Passenger Side Tire Sits Back Towards the Rear

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1. Now I AM confused, Twisted. I'm talking about the rear end. The front looks fine. Its the rear that sits too far to the passenger side. I always thought they align the front and the rear sits wherever it sits. Do they mess with the rear end too when they do an alignment?

2. Could have sworn i read a good answer to this on this forum just can't find it. Thought it had to do with the length of the differential but don't quote me on that. If it helps mine is off set by a 1/8 inch.

3. They use the position of the rear wheels to align the front.
   

   It may be doable but the tech should know about the odd wheel because he may need to compensate for it.

4. I see what you mean now. Is it normal for the rear to sit toward the passenger side or should I have someone check it out? I don't see anything bent or broken.

5. 

   G72Zed Veteran Member

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   It's been over a decade now that I built and set up my 72 Z/28 chassis. Going by memory here, so take this for what it is.

   My buddy helped me out on some of the things I wanted to try, as I have helped him out on his stuff. We were all over my Camaro trying stuff out and setting up it up. Many many things were "played" with, most worked, some didn't, some stuff we just could not tell. We argued allot. I screwed up the front end the first time around, that cost me.

   We had it mocked up, and using Intercomp scales started moving stuff around. When I was lining up the basic drive train, I centered the engine and trans like I thought I should, then noticed the "none parallelism" sure enough, loosen the trans mount, trans pulled to the passenger side, 1/2. Yep, engine/trans is offset by 1/2 in the frame to the passenger side to compensate for driver weight and L/R balance correction, at least that's what we saw.

   Next was lazering and plump bobing the rear end, yep, factory offset to the passenger side. I always looked at the rear end cover bolts (12 bolt) and rear bumper bolt/key lock to see if the rear was "centered" , well it was, but the pinion offset and the fact I think (take this with a grain of salt) GM did not want "warranty" issues with bad u-joints if there was not enough pinion angle if it did in fact line up on the horizontal plane, so a little (or allot, didn't matter, tires were skinny) factory offset made sure it had enough working angle to get the needles rotating nicely. Also noticed how the rear was not "centered" in the wheel openings. Might have been my car as GM was going on strike, and build tolerances where crappy!! Car was never hit, original, and rear frame measurements were out of whack.

   I think this might be some of the reason why you see "maxed tire sizes" have rubbing issues on the inner driver wheel tub, and hit the passenger quarter panel lip, some more than others.

   Well, needless to say, my rear end is "offset" in the chassis, some people ask why it looks pushed over to the driver side. Oh, the nightmare of compound angles!! drove me nuts.

   Hope this sheds a bit of light on this subject, I didn't "search" if this was covered before, if it has, I will delete this post.

   Lots of Pros on this site, if I am wrong and/or off line on my findings, or thinking, please correct me, this stuff above bothered me for years while the build was going on, it held me up big time.

   Thanks

6. Could be a few things...car was wrecked, the sheet metal is not exact from right to left. The mounting location slightly welded off spec. Etc...etc...it was the 70s. The more and more I work on my car I can see the sloppy tolerances

   The drivetrain is towards the passenger side is by design by a small amount. It looks to have been necessary for brake booster and steering components. This however is different then the rear not being centered. Even though the pinion is offset doesn't make the rearend off left to right. The factory wheels all have the same offset

   Last edited: May 18, 2017

7. G72Zed makes a great point about u-joint angles.
   A perfectly aligned u-joint is not the optimal design. (Needle bearings need to move!)

   I have a tweaked yoke on my differential and I can feel a slight 50 Hz vibration when the pinion angle is low (car loaded down for a trip) and I'm at an even cruise speed with no load on the driveshaft. (Yoke ears are a bit wide and it rattles back and forth a few thousandths of an inch.)

   Yes... the pinion seal and yoke replacement are in the planning stages.... For a few years now.
   It's one of those situations where every bit of slack throughout the drive line resonates at a very specific RPM and load. Not even noticeable 95% of the time.

   Engineering the differential to be slightly off-center provides for a 2nd dimension of u-joint motion when the horizontal plane is aligned and provides no rotational motion of the needles through the driveshaft's rotation aside from any movement provided by side-to-side offset.

8. Correct me if I'm wrong but, its sounds to me like saying 2 things.
   1: The whole drive train is purposely shifted to the right.
   2: There is some mysterious reason the factory actually wants a small amount of bind in the U-Joint! WTF?!
   Anyway, if it is normal and nothing to worry about that it sits over to the right, it still seems that an offset in the rear wheel backspacing would compensate for how the tires sit in the wells, make the car look correct and make the four wheel alignment job nicer. Unless, there is some good reason for having the front end sit to the right as well. Correct?

9. This is very disconcerting to me. I would like to know that when other drivers are behind my car, they don't see the right tire closer to the fender than the left. If this can't be then, we are all driving crooked Camaros.

10. I seriously doubt other drivers can see the 3/8 to 1/2 difference from behind. I have seen other guys on here order wheels with more backspacing and add a small spacer behind one rim to center the tires under the car. I can't see this hurting anything with trying to align the car. Shop that use lasers, clamp the lasers to the rims, not the car, so all four wheels get aligned. I use 4 jack stands and string. You won't be able to adjust the rear much, but you can loosen the U-bolts or T-bolts and push the rear over a little and tighten the bolts back. You won't get it to move much, but it may be enough to get the rear tires in the same plane with the fronts so that it tracks straight.

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Passenger Side Tire Sits Back Towards the Rear

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