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Old 01-23-2013, 05:19 PM   #591 (permalink)
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I will share my perspective on air pressure and my methods/formula. I drive a lot of vehicles and manage a large fleet so I create short cuts for myself that have proven themselves over many years. This is my goto method and then I may vary slightly from there.
To Start: I take the Vehicle recommended tire pressure as the minimum (comfort oriented and much less will trigger TPMS) so for my OB is 32f/30r. This also tells of the weight distribution of the vehicle, we are nose heavy, in fact i find 3psi variance front to back is closer. but here goes how I do it using stock tires as an example.

Oem tires rated load index 98T = 1653lbs @ 44psi (Tire max pressure)

Vehicle curb weight 3500lbs (rounded out for this example)
3500/4 = 875lbs per tire = 53% of tire load rating.

Max tire pressure (44) - Subaru recommended pressure 32/30 (take highest on door jam) =
12psi range so

12x53% = 6psi (rounded)

Result
Front = 32+6 = 38psi
Rear = 30+6 = 36psi.

always seams to work out you can tweak from there. My new tires are Load index 99H so my numbers come a little less PSI due to higher weight capacity and right now I am at 37/34, and like it

To follow this concept, my trucks for example that have mounted equipment and are closer to there max weight full time I would calculate on their scale weight and would end up closer to max air pressure.

For Passenger vehicles curb weight is good, then just watch tire wear comfort etc. because different tires may need a slight tweak up or down from this but generally within 1 psi.

Hope that made sense and it is just my own quick and dirty method that I have to use regularly.
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Old 01-23-2013, 05:54 PM   #592 (permalink)
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Should mention also, with my personal vehicle, I will drive a new one for a while close to manufacturer spec so I have a feel for the changes when I apply preferred air pressure methodology.
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Old 01-23-2013, 06:25 PM   #593 (permalink)
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glad to see folks looking for the source of the problem rather than trying tweaks - I think there is a good deal of knowledge and insight among drivers who love these cars -
I like SeanU's theory approaches. If we have theories we can test them and derive engineering answers. There is a subjective component however that defies engineering. Operating any sophisticated piece of equipment ordinarily requires a learning period where you test your operating skills and abilities against the equipment's performance capabilities. Then you develop new skills to operate the equipment at its optimum performance level.
I think those of us who drive the Gen 4 frequently develop a skill set adapted to the Gen 4's peculiarities. I think the Gen 4 handling peculiarities demand a greater degree of driver concentration, with resulting driver fatigue, than FWD and RWD vehicles of this class. I never experienced this out of control situation with the Gen 3s.
Out of self doubt, I have loaned my Gen 4 to various family members, without mentioning any handling peculiarities. Afterwards, almost all of them have asked me whether I like my Subaru. I respond by asking why do you ask? The response: I felt a little out of control on the highway, but around town it was great.
I conclude that while it is possible to placebo effect improved performance (tweaking tires, alignment, anti sway, etc.) that in final analysis we are all simply reducing our expectations of long distance cruising comfort with the Gen 4. That is sad.
I shouldn't have to fight with my car to stay in lane. Does anyone but offroaders think the Gen 4 handles better on the highway than the Gen 3? Why is that?
I truly believe the marketing guys arm twisted the engineers to alter the design to compete with the "me to" lifted competition. Subaru engineers are too good to have made this design error. The marketing folks are what destroyed Detroit engineering in the 70's. I don't like seeing that being repeated at Subie. I don't think Subie owners care whether they look like Toyota RAV4 or Honda CRV.

Serious offroading requires drastic alterations that look silly on the highway and are unsafe at speed. I bought my 2012 Subie while totally ignorant of this wander issue.

We should not quietly take the marketers side in changing performance characteristics to "look like" the competition. The engineers are constantly being asked to cheapen the vehicle to improve profits. I thought Subie took the higher road. This entire thread shows me I was wrong.
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Old 01-23-2013, 06:50 PM   #594 (permalink)
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All the theories aside, the only thing we know fore sure is that the 4th gen cars seem more sensitive to toe settings than previous generations (unless somebody can point to a similar thread for the older cars).

