Stock K Member misaligned??

[TimAlan]

I had a set of wheels installed and it became apparent that the driver's side wheel sticks out about 1/4" wider than my passenger side wheel. Everything else is equal.. 285/35/20 on 20x10 wheels.. the camber is the same on both sides and there's no difference in the toe according to the alignment sheet.

Is it possible that the car came from the factory this way? The car has never been in a collision, and to the best of my knowledge the K Member has never been removed or loosened for any reason. Any other way this could have occurred and what would it entail to fix it? My car is also under warranty. Would this qualify as something I could take up under warranty?

Thanks for the help.

Sponsored

 

[DickR]

Are you absolutely sure the wheels have the same backside spacing? It is conceivable that one wheel's mounting surface wasn't machined properly.

You might try using a finger to compare the gap between the tires and the strut first. If these seem different then remove the wheels and compare the measurements between the mounting surface of the wheels to the sidewalls of the tires to get a good idea whether the backside spacings are the same.

This assumes that the wheels have the same claimed offsets and claimed and actual widths. You can get a good idea regarding the width by comparing the actual section width of the mounted tires.

EDIT Having said the above I didn't consider that the alignment might have picked up any wheel differences.

 

[BMR Tech]

It is definitely something that happens on mass produced vehicles, and is one of the reasons I am not "sold" on telling everyone to perfectly center any part they can on a car without ensuring the opposing end of the car is "perfectly" centered.

My experience on my 2015 is that the engine centerline was shifted a little over 1/8" to the passenger side in comparison to my "perfectly centered" rear IRS assembly. When installing our front k-member set-up, I spent the time to perfectly align the engine and the front arm pick up points to match the rear IRS so that the front and rear are 100% identical, laterally.

1/4" seems a little on the aggressive side. When you get a chance I suggest putting the car up on ramps and taking some precise measurements.

 

[BmacIL]

The rear subframe does have that much allowable movement, but Kelly [MENTION=9985]BMR Tech[/MENTION] made excellent points above. From a driving/handling perspective, you do want to make sure your front and rear don't have wildly different centerline planes (1/4" would fall into that).

 

[Brian V]

From what exactly would 1 be measuring to guage distances to find centerline to insure that 1 may be able to perform adjustments as needed ?

I am asking because I just trued up the rear crossmember ie subframe with the Steeda alignment dowels and may have moved centerline for both the front and rear .. just trying to get specifics to what exactly I would be looking for underneath to get exact measurements ...

 

[BMR Tech]

From what exactly would 1 be measuring to guage distances to find centerline to insure that 1 may be able to perform adjustments as needed ?

I am asking because I just trued up the rear crossmember ie subframe with the Steeda alignment dowels and may have moved centerline for both the front and rear .. just trying to get specifics to what exactly I would be looking for underneath to get exact measurements ...

For me, I am most concerned about my driveline. The relationship of the engine centerline and the rear pinion centerlines. The suspension pick-up points come secondary for me, personally.

So what I do is I measure the width across from the chassis mounts - then find the centerline / of the engine and the rear pinion.

In some cases it is easy to do the front - as you can just put a deep socket on the crank bolt pulley and then run a tape across between the "frame rails". The rear can be a little more tricky, but the way I do it is I measure the distance between the front two main IRS subframe mounts (blue bolts) and then compare to the center of the pinion.

 

[Brian V]

Thank you [MENTION=9985]BMR Tech[/MENTION] ..

 

[TimAlan]

Thank you all for the replies.

The back spacing between the strut & tire is equal on both sides. After checking the spacing a little further, it might not be 1/4", but it's visibly noticeable from the front. I'll have to get it up on a lift to check it in the near future.

 

[DickR]

Thank you all for the replies.

The back spacing between the strut & tire is equal on both sides. After checking the spacing a little further, it might not be 1/4", but it's visibly noticeable from the front. I'll have to get it up on a lift to check it in the near future.

Where is the difference visible? That is "top of tire to fender above it" or some other location. With the car on a flat and level surface can you use a plumb bob or a level to give you a true vertical reference point for measurements? If you cannot find a level surface you could try measuring with the car facing one direction and then turned 180 degrees and measuring from the other direction and then average the measurements.

Since the camber is the same on both sides and you didn't mention any camber adjustment modifications other than Steeda springs I don't know how the K-member could be shifted that far without causing significant camber differences between sides but I'm not an expert by any means. This makes me wonder if it is just fender "width" and "mounting" tolerances?

 

[TimAlan]

Since the camber is the same on both sides and you didn't mention any camber adjustment modifications other than Steeda springs I don't know how the K-member could be shifted that far without causing significant camber differences between sides but I'm not an expert by any means. This makes me wonder if it is just fender "width" and "mounting" tolerances?

That's exactly why I'll be putting it on a lift and measuring it with my mechanic. However, as Kelly mentioned, it could be just something that came from the factory with a mass produced vehicle.

 

[BmacIL]

Where is the difference visible? That is "top of tire to fender above it" or some other location. With the car on a flat and level surface can you use a plumb bob or a level to give you a true vertical reference point for measurements? If you cannot find a level surface you could try measuring with the car facing one direction and then turned 180 degrees and measuring from the other direction and then average the measurements.

Since the camber is the same on both sides and you didn't mention any camber adjustment modifications other than Steeda springs I don't know how the K-member could be shifted that far without causing significant camber differences between sides but I'm not an expert by any means. This makes me wonder if it is just fender "width" and "mounting" tolerances?

The camber arm is mounted to the subframe, so camber can easily be in spec or identical on both sides and still be significantly shifted. The tolerances for the BIW aren't that big. The holes in the subframe are WAY too big, even to accommodate the variability of the BIW. FRAP is a terrible plant to work with.

 

[DickR]

The camber arm is mounted to the subframe, so camber can easily be in spec or identical on both sides and still be significantly shifted. The tolerances for the BIW aren't that big. The holes in the subframe are WAY too big, even to accommodate the variability of the BIW. FRAP is a terrible plant to work with.

I was thinking that the camber is controlled by the camber arm mounted to the subframe combined with the top of the strut mounted to the body and the location of the holes where the knuckle/spindle/hub mount to each other. I guess the subframe "mis" location could compensate for tolerances in the other parts.

Thanks,

 

[BmacIL]

I was thinking that the camber is controlled by the camber arm mounted to the subframe combined with the top of the strut mounted to the body and the location of the holes where the knuckle/spindle/hub mount to each other. I guess the subframe "mis" location could compensate for tolerances in the other parts.

Thanks,

In the rear, the shock does not have any effect on the geometry. All the control arms and links are mounted to the subframe, so alignment is independent of the subframe positioning.

 

[DickR]

In the rear, the shock does not have any effect on the geometry. All the control arms and links are mounted to the subframe, so alignment is independent of the subframe positioning.

Understand but isn't his problem in the front?

 

[HISSMAN]

It's funny that this came up because I actually measure the offsets and backspacing of any wheels that I buy when they arrive. The reasoning? I received a set of wheels (square setup) for a Jaguar we used to have in 2006, and I noticed that one side was not lined up, similar to what you are seeing. I put the OE wheels back when we were going to sell it and noted that they were lined up again. I measure the aftermarket wheels, and sure enough the mounting surface was 3/4 thicker on one of the wheels. Being that it was 3/4 off leads me to believe that it was a machining error as I don't know of anyone that makes wheel sizes in exactly 3/4 increments. Needless to say I was able to get a full refund on wheels that had 8K miles on them. Can't beat that, and I didn't have to list them for sale and deal with that.

Sponsored