Spring Lengths (Front & Rear Swapped?)
#1
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Location: Columbus, Ohio, United States
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Car Info: 2000 Impreza 2.5 RS Blue Ridge Pearl
Spring Lengths (Front & Rear Swapped?)
Hey All Knowing Scooby Wizards,
After 116,000 miles of abuse my stock springs and struts have had it. I just replaced them with KYB struts and Eibach springs.
I compressed the front springs and installed the top hardware. Decompressed and installed into the car. No probs. Looks good, camber was adjustable to the correct tolerances, rides good, etc.
For the rear I found that the spring didn't need compressed in order to install the top hardware. I continued on and installed them. The rear looks good, and after a few clunks when initially driving, they seem to have quieted down and it rides good.
Thinking back on my many hours of work, my question is this: could I have accidentally swapped the front and rear springs?
1. The front struts are longer than the rear struts, and this led me logically to believe that,
2. The tallest pair of springs should be placed on the longer struts (i.e. front).
Is this correct? Or did I goof?
After 116,000 miles of abuse my stock springs and struts have had it. I just replaced them with KYB struts and Eibach springs.
I compressed the front springs and installed the top hardware. Decompressed and installed into the car. No probs. Looks good, camber was adjustable to the correct tolerances, rides good, etc.
For the rear I found that the spring didn't need compressed in order to install the top hardware. I continued on and installed them. The rear looks good, and after a few clunks when initially driving, they seem to have quieted down and it rides good.
Thinking back on my many hours of work, my question is this: could I have accidentally swapped the front and rear springs?
1. The front struts are longer than the rear struts, and this led me logically to believe that,
2. The tallest pair of springs should be placed on the longer struts (i.e. front).
Is this correct? Or did I goof?
#3
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Car Info: 2000 Impreza 2.5 RS Blue Ridge Pearl
Originally Posted by scottzg
the springs can be swapped front to rear, unfortunately, i dont know if the rear strut is longer when fully extended.
However, the springs are different heights, and I'm assuming that the higher spring goes on the higher strut... ?
#4
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no that's not true. I just put the prodrive springs on my wrx and the short fat springs went up front and the the taller ones with more coils were for the rear. Prodrive springs are made by eibach so they should be similar. Mine said front and rear on them anyways. The springs shouldn't be swapped because of difference in drop and spring rate.
Last edited by lovesmysuby04; 06-25-2005 at 11:31 PM.
#5
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Originally Posted by lovesmysuby04
no that's not true. I just put the prodrive springs on my wrx and the short fat springs went up front and the the taller ones with more coils were for the rear. Prodrive springs are made by eibach so they should be similar. Mine said front and rear on them anyways. The springs shouldn't be swapped because of difference in drop and spring rate.
Anyone else want to confirm?
#6
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Originally Posted by lovesmysuby04
no that's not true. I just put the prodrive springs on my wrx and the short fat springs went up front and the the taller ones with more coils were for the rear. Prodrive springs are made by eibach so they should be similar. Mine said front and rear on them anyways. The springs shouldn't be swapped because of difference in drop and spring rate.
Thats how my SPT's (Eibach) were, here's some info to prove he's right.
2002-2003 WRX Sedan Performance Spring Set
Q. What is the "Free-Length"?
A. Front: 253 mm, Rear: 308 mm
Q. Who manufactures them for Subaru?
A. Eibach
Info taken from here http://www.spt.subaru.com/microsites...trim=WRX+SEDAN.
Do the wheel gaps look way off?
#7
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Car Info: 2000 Impreza 2.5 RS Blue Ridge Pearl
Oh, this does not make my day. The rear wheel-well gap looks right.
Today at 4 AM on my way driving the car to the airport I got to thinking again.
* The front struts are longer than the rear struts
* One pair of springs is taller than the other pair
Keeping this in mind, if the short springs had no tension (actually a decent gap) on the short struts, then the short springs would have even a LARGER gap on the long struts (front).
Now, I realize the front of the car is probably at least twice as heavy as the rear, so the shocks will never be fully extended, BUT, this still leaves me uneasy. In *MY* logic I'm thinking that *SINCE* the front is so much heavier that I would *WANT* the tall springs (hence more potential energy) on the longer struts in the front...
