequently asked questions (F.A.Q.) asked is “Why are the new replacement coil springs lower than the old units” and yet they are supposed to raise the car to a restored standard ride height. The free height of the new increased rate coil is somewhat important, but not as important as the “loaded ride height”. All Pedders coil springs are designed with a heavier rate. The rate for every coil for every car is designed very carefully and is calculated using a “load verses deflection” formula. In doing so, as the rate is higher, the coil will not deflect as much, so the starting height or the “free Length” will be shorter.
Replacement Coil Springs The factors that determine spring rate
There are three main elements to be taken into account when designing a coil spring: • Material size (Wire diameter).
• The amount of working coils. is “Why are the new replacement coil springs ked questions (F.A.Q.) asked The Mean diameter of the coil. yet they• are supposed to raise the car to a restored standard ride height.
Spring rate refers to the amount of weight needed to compress a spring a given distance (Example:500lb per inch).
To understand and properly check a spring for rate you need to know the factors that determine the rate of the reased rate coil is somewhat important, but not as important as the “loaded spring. Fortunately, there are only three things that affect spring rate, so there’s not that much to remember. springs Wire are designed diameter with a heavier rate. The rate for every coil for every car is calculated usingratea since “load verses deflection” In doing as the is is This affects greater diameter wire is strongerformula. than lesser diameter wire.so, So, when wirerate diameter increased, spring rate increases. t as much, so the starting height of the “free Length” will be shorter.
Mean diameter of spring
Mean diameter is the overall outside diameter of the spring less one wire diameter. When the mean diameter pring rate increases, the spring rate decreases.
Active coils
to be taken into account when designing a coil spring:
Determination of the number of active coils varies according to spring design. Count the total coils minus the top and bottom coil, as they are “locating” coils not “working coils. As the number of active coils increases, the spring rate decreases.
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heck a spring for rate you need to know the factors that determine the rate of
inear rate springs” have one defined spring rate per inch of deflection throughout most heir range ofrate travel. Forhave instance, ifdefined wedefined have aspring 350lb/inch linear rate spring thatthroughout is 16most “Linear rate springs” have one rate per inch of deflection most “Linear springs” have spring rate per inch of deflection throughout most “Linear rate springs” oneone defined spring rate per inch of deflection throughout hes long, it range will approximately 350lb to deflect inch.linear The next inch of of their range of travel. For instance, ifhave we a1350lb/inch linear rate spring is 16 their of travel. instance, if we have a it350lb/inch linear spring is 16 of of their range oftake travel. ForFor instance, if we ahave 350lb/inch raterate spring thatthat isthat 16 inches long, it take will take approximately 350lb toinch deflect itinch. 1 inch. The next lection will take 350lb of load and the next will take anof of inches long, itanother will take approximately 350lb to deflect itinch. 1deflection The next inch inches long, it will approximately 350lb toREPLACEMENT deflect it 1of The next inch ofinch NEW deflection will take another 350lb ofspring load and the next inch of deflection will take itional 350lb of load (and so350lb on until the goes solid). At this point there will deflection will take another 350lb load and the next inch of deflection will take anbean deflection will take another of of load and the next inch of deflection will take an of load (and on until the spring goes solid). At this point there 0lb ofadditional load 350lb on350lb a350lb 16 inch long spring that has now been compressed to 13” of loaded additional load (and so on until the spring goes solid). this point there will be be additional of of load (and so onso until the spring goes solid). At At this point there will bewill 1050lb of load on a 16 inch long spring that has now been compressed toof13” of loaded ng height. 1050lb load on a 16 inch long spring that has now been compressed of loaded 1050lb of of load on a 16 inch long spring that has now been compressed to to 13”13” loaded 16/09 spring height. spring height. spring height.
