Rear wheels uneven at fenders
 

As I have been contemplating new wider wheels and tires, I noticed that the rear wheels/tires sit differently with realtion to the fender directly above. Putting a straight edge vertically across the faces of the tire sidewall (upper and lower), and butting that staight edge to the underside of the fender, this is what I get:

Driver side: inset from fender 7/8", and straight edge is nearly plumb

Pass Side: inset from fender 1 5/16" and straight edge is in-board (toward center of car) at the top of the tire about 1/2".

Knowing this, and standing about 30 ft behind the car, I can see the lean on the pass side (barely), and the difference at the fenders kinda bugs me. I've looked at this at different times, parked in various lots, but it always seems the same. Drove 50 miles today, reparked it in the very same spot in the garage and checked it. Identical measurements.

What's up ?? Is this normal?

I'm looking at wheels/tires that would move the tire sidewall out, and the closer they get to the fender, the more obvious this will be.

It's not IRS, how can the wheels be at different angles when parked on the same flat surface??

:screwy::screwy::screwy:

Take a look at your 2010 + . How does it sit.

Have you changed the springs or suspension in the rear of your car in any way from stock?


I ask this because lowering or raising the car will move the position of the wheels laterally in relation to the fender or body because of the fixed length of the panhard bar.

You're talking about two distinct things, rear wheel centering left/right, and wheel angle.

Since this is a solid axle car, and perceived angles are likely the body lines playing tricks on you, but the panhard bar is a fixedtype from the factory, and they likely have a tolerance fit.

To fix the left/right issue, look up adjustable panhard bars.

Adjustable pan hard will fix it. Wider tires exaggerates the condition even more

The car is bone stock with 1350 miles.

I was hoping that it WAS perceived, but when I put a straight edge across the sidewalls up to the fender, it became fact. A level on the straightedge tells me the wheel angles are different, as previously mentioned.

Thanks for the reply.

How did you measure the car on an even surface? I don't mean even with a carpenter's level but more so with a "machinist" level. I fail to comprehend how factory stock suspension is off this bad without some other mind of variable aside from an alignment and needing a replacement pan-hard bar to align the rear-end with the front once again.

So basically the car "leans" to the pass side and because of that lean the wheels appears to not be equal in left to right orientation. I don't think it's a panhard type of situation as much as it appears you have either a bad or weak spring or bent, broke,or damaged suspension component.

This is how I measured it:
I made a straight edge from 1/4" x 2 1/2" birch plywood, the height from the floor to the underside of the rear fender, short about 3/8" in height.

I placed that straight edge against both the sidewalls of the rear tire and slid the straightline up to contact the underside of the fender.

With a pencil I marked the position of the fender on the end of the straight edge.

Then, measured the distance from the sidewall contact edge of the straight edge to the mark. 7/8" for the d/s and 1-5/16" for the p/s.

The tilt was measured with a 24" carpenter's level placed against the straight edge. I leaned the straight edge out until plumb was reached, and measured the distance from the sidewall to the straightedge.

Also, the distance from the floor to the fender edge is 30-1/8" on the d/s and 30" on the p/s.

The car is parked in the same spot on a concrete garage floor. I also checked the measurements on my concrete driveway which is essentially flat.

Thanks for the help !

This is normal! It is due to the panhard bar which moves the axle from side-to-side. On a level surface the axle is supposed to be slightly off-center to the left. See this link for an animation: http://www.miracerros.com/mustang/t_suspension.htm

Also, if you're wondering, I factory ordered this car and took delivery with 5 miles on the odo.

A solid axle car with wheels at a different pitch? I looked under there and all looks clean and new, no bashes, leaks, etc. Car rolls smooth, no wabbles, etc.

Very interesting info link. Thak you. You say "on a level surface" the off center condition is normal. Please explain.

And, what about the pitch of the p/s wheel? If the p/s tilt of the wheel was near plumb (as is the d/s), then the uneven distance to the fenders would bascially be corrected. So, it would seem this is more of a wheel tilt (pitch?) problem...?

If the tire bulge at the bottom of the tire sits a bit different due to pressure or load, the angle of the bar used to set the level against will be changed. You might also measure the distance from the axle housing to the ground at the outer most points you can from under the car.

In order to find where the difference is, you must start measuring at the lowest possible structure. Also, front springs/tires/load can and will effect how the rear of a car sits.

Plus.....as mentioned I believe, the floor must be level also. Appearing flat and measuring level are two different things. Not saying you are not right, it is just after rebuilding several classic cars, these are some typical issues that arise and must be dealt with in truely leveling a car.

On a level surface and at rest the axle is at or near the furthest point to the left. As the axle moves up or down from that point the wheels and axle move toward the right. The motion of each wheel forms an arc from the top of travel to the bottom.

Not sure what you're seeing with respect to the pitch of the p/s wheel. Do you mean the camber?

By pitch, yes, I guess I mean camber. The top of the p/s wheel leans in relative to the bottom.

AzPete - yes, I do realize my garage floor is less than perfect and this may account for some/all of this. Which, is why I have moved the car and looked at this condition alot in the last week when parked on different "flat" surfaces (none of which are true level-and-flat, of course).

The air pressures in the tires are equal, and the sidewall bulge at the floor is slight and equal to the eye.

When standing behind the car and sighting down the p/s wheel lines, comparing the p/s rear to the p/s front, the tilt (lean in at the top) of the rear wheel can be noticed. Doing the same on the d/s, the conditions are different than the p/s.

MLM - thank you for that explanation. Makes perfect sense.

Well it might be good to take it to an alignment shop and have them measure the camber. It could be off.

What he said! Also have them check the mounting points for the axle to frame, and ensure they are correct. Why...in 1986 I purchased a new Turbo T-Bird and the rear axle was mounted incorrectly. It caused abnormal bearing wear where the drive shift was connected and began leaking. Ford replaced two bearings and then basically said not our problem. So, have everything under the car checked at the shop.

its a live rear axle. there is no camber to adjust.

I'm thinking everything is normal. I'm not sure about these cars as I've only had my 5.0 for a week, but most performance oriented vehicles are adjusted to sit level with ~175-200lbs in the drivers seat. I bet if you got in the car it would sit level.

Still... can't figure out why, with solid axle rear, that the rear wheels should be anything but parallel. I'll keep checking it out, and maybe get it up on a rack to see how the wheels hang.

Thanks for the replies. Did anyone really take a look at their 2010+ car to see what their rear wheels sat like?