I was just originally worried that by having the tall springs installed on the front that I was putting undue extra compression on them which would cause premature failure. HOWEVER, since the rear struts are SHORTER than the front, by placing these tall springs on the shorter struts, the constance compression would also be present (and I would have no tension and quite a large free gap on the front struts by installing the short springs). Of course the rear of the car is lighter, so the constant compression force would not be nearly as great as the front, but it was quite a lot of compression I had to use to get the tall springs installed on the front/long struts in the first place and by compressing them even more to get them on the rear/short struts might even be hazardous to my health!
Is this current configuration, with the tall springs on the long struts, a safety hazard in any way? I do not see how it could be, because of my stated facts above, but I am driving to Ontario this weekend for a family renunion and would hate to have to tow my car back to Ohio...
Someone please explain the flaw in my logic...
Today at 4 AM on my way driving the car to the airport I got to thinking again.
* The front struts are longer than the rear struts
* One pair of springs is taller than the other pair
Keeping this in mind, if the short springs had no tension (actually a decent gap) on the short struts, then the short springs would have even a LARGER gap on the long struts (front).
Now, I realize the front of the car is probably at least twice as heavy as the rear, so the shocks will never be fully extended, BUT, this still leaves me uneasy. In *MY* logic I'm thinking that *SINCE* the front is so much heavier that I would *WANT* the tall springs (hence more potential energy) on the longer struts in the front...
I was just originally worried that by having the tall springs installed on the front that I was putting undue extra compression on them which would cause premature failure. HOWEVER, since the rear struts are SHORTER than the front, by placing these tall springs on the shorter struts, the constance compression would also be present (and I would have no tension and quite a large free gap on the front struts by installing the short springs). Of course the rear of the car is lighter, so the constant compression force would not be nearly as great as the front, but it was quite a lot of compression I had to use to get the tall springs installed on the front/long struts in the first place and by compressing them even more to get them on the rear/short struts might even be hazardous to my health!
Is this current configuration, with the tall springs on the long struts, a safety hazard in any way? I do not see how it could be, because of my stated facts above, but I am driving to Ontario this weekend for a family renunion and would hate to have to tow my car back to Ohio...
Someone please explain the flaw in my logic...
#8
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Originally Posted by zaphod
Oh, this does not make my day. The rear wheel-well gap looks right.
Originally Posted by zaphod
Today at 4 AM on my way driving the car to the airport I got to thinking again.
* The front struts are longer than the rear struts
* One pair of springs is taller than the other pair
Keeping this in mind, if the short springs had no tension (actually a decent gap) on the short struts, then the short springs would have even a LARGER gap on the long struts (front).
* The front struts are longer than the rear struts
* One pair of springs is taller than the other pair
Keeping this in mind, if the short springs had no tension (actually a decent gap) on the short struts, then the short springs would have even a LARGER gap on the long struts (front).
Originally Posted by zaphod
Now, I realize the front of the car is probably at least twice as heavy as the rear, so the shocks will never be fully extended, BUT, this still leaves me uneasy. In *MY* logic I'm thinking that *SINCE* the front is so much heavier that I would *WANT* the tall springs (hence more potential energy) on the longer struts in the front...
Last edited by MO REX; 06-29-2005 at 08:59 PM.
#9
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Join Date: Mar 2003
Location: Columbus, Ohio, United States
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Car Info: 2000 Impreza 2.5 RS Blue Ridge Pearl
Thanks for the reply! I'm virtually positive the front shocks should be higher than the rear shocks. But I will call TireRack and ask them since that's where I bought the struts and springs.
I say the car does look okay on the wheel-well gap, but since the stock springs were compressed nearly 2" already I'm not sure that I am qualified to say it looks right now. haha. The new "shorter" shocks/springs actually "raised" the car 1".
I get home from this business trip late tonight, and will take a good look at the car in the morning and see if the gap in the front is roughly equal to the gap in the rear. I'll post back with my results, as well as the info from TireRack.
thanks again!
Jacob
I say the car does look okay on the wheel-well gap, but since the stock springs were compressed nearly 2" already I'm not sure that I am qualified to say it looks right now. haha. The new "shorter" shocks/springs actually "raised" the car 1".
I get home from this business trip late tonight, and will take a good look at the car in the morning and see if the gap in the front is roughly equal to the gap in the rear. I'll post back with my results, as well as the info from TireRack.
thanks again!