COIL SPRINGS
SHOCK ABSORBER, SUSPENSION, BRAKES, TOWBARS AND WHEEL ALIGNMENT SPECIALISTS
rogressive rate called “Variable Rate” springs. The purpose There aresprings” two basicare coilsometimes spring designs “Progressive rate springs” are sometimes called “Variable Rate” springs. The purpose “Progressive rate sometimes called “Variable Rate” springs. purpose “Progressive rate areare sometimes called “Variable Rate” springs. TheThe purpose non-linear springs issprings” tosprings” provide more compliance in the suspension over rough • Linear rate. of non-linear springs is provide to provide more compliance insuspension the suspension over rough non-linear springs is to more compliance in rates the suspension over rough of of non-linear springs is to provide more compliance in the over rough faces. These springs are designed with low initial spring but rapidly increase as • Progressive or Variable rate. surfaces. These springs are designed with low initial spring rates but rapidly increase surfaces. These springs are designed with low spring rapidly increase surfaces. These are designed with low initial butbut rapidly increase ratesprings springs” have one defined spring rate perinitial inchspring of deflection throughout spring is“Linear compressed. The theory is that this allows the carrates torates travel smoothly over as as as most their of travel.The ForThe instance, ifiswe a 350lb/inch linear rate spring the spring isrange compressed. theory ishave that this car tohandling travel smoothly over spring is compressed. theory that this allows the car to travel smoothly over thethe spring isof compressed. The theory that this allows the carthe togood travel smoothly over mps and road beistight enough toallows provide and that is 16imperfections inches long, it will but take still approximately 350lb to deflect it 1 inch. The next inch bumps and road imperfections still be tight enough to provide handling bumps and road but still be tight enough to provide good handling of deflection willimperfections take another 350lb ofbut load and the next inch ofthese willgood take bumps and road imperfections but still be tight enough todeflection provide handling and vent the chassis from bottoming out. Because of this, springs aregood popular in andand an additional 350lb of load (and so on until the spring goes solid). At this point there prevent the chassis from bottoming out. Because ofcompressed this, these springs are popular prevent the chassis from bottoming out. Because this, these springs are popular prevent the from out. Because of of this, these springs popular in in in will be chassis 1050lb of load onbottoming a 16 inch longfor spring that has now been to 13”are ofVariable rmarket lowering springs intended use on public roads. Progressive/ rate loaded spring height. Progressive/ Variable aftermarket lowering springs intended for on public roads. aftermarket springs intended for use on public roads. Progressive/ Variable aftermarket springs intended forare use onuse public roads. Progressive/ Variable rateraterate ngs are easy lowering tolowering spot because the springs not symmetrical. Typically, one end of “Progressive springs” are sometimes called “Variable Rate” springs. The purpose springs are easy to spot because the springs are not symmetrical. Typically, one springs are easy to spot because the springs are not symmetrical. Typically, one end of of springs easy torate spot because springs are not symmetrical. Typically, end ofend spring isofare wound the the other end with the more tightly wound endone being the non-lineartighter springs isthan to provide more compliance in the suspension over rough the spring is wound tighter than the other end with the more tightly wound end being the spring isThese wound tighter than the other end with the more tightly wound being spring is wound tighter the other end with the more tightly wound endend being thethe the surfaces. springs arethan designed with low initial spring rates but rapidly increase erthepart of the spring. As the spring is compressed, the soft coils on the tightly wound as part thepart is the compressed. The theory is that the carthe to travel smoothly softer spring. As the spring is allows compressed, the soft coils the tightly wound softer of the spring. the spring is this compressed, soft coils on the tightly wound part ofspring theof spring. AsAs the spring is compressed, the soft coils on theon tightly wound over bumps and roadinto imperfections but still be tight other. enough to provide good handling the rest of e softer will collapse, coming contact with each When this happens, side will collapse, coming into contact with each other. When this happens, the side will collapse, coming into contact with each other. When happens, rest of of and prevent thecoming chassis from bottoming out. Because ofother. this, these springs are side will collapse, into contact with each When thisthis happens, thethe rest ofrest spring starts compresslowering the coils with the larger pitch, has the higher rate. popularto in aftermarket springs intended for use on publicwhich roads. Progressive/ the spring starts toare compress the coils with the larger pitch, which has the higher spring starts to compress the coils with the larger pitch, which the higher rate.rate. thethe spring starts compress coils with the larger pitch, which hashas the higher rate. Variable rateto springs easythe to spot because the springs are not symmetrical.
Typically one end of the spring is wound tighter (coils closer together) than the other end. Because each individual coil compresses at the same rate when load is applied the coils which are wound closer together come into contact, starting with the end which is mounted the vehicle and as closer wound coils “close” on each ings thatcoilare designed totoinclude coils ofthedifferent diameter or are wound using a Springs that are designed to include coils different diameter or are wound using Springs that are designed to effectively include coils ofthedifferent or are wound using Springs that are designed to which include coils of of different diameter arespring wound using a a other they become inactive reduces number of diameter coils or in the eredtapered wire will also produce a progressive rate. increasing its rate. wire will also produce a progressive rate. tapered wire will also produce a progressive rate. tapered wire will also produce a progressive rate.
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e smaller mean diameter thetothe higher the coils raterate and the larger the diameter the The smaller mean diameter the higher the coils rate and the larger the mean diameter The smaller mean diameter higher the coils and larger themean mean diameter thethe the The smaller mean diameter the higher the coils rate and the larger mean diameter Springs that are designed include coils of different diameter orthe are wound using a the erlower the spring rate. tapered wire will also produce a progressive rate. lower spring rate. thethe spring rate. lower the spring rate. The smaller mean diameter the higher the coils rate and the larger the mean diameter the lower the spring rate.
Pedders Suspension coil spring manufacturing plant holds the internationally ders Suspension coilcoil spring manufacturing plant holds the internationally recognised Pedders Suspension coil spring manufacturing plant holds the internationally recognised Pedders Suspension spring manufacturing plant holds the internationally recognised Pedders Suspension coil spring manufacturing plant holds the internationally recognised recognised manufacturing quality standard of ISO 9001. nufacturing quality standard of ISO 9001. manufacturing quality standard of ISO 9001. manufacturing quality standard of ISO 9001. manufacturing quality standard of ISO 9001. What this means to the Pedders Suspension customers, is that they can be assured atWhat this means to the Pedders Suspension customers, is that can be they this means tosupplied thethe Suspension customers, is that can beassured assured they What this means to customers, is they that they can be assured theythey What this means toPedders the Pedders Suspension customers, isthey that they can be assured they are being aPedders product ofSuspension significantly high quality. being supplied a product of significantly high quality. areare being supplied a product of of significantly high quality. being supplied a product significantly high quality. are being supplied a product of significantly high quality.
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Straight advice, specialists you understand and...