OK, do I need heavy duty rear springs?

Ratbag

Ratbag

Administrator
Joined
Jan 1, 2012
Messages
7,474
Location
Bayside, Melbourne, Vic
Car Year
MY06, MY10
Car Model
Forester SG & SH
Transmission
5MT/DR & 4EAT Sports
Gidday Folks

After towing the trailer around the back blocks of the Dandenongs today, I can see that I really need heavier duty springs in the rear.

E-30_JAK_2014-_4282419_Ew.jpg


Note that after taking this photo, I discovered that the rear P/S tyre was flat ... :(
Sidewall is busted badly.

Only about 6,000 kms on the set, so I am not very happy!

Anyway, back to the springs.

Being an XS, it has the SLS at the rear.

The tow ball weight was around 80 Kgs. This should reduce to about 65 Kgs when the trailer is correctly packed with its normal load.

I do not want any lift when not towing the trailer, but do want to preserve the normal angle of the car front to rear when towing and when not towing. Basically, this seems to say to me that I need stronger springs of the same length. Or is this not the only way to look at the problem.

BTW, the crazy F:R angle didn't seem to impact the steering or handling in any way, but I suspect that the headlights were possum hunting ... :iconwink:.

The tool box had 2x 10L Jerry cans, 3x gas bottles and some other stuff in it.
Winch and recovery gear at the rear of the trailer.
Both 20L water and fuel Jerry cans were full.

Suggestions?

Or just take it to Pedders and see what they say?
 
SLS aside ( question for the suspension shop i think) Your probably looking for std height springs with a higher load capacity, which (someone correct me if im wrong) should have a thicker coil. That will make the ride harsher but should only raise the height a touch over stock.

Raised kings ime are

  • harsh riding and make for crap handling (which i know is contrary to popular opinion).
  • They also aren't extra load rating from my experience towing the caravan, height's about the same with them from without them in the back.
  • They also leave the shocks topped out if you don't install long travel shocks, which the oem and kyb replacements are not.

Talking to an experienced pedders dealer would be the best place to start. Find out if their heavy duty springs mean extra load capacity, not just sales language used to put rosey tinted glasses over your eyes. If you do have to replace the shocks remember to check if they include new bumpstops, towing with worn out bump stops on the pistons will ruin the shocks quickly.

First off like you said pack the trailer properly and see how it rides, all that weight and box on the draw bar put the majority of the load on the car and little on the trailers axle. Which puts the weight behind the rear axle of the subaru, lifts the front and accentuates the matter. I usually tow a box trailer with a cage half full up the cage of fire wood with little rear end sag. Pulling the weight of the trailers another matter but it's only a few km from my parents block to my place luckily.
 
That doesn't look quite right to me.
I would've thought the SLS would have leveled the rear a little better than that, even with the trailers weight.

I'm going to go a bit left field & ask;
Are you sure they are SLS ? Could they have possibly changed out by the previous owner ?
And are they working, perhaps the SLS part has given up the ghost so to speak :shrug:

Sorry for all the Q's but I'm just thinking out loud :cool:

Ratbag said:
Or just take it to Pedders and see what they say?
Click to expand...
Be careful about Pedders, I've many many a bad story from those guys:catfight:

Regards
Mr Turbo
 
I'm with Mr.T, the SLS should handle the load you had on the towball.

Suspension doesnt last forever, perhaps you need new rear shocks &/or springs. Kings standard height springs are a little heavier duty than stock.

You could use Pedders as a starting point to find out if anything is wrong. I cant see them being successful with their sales speak with you lol :lol:
 
idw said:
SLS aside ( question for the suspension shop i think) Your probably looking for std height springs with a higher load capacity, which (someone correct me if im wrong) should have a thicker coil. That will make the ride harsher but should only raise the height a touch over stock.

Raised kings ime are

  • harsh riding and make for crap handling (which i know is contrary to popular opinion).
  • They also aren't extra load rating from my experience towing the caravan, height's about the same with them from without them in the back.
  • They also leave the shocks topped out if you don't install long travel shocks, which the oem and kyb replacements are not.
Click to expand...

I agree. I have raised king springs and new shocks and was severely disappointed to see the donkey still sags. And.prior to that the sls did jack.
I asked my dealer about heavy duty and they said that was the best they do. Hopefully its a different story for your foz.
 
