Rear Wheels Leaning In?

Here's a picture down the same side of the car to compare the rear lean in angle with the front.

Michael

Wow, that is a fabulous looking machine.
(Sorry this isn't actually helpful! )

I have seen billet aluminum fully adjustable arms. I belive there is a section @ panteraplace.com where somone shows how he fitted them. The venders have them adjustable. I keep thinking Pro Proformance. If someone else dosent jump in, I will do a search for you.

Thanks Derek!

lpb,

Thanks. I've heard of adjustable control arms too, but I wonder if there's another solution, rather than replace my control arms again.

Does anyone know if offset bushings would do the trick, and if they're available?

Does anyone think the rear wheels look like they're leaning in?

Michael

They look plumb to me, but the tire wear will tell all. Probobly what happens is under hard acceleration, she squats a little, and wears inside, you should drive hard on some winding roads to even out the wear. Just kidding! I'm still giggiling from the detective work on the fuel pump!

I bet almost anything it is from rubbing the fenderwells when you hit bumps in the road. You have your spacers on your shocks removed by any chance?

Michael -
It doesn't help you any, but my rear tires do the same.

I brought it to an alignment shop to correct it, and they told me that they had already dialed out all the camber they could. The way to solve this problems is with the aftermarket a-arms, which you apparently already have?

As a short term solution, I rotated my tires so that they would wear the "other half" a little more.

I guess what I'm saying is that the late model wide-body cars may come like that from the factory? Can you dial it out with your aftermarket a-arms?

One other thing that comes to mind - PLEASE PLEASE look at the attachment point of the a-arms to the chassis. My upper a-arm literally pulled through the chassis (photos available upon request) and it would have been really ugly had that not happened while my car was being dragged onto a flatbed. (my guardian angel really does a decent job sometimes). If you cannot get the camber you want despite aftermarket a-arms, perhaps it is because your upper a-arms are starting to pull through the chassis?

DeTom,

I really don't think they're rubbing anywhere. I paid special attention to that after installing the wheels. I even took the wheels off after some mileage to make certain the tires weren't contacting anything (and they weren't). I will take another look, though, just because anything is possible.

The first picture of the tire was taken in my driveway after driving about 20-25 mph through my neighborhood on the way home. The tire should've been rolling flat.

Could it be the car and tires are so wide that the edges of the tires are actually hanging off the crown of the road? It seems like a stretch, but I'm examining all possibilities at this point.

Michael

Charlie,

I saw some pictures years ago of a white 5-S with the right rear inner tire so prematurely worn, that the belts were hanging out! The tread on the other side of the tire looked good. It was on a flatbed.

There were also pictures of the lower control arm on that side that had pulled the bolts through the frame rail. It did not look pretty. Was that your car?

In any event, thank God that didn't happen to you on the road!

At some time in it's life, my 5-S had a modification performed on it that addressed this problem before it happened. Plates were welded along the inside of the frame rails where the control arms bolt through to strengthen these areas. I will inspect those areas just to make sure they aren't failing.

Thanks for the suggestion, Charlie.

Michael

Well the reason I said that is the pattern is the same on mine, only mine are a lot worse. It only happens when the upper limits of suspension travel are reached. I have since, just this past weekend, corrected mine. All I had to do was re-install the crossmember bar correctly and they stopped rubbing. I even posted about it because I was tickeled pink by it.

DeTom,

Yes, I remember the post. Something so simple correcting something major is always great to read about!

Any and all suggestions are appreciated, thank you. I'm going to take the wheels off and examine the wheel wells for rubbing, the control arms to see if they actually are extended, and the frame for pulling. I don't expect to see anything wrong.

I don't remember seeing this with my 15"s. I wonder if the increased diameter of my new rear tires amplifies the original deficiency? We may be in new territiory here!

Charlie,

Did you notice a change in handling or control prior to the control arm looking for a solo vacation? Or did it just happen all at once? If you can find the time, I'd like to hear the story of your control arm woe.

Michael

Michael & all,

Recipe for George's handy home camber gage:

You need a length of 1/4", 3/8" or 1/2" steel square stock, cut to length so that it fits from bead to bead on your wheels without hitting the sidewall of the tires or the extreme rolled edge of the wheels (a little over 19" in Michael's case). Now acquire a large calibrated angle/protractor bubble level with a magnetic base. The good ones are calibrated to +/- 0.5 degrees. The larger the scale, the easier to read differences in angle.

