2004 Forester & trailer swaying [long]

Several people have had good luck towing a trailer with previous model Subaru Foresters. I do not know why mine is different. I just bought a 2004 Forester tried to tow with it. Mine is a nightmare. It is unstable above 40mph. It has a lot of side to side sway above 40mph if there is any steering input. It is almost harmonic in nature - it does not dampen out quickly. If feels like you are driving on Jello. It feels like the problem is much more the tires than the suspension. Though that is hard to prove.

Even when parked if you push on the hitch with your foot the Forester will sway side to side [right and left] a lot. You can watch the rim move right and left in and out of the tire. I think the sidewalls are just really weak. The tread is probably relatively soft also.

The Forester's tires are Yokohama Geolander G900 P215/60 R16 94H. Even in normal driving the steering response and cornering are poor. [Other Foresters may be equipped with 15" tires, and other models of Geolander tires - rather than the G900].

My Mazda MX-6 [much lower car] has Pirelli P4000 P205/55 R15 87H - it is stable, and if you push sideways it does not sway side to side anywhere near the degree that the Forester does. Steering response and cornering are good.

The Geolander G900 has a tall soft sidewall, it is 4.500" above the rim rather than 3.625" for the P4000 [24%higher].

My best idea right now is to change to a shorter and stiffer sidewall tire.

I am considering changing from P215/60 R16 94H

- an "H" rate tire with 60% width/height ratio, to Bridgestone Turanza LS-V 225/50R16 92V - this is a V rate tire so the sidewall is stiffer and at a 50 or 55 ratio it is shorter. This is the V rated version of the tire that some other Forester owners have [LS-H]. The tread should also be a harder sports car like compound.

Some of these tires are rated and discussed on

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It seems that Steering response and cornering stability are good expressions of my issue. On tirerack there are a mass of good comments on the Turanza tire - though I doubt anyone is towing. As far as I can tell everyone on "tirerack" hates the geolander 900 like on mine.

Does anyone else have any Experience changing to a shorter V rated tire for better stability?

My trailer does great and stable to 85+mph behind my Mazda MX-6, so I do not think it is the trailer. The trailer weighs ~1800lbs [816kg]. The tongue weight is 153lbs [69kg]. The Forester's manual says to keep the tongue weight between

8-11% of the trailer. 8%=144lbs [65kg] 11%=198lbs [90kg]. [the max allowed is 200lbs on the tongue] The manual transmission version of the Forester is rated for 2400lbs [1088kg] towing capacity.

I have already tried raising the tire pressure on the rear tires to

41psi [2.8bar] as recommended by the manual. The trailer tires are about 40psi.

------ Since my original write up I have learned the following: The dealer told me that the 2004 model is the first to be equipped with the Geolander G900 tires, previous years had a different model tire. This is the only change to the suspension that he is aware of between the 2003 and 2004 model.

The Maximum tire pressure on the tires is 44psi, so I upped the rear pressure to 44psi and the fronts to 41. [for towing the manual says

29psi front, 41psi rear]. I also changed the hitch from a straight one to a "drop hitch" it is now 1.5" lower than the straight one. The drop hitch is about 4.0" shorter than the "lift hitch" [bent receiver hitch] that I originally tried. The hitch ball is on a short receiver. A test drive showed that the lower hitch/ball placement and the higher tire pressures are an improvement. However still not acceptable. I think the higher pressure stiffened the tires but not enough and the tread is still too soft.

I have heard another Forester owner has had good luck with 75-100lbs of tongue weight. An additional test drive was done after I moved several items out of the front of the trailer to the back of the Forester. This reduced the tongue weight to 118lbs [down 35lbs from

153]. The swaying seemed worse with the lower tongue weight. [This follows the logic I have heard many times].

I would like to hear some other ideas, especially to know if others have switched to better performing tires.

Chris

Reply to
chris
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Trailer weight distribution is far more critical than one would think. I have a friend who rolled his F150 while hauling a 16ft cargo which was loaded waaaay wrong... going down a hill... started to sway.... bang... all over in a heartbeat. totaled the truck and turned the trailer into a ball of foil...

I try to have 10-15% of the total weight on the tongue as a general rule. But your tires may need to be replaced...

Reply to
D

Yes, your post was very long.. ;-)

My wife drives a 03 Forester. We have a 5X8 trailer that we use to pull my motorcycle and other things. The trailer is rated for

2000lbs. One day I got some mulch that weighed about ~600lbs. I noticed that the trailer was swaying on the highway on the way home. I then checked the tire (tyre for our nonUS friends) pressure and noticed it was a little low. So, I corrected it and also pumped up the tire pressue on the car (check sticker on driver door frame). This made a huge difference. Now everything is OK when driving.

Took the motorcycle (weighs about 430lbs)on vacation with me and drove about 800 miles. No a problem with the trailer.

So, my advise is to check tire pressure and increase it to the recommended towing pressure when you use the trailer. Also, only load your trailer to 1/2 the load rating. These little utility trailers are cheaply made and this load rating is (in my opinion) an absolute limit. Should solve the problem.

Reply to
Mark

I have a Forester MY01, and towed a 3300# trailer without any swaying at all. Even when being passed by the big rigs there was no swaying. The biggest thing here is 60% in front of the trailer axel and 40% behind the trailer axel. And a even balance left and right. Your tires may play part it this, but I don't believe to the same extend the loading of the trailer. Loading your trailer to minimize your tongue weight is probably what is causing the problem. If you have 60%/40% balance and you are over your max. tongue weight then lighten the trailer.

I once saw a guy towing a big power boat behind his Ford SUV Expedition, it was swaying every where he went. And I suspect most of his weight was on the tail end since that was where the motor located!!!

Etienne

Reply to
Etienne

True story. You need a significant portion of the total trailer weight on the trailer tongue (~10%). Hitch/ball height also plays a role; the trailer should ideally be pretty level, and slight;y lower in the nose is OK, but having the tongue end raised (hitch/ball too high) is asking for trouble.

ByeBye! S.

Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101

Reply to
S

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