Last edited by a moderator:
Haha thus my Dobinson springs are perfect. Saggs about 20mm when I have a 2tonne car/trailer on the back and a boot full of crap.
However they have a firm but not harsh (my opinion) ride but do not come in the standard height unfortunately.
My Foz is a limited and had the SLS and at 135, 000km gave out and sagged down by about 3". Personalky I'd replace the rear springs with some Kings or Pedders and change to a set od KYB rear shocks. I'm not a fan of pedders shocks and they are over peiced. You can get the KYB's for around $180 a corner, retail.
 
RB I suspect your SLS is in the process of dying under heavy load. It is far more cost effective to put in KYB struts and Kings. If I see you tomorrow night you are more than welcome to take my 2002 Foz around the block to test the alternative. My 2004 still has the standard SLS which works perfectly but I much rather the KYB and Kings set up.
I can also have a look and see if they are SLS struts just incase they have been changed.
 
Last edited:
Thanks for all the thoughts/suggestions, everyone.

HC, will see you tomorrow night. Thanks for the offer.

I have been reading up on threads about this before starting my own investigation.

The trailer is (almost) balanced. Needs around 5 Kgs load off the ball to comply with the OM. I expect to remove another 10-15 Kgs off the ball load when all is properly configured. I don't think this will help enough.

The SLS appears to be working with just the car loaded. It is supposed to compensate for trailer loading. The SLS struts are still there.

For some reason, the Forester seems to be more affected by having the trailer on than Roo1 ever was. Odd, that :confused: :shrug:.

Maybe my first stop should be at Ross' place?

Or maybe I need to have a closer look at what Tannin did to his?
His end results are here:
https://offroadsubarus.com/showpost.php?p=69208&postcount=88

His requirements seem to be very similar to mine.
 
Hi Ratbag,

My understanding is the SLS will adjust to the pre-set height as the suspension bounces up/down. Kinda jacks it up or down searching that height as the vehicle rides along.

Have ou driven a few kilometres to see if anything changes in the riding height?

Pedro.
 
Gidday Pedro

pezimm said:
Hi Ratbag,

My understanding is the SLS will adjust to the pre-set height as the suspension bounces up/down. Kinda jacks it up or down searching that height as the vehicle rides along.

Have you driven a few kilometres to see if anything changes in the riding height?

Pedro.
Click to expand...

Thanks for the suggestion.
Well, we had done about 170 kms before I took the photo I originally posted ... I reckon it was as pumped up as it was likely to get - not very :(. Maybe my SLS are stuffed. That could be the case, as the vehicle was previously used for open road towing by the previous owner.

Maybe moving the spare carrier to the rear gate might help. That starts to get as expensive getting new springs, or whatever though.

After reading Tony's post, I think I will give Lucas Automotive a call tomorrow.
 
pezimm said:
Have ou driven a few kilometres to see if anything changes in the riding height?
Click to expand...

Just saw your quick report on your drive... So looks like there was enough chance for the struts to adjust...

Did your rear end bump up higher than usual when you un-hitched the trailer?

Ratbag said:
Seems that Lucas Automotive at 9553-3995 might be a good place to start tomorrow morning ... AND they are local for me ... :).
Click to expand...

Lucas is a very nice fella. He does the heavy-duty servicing on my car.
 
pezimm said:
Just saw your quick report on your drive... So looks like there was enough chance for the struts to adjust...
Click to expand...

Yeah, and they didn't ... :(.
Saggier at the end than at the beginning, if anything.

Did your rear end bump up higher than usual when you un-hitched the trailer?
Click to expand...

No, it didn't :(. Not a good sign, IMO.

Lucas is a very nice fella. He does the heavy-duty servicing on my car.
Click to expand...

I am extremely happy with Ross for all our normal servicing and repairs, but suspension fine tuning is not his business.

It became apparent to me today that I am going to have to do whatever needs to be done before setting off on a 4,000 - 5,000 km trip with trailer coming back via western NSW.

Thanks for a second recommendation of Lucas. It seems that everything is in his favour; and he's local for me; and he's unlikely to rooster it up.
 
I reckon your rear self levellers are stuffed Ratbag. My 07 XT had them to 250,000km and in all the towing I've done they've never looked like that, even straight after hitching up the trailer before driving off.

I tow a Stockman Podtrailer camper which weighs 450kg fully loaded with 60L water and 2 x 20L petrol containers, spare wheel (under rear of trailer) and front box. It puts 47kg on the hitch according to SWMBO's bathroom scales (and her complaint is that they must read too high lol) which is around the 10% that seems to be a recommended weight. It tows flat like that even with stuff like 2 spare tyres, esky and odds & ends in the back. In fact with the power of the XT and the excellent balance and well chosen spring rates of the trailer I often forget there is anything behind. But the car still sits level at all times.