Aerodynamics could play a role - a taller, lighter car is almost certainly less stable at high speeds than a lower, heavier car. The only question here is "how fast before I notice?" My experience is that at speeds normal in most roads that have speed limits (say, under 75 mph), I do not see a degradation in stability. Is the OB a bahn-burner? Of course not. That's not what it is designed for. And while it would be interesting to try a front chin spoiler, it would be so far off the ground that it would likely not be effective. Either that or it would seriously compromise ground clearance. So I don't see us being able to affect this substantially, short of lowering the cat (but if somebody wants to try - go for it!).

I would not be surprised to learn that there is a bushing or two somewhere deep inside the front and/or rear suspensions that affect dynamic toe change while the car is in motion, that are a little too soft and thus allowing toe to change too much while driving. But that's just a guess and hard to validate.

So what can we do?

In the end I implore everyone who has an issue to start with a dealer, make your displeasure known, and then, if you have to, go to a private alignment shop and pester them until you are happy. Most have a 30 day guarantee that should work to your advantage.

And yes, pester Subaru to see how they respond. I still think a poll like the following is in order:

- My 4th gen does not have stability issues.
- My 4th gen had stability issues, but the dealer fixed it.
- My 4th gen had stability issues, but I had to go to a private alignment shop to fix it.
- My 4th gen has stability issues, and no alignment has fixed it.
- My 4th gen has stability issues, but I have not tried to fix it yet.
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Old 01-23-2013, 06:55 PM   #595 (permalink)
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Quote:
Originally Posted by 350Z-not View Post
I conclude that while it is possible to placebo effect improved performance (tweaking tires, alignment, anti sway, etc.) that in final analysis we are all simply reducing our expectations of long distance cruising comfort with the Gen 4.
With all due respect, this is complete B.S. Alignment has a very real affect on stability, on the OB and on all cars. It may not fix it to everyone's content, but to say I and others are imagining things is simply insulting.

BTW, have you had you car properly aligned?
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Old 01-23-2013, 07:06 PM   #596 (permalink)
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Compared to the Gen4 Legacy the OB drives like a clod. Switching to a better built tire has sharpened up the handling just a smidge with all stock suspension. Alignment 100% can impact handling not only that but alignment efforts is not an exact science a good shop will tell you that they might need to see the car multiple times to get the alignment / handling sorted out to your liking.

A shop that simply does alignments will simply charge you each time the car gets racked and go through the motions to a pre set list of numbers given to them via the auto maker specs.

Even when I test drove and rented an OB in 2001 when I was considering the idea I found them to be floaty with horrible handling which is why I bought a Legacy GT instead. Night and day difference. Fast forward to the Gen4 and nothing has changed the Gen4 Legacy which we have one in the family I get to drive occasionally is dramatically better than the Gen4 Ob I spent much of my time in hauling kids around.

As they all say Money will fix anything if you have enough of it.
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Old 01-23-2013, 08:08 PM   #597 (permalink)
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Right - a sports sedan/wagon will absolutely handle better on the street than an OB. That's not what I was getting at. I was specifically talking about straight line stability, but you are correct that the Legacy's tires could affect that as well.
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Old 01-24-2013, 07:52 PM   #598 (permalink)
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Quote:
Originally Posted by Georgeh View Post
I still think a poll like the following is in order:

- My 4th gen does not have stability issues.
- My 4th gen had stability issues, but the dealer fixed it with an alignment.
My 4th gen had stability issues, but an alignment, and better rsb, or other modifications fixed it.
- My 4th gen had stability issues, but I had to go to a private alignment shop to fix it.
- My 4th gen has stability issues, and no alignment has fixed it.
- My 4th gen has stability issues, but I have not tried to fix it yet.
Sounds great, go for it. I added a choice in the middle and altered one, but. Not totally convinced its right yet. Might want to give a choice of toe angles that fixed it. Also, could the poll be added to this thread for consistency, not allow this discussion to blow up all over the forum?
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Old 01-24-2013, 08:22 PM   #599 (permalink)
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Thanks for suggesting some changes.

Not sure about adding the poll to this thread - it's a good idea. Mods?

If not we can reference this thread in the first message of the poll.

Any other ideas out there for changes to the poll? I'd like this to be "crowd sourced."
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Old 01-24-2013, 08:54 PM   #600 (permalink)
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I don't think adding a poll to this thread would help. Referencing as mentioned would be the best plan.
We should start a new poll with a title like "Do You Have Stability Issues Gen IV OB: Vote Below"
and use the 5 of so choices provided. With maybe a kicker at the bottom with a yes or no choice. "Would you buy this OB again knowing what you know now?"
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