[Hardrvin]

I've always wonder how much truth/validity there is to the saggy butt syndrome that everyone complains about. Is it really saggy butt because take-off setups drop the car incorrectly, or is it because the fenders just look that way from the get go.

Today's project involved taking my '05 FXT from stock struts with Forester specific pinks to '04 take off's w/ RCE Blacks.

Notes of interest. As noted in Porter's thread, the front struts in terms of knuckle to spring perch relationship are indeed the same. The rear Forester struts have ~0.5" more space between the knuckle mount and bottom of the spring perch. So with that said, the same given spring on both struts would result in 0.5" taller rider height in the rear. This does promote the theory that saggy butt does occur with STi/WRX take-off's.

I took some measurements using suspension mounting locations as "control points" versus the fender. Installed the '04 STi struts w/ the RCE blacks, jounced the suspension and remeasured. Hmmmm...

So the front dropped nearly another 2.25" whereas the rear only dropped about 1.5" End result is the car actually sits higher relative to the front than it did previously. Go figure.

Argue away. Very important note is that these are RCE Blacks so the spring rate is pretty high on them. I'm wonder if the front/rear weight split on an STi may result in the rear sitting down a hair more. Uncoming plans involve an R180 out back, so we'll see how that affects things.

 

[Hardrvin]

Forgot to note in the initial post; front lower arms were still below parallel however the rears went "inverted" thus my rear roll center in theory is fubar. Hopefully going STi rear subframe or at least WRX and hopefully that'll correct. I'll also try the removal of front spacers at that time too and should make things peachy up front as well.

 

[FXTRunner1]

Cool, Any pics? Hows it drive? On the saggy butt syndrome maybe that happens with sti springs as they might have a lower compressed height? By the way, what is the center hub to fender height?

 

[Hardrvin]

^ I've only got a lousy cell phone pic. I'll try to get some decent ones tomrrow and get those measurements. Also note that my measurements are taken as the car arrives from the dealer w/ some misc junk in the spare tire area. For auto'x I'll ditch the spare and that misc junk (cig lighter pump, a good gauge, a shackle (to go w/ the tow strap during the winter), a plug kit).

 

[The Black Box]

With the STI set up I never had sag in the back. It's the fender shape. Measure from axle to fender lip.

I don't think the rear is much of a concern as far as roll center is concerned. The camber curve issues are in the front.

 

[Hardrvin]

From the ground to the fender...

F: 25 3/8"
R: 25 1/4"

 

[Tuned200]

Looks about level to me. The front wheel opeing is larger than the rear, which causes the illusion that the back is lower. Just measure the distance from the fender to the ground f/b. with my 07wrx take offs, I was .25 inches lower in the rear. I never measured the stock for comparison.

Looks good!

 

[forfun]

Looks grate ,What size wheeels and tires are you running?

 

[imprezu]

Mine doesn't sag either.

 

[FXTSPORTS08]

This is STI springs/struts with 2" spacers both front and rear. The rear is 1/4" lower to fender lip but thats the way it was from the factory as well.

 

[stan_t]

Don't know about STi struts, but with WRX struts the OEM STi springs absolutely will give the car larger gap in the front than rear. But, that's how the stock STi looks also. RCE springs are different and you most likely won't have this problem with them.

Prodrive STi springs:

STi OEM springs:

Stan

 

[wadejg]

The "saggy butt" is just a kind of optical illusion, but it is also real. The relative drop of the STI setup is a bit more in the back than the front and it does make the butt look kinda saggy. The above pictures demonstrate it well.

Regards,
Justin Wade
2004 FXTi

 

[Hardrvin]

^ Optical illusion? I have hard measurements indicating that the front dropped more than the rear w/ an STi setup. It seems the the fenders were setup w/ more gap in the front than the rear from the factory.

As for my wheel setup, it's '04 STi wheels (17x7.5) w/ 225/45 Star Spec's.

 

[FXTSPORTS08]

^ I completely agree! There is no saggy butt! If you look at the factory specs the rear fender gap is 1/4" smaller then the front. Then when you go to STI suspension the difference stays the same or gets smaller! STI suspension is just about perfect for the SG!