I recently replaced all springs and struts with 30mm lift King springs all round as seen on their website and KYB struts. The springs cost $153 each and the struts $177 each (all plus GST) the alignment was $80. The front springs are KSFR-32SP and the rears KSRR-43. The more I drive it the more I like it and it's a real improvement over stock. The ride is a bit firmer (especially initially) but actually better overall in spite of what some might say and what might be expected, and especially with a load. It is more level and controlled and is just wonderful over rubbish surfaces. Handling & steering and general feel is a lot better too. And there is a bonus of extra clearance - it's win,win,win all round. I wish I had this set-up on my trips to Birdsville, Camerons Corner and especially across the Gibb River Road.

We took the trailer out over the week-end and the new suspension coped magnificently - still level and so well controlled. The $1600 I spent has given me a better than new set-up for the rest of the life of the car. It's a really satisfying feeling to get the result that I did.
 
If you want to leave / replace your suspension as normal, e.g. SLS and it still does not do the job, perhaps consider a weight distribution hitch. That would leave your ride unaffected when not towing. (Would need to disconnect if offroad).
 
^ & ^^. Thanks Kevin & All.

Power's off here.

Pedders $674 for new rear shocks, variable rate springs, bumps, tops, assembled, as a kit. Alignment $132 :eek:. Fitting $250 :puke:.

Lucas will fit for $100-200. Alignment $66 ...

Guess who I'll get to fit & align ...:iconwink:
$840-940 all up.

Not quite as horrible as I thought it might be.

From my Batphone
 
Ratbag - am having same issue with my 2011 Forester X (which I believe does not have self-levelling suspension). If we load it up for camping (perhaps 400kg of luggage in back and on roof cage) the rear suspension almost bottoms out. Car is very nose-high and steering scarily light. Just bought a trailer and had a good trip camping with that - car handles better, attitude improved, but despite much reduced car load, and tow-ball weight around 45kgs, the rear springs are really bottomed out, car comes up hard on the stops on every bump. Also, towbar is now the lowest point of the car, and much scraping of bottom of tow-ball on drainage humps when offroading.

So, like you, I'd like to get stiffer springs all round, as well as getting as much lift as possible, via longer shocks?

Spoke to Wholesale Suspension in Sydney (King Springs wholesalers) but they weren't helpful in terms of advice - put me on to local suspension shop Heasman in Tempe (Sydney) who are researching and will quote me on replacing springs / shocks - but they didn't seem to know a lot about this car, more used to performance mods for onroad applications.

I'll let you know what they come back with, for interest.

Cheers

TG
 
Gidday TG

I just measured my wheel arch height to centre of hub.

Spec is F = 437 mm; R = 440 mm.

Mine is F = 434 mm; R = 400 mm - and that's just sitting at the curb, without even a spare wheel in the boot!

So I suspect that my rear suspension is, like a good tree, well and truly rooted ...

Seems that the Pedders variable rate spring kit is the way for me to go. Bolt off/bolt on. Off the shelf part. No assembly/disassembly of struts, springs, etc. Come complete with new bumps and all that stuff, including strut tops.

I am going up there this arvo to check them out, and will purchase if suitable. I cannot see why they won't be, but will keep you all posted.

While $674 for the pair (unfitted, w/o wheel alignment) is not exactly cheap, in my books, but not as bad as I was imagining it would be.

I also have a profound aversion to turning vehicles into a 'one of a kind' special. I did all that when I was much younger. These days, I just want a bog standard car that works properly for my intended purposes.

I have no plans whatsoever to touch the front suspension. It appears to be perfectly good. If it fails in the future, I will replace it with the standard parts.

My car is high enough for my uses (i.e. I don't need or want to lift it). However, I don't want to be dragging my rrrs or the trailer hitch along the ground either.

BTW, it is also my understanding that the X series do not have SLS. I also don't care if mine has it (it has ATM), or not. I just want the car to be stable, reliable and reasonably level under all conditions.
 
Have much the same inclinations as you, Ratbag. Would really rather get a pajero for this use, but a good 2nd hand one with <100,000km would involve tipping in $7-8k over the likely resale of my Forester, so will go with spending $1500 or so on getting a bit more ride height and heavier-duty suspension. Car only has 40,000kms on it, so hope to get 3-4 more years from it, and this upgrade should be good value for that time.
 
You must log in or register to reply here.
Back
Top