Jacob
#12
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I’m no expert on the subject but AFAIK the motion ratio of an Impreza is 1:1 so I don’t think that would change anything but I just remembered that the Pro kit uses progressive rates and the ERS springs I was using are linear (different % front to rear from the 1st rate of the pro kit) so disregard the static rest figures I wrote (time to edit/erase) .
Pro kit progressive rates (not sure if these are accurate but it was all I could find)
Front - 1st Rate= 171 #/inch
2nd Rate= 193
Rear - 1st Rate= 94
2nd Rate= 161
BTW, if you have some info on the motion ratio of an Impreza that contradicts my #’s or how it will change static rest #’s please speak up.
Pro kit progressive rates (not sure if these are accurate but it was all I could find)
Front - 1st Rate= 171 #/inch
2nd Rate= 193
Rear - 1st Rate= 94
2nd Rate= 161
BTW, if you have some info on the motion ratio of an Impreza that contradicts my #’s or how it will change static rest #’s please speak up.
Last edited by MO REX; 06-29-2005 at 08:57 PM.
#13
I dont have any info, my car (which is actually an old legacy) is in a very lightly tuned and im satisfied with it.
1:1 really makes it easy to calculate rates though, that's cool.
Progressive springs suck. You don't know how the rate increases and matching struts to them never works out quite right.
1:1 really makes it easy to calculate rates though, that's cool.
Progressive springs suck. You don't know how the rate increases and matching struts to them never works out quite right.
#14
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Location: Columbus, Ohio, United States
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Car Info: 2000 Impreza 2.5 RS Blue Ridge Pearl
Okay so after arriving home from the airport I can definitely see that the front of my car is up ever-so-slightly higher than the rear. Furthermore, upon inspecting my stock struts (thankfully my wife did not throw them away while I was out of town), to my utmost surprise I found that the REAR struts were LONGER than the FRONT!
So now this totally makes sense in my head why the TALLER springs should be on the REAR... cuz the TALLER STRUT should be on the REAR!
I'm just happy that I won't have to remove the springs from the struts! All I need to do is swap the front and rear assemblies. W00t!
Thanks for all the info everyone. I'll post pics before & after soon so you can see the diff.
J
So now this totally makes sense in my head why the TALLER springs should be on the REAR... cuz the TALLER STRUT should be on the REAR!
I'm just happy that I won't have to remove the springs from the struts! All I need to do is swap the front and rear assemblies. W00t!
Thanks for all the info everyone. I'll post pics before & after soon so you can see the diff.
J
#15
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Car Info: 2000 Impreza 2.5 RS Blue Ridge Pearl
So after sleeping and probably dreaming about this all night, I now realize that if indeed the rear struts are longer than the front struts:
* Why do the rear struts (taller) have the 4-position damper adjustment on the top where I could only get to it by removing the back seat?
* And that would make the front struts (shorter) have the lower side-mounted 8-position damper adjustment.
It makes more sense that TireRack swapped the two struts. Seems to me I should have the top-adjustment type on the front (shorter) and the side-adjustment type on the rear (longer), but indeed they're swapped.
Upon inspection I notice that the longer strut has the welded flanges for the brake-line and the ABS sensor, whereas the shorter strut has only the flange for the brake-line. This flange configuration, along with the top-mounted dial v. the side-mounted dial, is what led me to believe the longer struts belong on the front.
I've placed a call to the sales rep at TireRack that fulfilled my order. Hopefully he'll be able to tell me that they sent me the wrong configuration... What do you think the chances are they'll let me return all four struts to be swapped with the proper configuration?
* Why do the rear struts (taller) have the 4-position damper adjustment on the top where I could only get to it by removing the back seat?
* And that would make the front struts (shorter) have the lower side-mounted 8-position damper adjustment.
It makes more sense that TireRack swapped the two struts. Seems to me I should have the top-adjustment type on the front (shorter) and the side-adjustment type on the rear (longer), but indeed they're swapped.
Upon inspection I notice that the longer strut has the welded flanges for the brake-line and the ABS sensor, whereas the shorter strut has only the flange for the brake-line. This flange configuration, along with the top-mounted dial v. the side-mounted dial, is what led me to believe the longer struts belong on the front.
I've placed a call to the sales rep at TireRack that fulfilled my order. Hopefully he'll be able to tell me that they sent me the wrong configuration... What do you think the chances are they'll let me return all four struts to be swapped with the proper configuration?