 

[mtskibum16]

So the front dropped nearly another 2.25" whereas the rear only dropped about 1.5" End result is the car actually sits higher relative to the front than it did previously. Go figure.

I know this is old but I still have some comments. One reason the front drops more than the rear with aftermarket springs is that all aftermarket springs I've seen have dropped the front significantly more than the rear and this is do to the STi have a jacked up front (or saggy butt) look from the factory. The blacks are only listed as a slight difference in drop but I bet if you check some before/afters for STi's they're getting a bigger difference than spec'd. I know my prodrives on my STi were spec'd for lke a 1/4" front/rear drop. Well the front dropped over an inch iirc and the rear only dropped about 1/4".

I completely agree! There is no saggy butt! If you look at the factory specs the rear fender gap is 1/4" smaller then the front. Then when you go to STI suspension the difference stays the same or gets smaller! STI suspension is just about perfect for the SG!

There may not be an actual "saggy butt" from stock to STi takeoffs (I never measured stock) but bottom line is with STi takeoffs the rear has less gap than the front just like a stock STi and that's why ALL aftermarket springs drop the front more....to level it out. SO rather than drop the front on our already slammed STi t/o Foresters we can raise the rear to level it out.

So here's my situation: I currently have STi springs on stock struts an the F/R axle to fender measurements are exactly the same at 14 3/8" which I think is perfect. Now, I just got STi struts and per measurements and TiC the rear is going to drop 1/2" relative to the front going from stock to STi struts with the same springs. That will make the axle to fender measurement 1/2 LESS in the rear than the front. I don't care if that's how it is stock too, but that my friends is a SAGGY BUTT (or jacked front) just like the STi has stock.

Long story short I'm trying to decide if I should do 3/8 spacers (no new studs = slightly cheaper) or 1/2" spacers for the back. Thoughts? I'll post results when I do the swap.

Edit: There is this same never ending argument for 4Runners and again that's why pretty much all lifts or "leveling kits" raise the front 1" more than the rear. Since the fenders are shaped very different front to rear, people measure the heights based on the frame/running boards to see if the truck is sitting level rather than using only fender measurements.

It would be cool to get a stock suspension, STi takeoff, and STi takeoff with saggy butt spacers on scales and see how the weight distribution changes.

 

[xveganxcowboyx]

For what it's worth, I have STI take offs on my Forester and have had them on my WRX wagon with 3/8" spacers. The spacers made things level or even slightly raked on my wagon. The Forester setup without spacers has a very small amount of sag, but I do not think it looks out of place. My measurements showed 2" drop in the front and 2.25" in the rear. By those measurements 3/8" spacers would give a 1/8" greater height in the rear than the original ride height. (which accounts for the very slight rake I saw in my wagon).


I too would be curious about weight distribution. If anyone wants to loan me a set of corner scales I will swap between the three and measure them out.

 

[mtskibum16]

Just an update....

As I said before, my car with STi springs and stock struts was even front and rear with a measurement of 14 3/8" from center of the hub to the fender.

Well I just installed 04 STi struts that were freshly greased with grease fittings added F/R. The rear didn't drop as much as I had heard it would and the front actually raised a little. So new measurements with 04 STi struts and 05 STi springs: 14 1/2" front (raised 1/8") and 14 1/4 rear (lowered 1/8" inch). So 1/4" difference in height from front to back. The difference is noticeable, but probably not enough that I'll worry about adding a spacer. My plan was to install the struts, measure, then get a rear spacer to even it out but with only 1/4" difference I won't worry about it.

I will say that the car feels SO much better! The 04 struts with fresh grease are really plush compared to the stock struts and obviously control the STi springs better too. I'm very happy with the ride and the performance of the stock STi components. I had planned for this to be a short term mod until I got D-specs but at this point I'll be keeping it as is until the struts go. Up next STi steering rack, 22mm sways F/R, and remove the spacers to fix the geometry.

Edit: I drove the car around hitting every hole I could and swerving back and forth to settle the suspension before taking measurements. I'll measure again after a few hundred miles.