Hold the steel stock vertically from bead to bead across your wheel & attach the level, you can get a fairly accurate reading of camber. Much more accurate than your eye, and more convenient than driving to the alignment shop every time you want to monitor your camber setting.

There are also decent home / track side alignment tools sold by several companines in the $600 to $1K range.

This problem is why there are adjustable camber bars & adjustable upper rear control arms sold for the Pantera. The additional force applied to the chassis by wider tires accelerates the problem, and the wider spacing of the rear tires on the GT4 / GT5 / GT5-S increases the force even more. It doesn't take much "flex" or "give" in the chassis to throw the camber off & the wider the tire OR stiffer the sidewall, the more sensitive the setting is.

I am a new Pantera owner, but I'd bet a round of drinks that the chassis flexing at the upper rear control arm could be reduced if the mounting of the camber bar were spread out, attached at 3 points on both sides rather than just one.

your "1/2 a bubble off plumb" friend on the PIBB, George

Mike,

From my experience it appears the uppers are too short in theory. when the car squats under acceleration the lower becomes level or longer. This creates a situation where the inner tire as of now has more contact and under acceleration as the lower increases in lenght the inner contact increases and out tire contact decreases. You have to create a compensation for the problem. Remember this is my first Pantera, but have played with the geometry of supsension a lot. I'm not familiar with your exact supsension, but it appears my car has shims on the lowers. I have not looked closely at the uppers. It would seem correct that they need to be shimmed out in your case ? This is just my 2 cents.

You guys are on the right track. Few realize that the removable cross member bar in the engine bay helps locate the upper a-arms. To get your rear suspension geomotry right you have to install it with no load on the rear wheels. Do not pre-load the member, but have all the weight off the wheels and then install it. And really crank down hard on the bolts because it will be under load once you lower the car back down. When I did this I gained almost a quarter inch of extra space inside the sidewalls of the engine bay. It is a miracle I tell you!! Imagine just doing something so small making such a huge differance in how the car feels. All you have to do is read this board and the email letter and you pick up on all sorts of cool stuff.

So how does this impact the alignment of the rear deck lid ??? Seems that the rear is very flexible if this is the case.

I'm not having any handling, suspension, alignment, or body flexing issues. The car handles very well, and is steady and predictable. The tires aren't even wearing unevenly, and I've got a few thousand miles on them already. I just don't want to ruin a brand new set of tires if there is a camber issue.

The ideas and suggestions are great, though, so keep 'em coming!

Michael

quote:

Originally posted by Cyboman:
Charlie,

I saw some pictures years ago of a white 5-S with the right rear inner tire so prematurely worn, that the belts were hanging out! The tread on the other side of the tire looked good. It was on a flatbed.

There were also pictures of the lower control arm on that side that had pulled the bolts through the frame rail. It did not look pretty. Was that your car?

In any event, thank God that didn't happen to you on the road!

At some time in it's life, my 5-S had a modification performed on it that addressed this problem before it happened. Plates were welded along the inside of the frame rails where the control arms bolt through to strengthen these areas. I will inspect those areas just to make sure they aren't failing.

Thanks for the suggestion, Charlie.

Michael

Yes, both of those were my car. It's a very long story, but I have a rather extensive collection of photos of my car on a flatbed tht I accumulated during the first year or two of my ownership. Knocking on wood, I think that is all behind me now...

quote:

Originally posted by Cyboman:
Charlie,

Did you notice a change in handling or control prior to the control arm looking for a solo vacation? Or did it just happen all at once? If you can find the time, I'd like to hear the story of your control arm woe.

Michael

No, I noticed no change in handling. Although to be honest, I was possibly so concerned about my engine falling apart that I wasn't concentrating on the suspension. I was on my way home from an International DeTomaso meeting in Italy, so I had been "highway droning" on a long and straight highway for several hours.

Ironically, I was probably saved by the fact that my engine did eventually eat itself, so I pulled over and called a flatbed. At some point between loading and unloading the car, the rear wheel fell off. Well, the upper a-arm pulled through the chassis. I'd spent much of the prior week driving through the Italian Alps at highly anti-social speeds, including an organized hillclimb event. Had that wheel come off a day or two earlier.... But I suspect that the stress of doing so was the straw that broke the camels back on my suspension.

Charlie,

It was the upper A-arm that pulled out? I thought it was the lower A-arm.

Michael