Correcting positive camber in a Bugeye

DanLewis · May 28, 2013

The tires on my Bugeye are wearing faster on the outside edges, suggesting that there is excessive positive camber. I don't think it's due to any physical damage to the car since there's no evidence of damage and because both tires are exhibiting the same amount of wear in exactly the same way (see below). Is it possible that this might simply be due to coil springs that have weakened with age?

The A-arms (aka wishbones) and spindles were replaced less than a year ago with ones from a Midget when the car was converted to disc brakes. All new bushings were installed at the same time. Is there any chance that the later A-arms are a bit different (i.e., shorter) that might explain the positive camber?

I know that the Bugeye front suspension does not have any adjustment for camber or caster, although Moss does sell A-arm bushings with offset holes that allow one to adjust the camber. Does anyone have experience using these bushings to adjust camber in a Bugeye or Midget?

Thanks!
Dan

Trevor Jessie · May 29, 2013

I've not used the Moss bushings, but I made my own for the trunnion. This alone did not bring the camber into spec. So I then made some new trunnions with larger off set. Each side now has approx 1 degree of negative camber.

HealeyRick · May 29, 2013

Check the outer edges of the rear tires, too. Enthusiastic driving can cause outer tire wear.

DanLewis · May 29, 2013

Hi Trevor,

Trevor Jessie said:
I've not used the Moss bushings, but I made my own for the trunnion. This alone did not bring the camber into spec. So I then made some new trunnions with larger off set. Each side now has approx 1 degree of negative camber.

Do you know what was the cause of the positive camber you had before installing the offset bushings?

Dan

DanLewis · May 29, 2013

Hi Rick,

HealeyRick said:
Check the outer edges of the rear tires, too. Enthusiastic driving can cause outer tire wear.

I did think of that, but they're both fine. 'Guess I just don't drive as enthusiastically as others. :smile-new:

Dan

Trevor Jessie · May 29, 2013

My car is an early '58. I could not find anything that caused the the problem. I'm assuming it was just poor fitment of jigs at the factory and/or years of fatigue. I'm contemplating putting it on a frame rack and try it bring it closer to spec and adding bracing.

DanLewis · May 29, 2013

Trevor,

Trevor Jessie said:
My car is an early '58. I could not find anything that caused the the problem. I'm assuming it was just poor fitment of jigs at the factory and/or years of fatigue. I'm contemplating putting it on a frame rack and try it bring it closer to spec and adding bracing.

Curious. That's what I was wondering might also be the problem with my car. How did you go about determining how to position the second set of bushings? Was it trial and error? Did you have to put it all together, check the camber, then do it all over again? :grumpy:

Dan

Trevor Jessie · May 29, 2013

I used basic geometry/trigonometry to determine how much it needed to move. I used a "digital level" app on my smart phone to measure the camber at rest.
I knew that my offset trunnion bushings were not going to offer enough offset to put me in negative territory, but I thought they might reduce the tire wear. But I was not happy with the result so I made the offset trunnions. Technically, the trunnions I made are prototypes and I intend on making more "polished" versions in the future after these have some more time to tested/inspected.

DanLewis · May 29, 2013

I read today that camber can be affected by tire and wheel size. I have 175/70 radials mounted on 13x5" alloy wheels with an offset of 20. Does anyone know if this represents a sufficient departure from the stock wheels and tires to account for the positive camber?

Dan

Trevor Jessie · May 29, 2013

I'm not clear on how tire/wheel size can affect the static camber. Can you direct me to a picture or description?

DanLewis · May 29, 2013

Hi Trevor,

Trevor Jessie said:
I'm not clear on how tire/wheel size can affect the static camber. Can you direct me to a picture or description?

I wish I could. I don't remember exactly where I read it, and trying to find it again now with Google hasn't worked. It was something on the 'Net, and of course I guess we can't always believe something just because it's on the 'Net. :smile-new:

I did find a discussion in a book (see https://books.google.com/books?id=V3STrysMNjQC&pg=PA102&lpg=PA102&dq=adjustable+camber+bushing+mg+midget&source=bl&ots=p6HS_fdUig&sig=1Y1Vsvetfgtm0cpVEMjsko22TKc&hl=en&sa=X&ei=2rWmUcKUN8agiAL0h4DIAw&ved=0CEQQ6AEwBA#v=onepage&q=adjustable%20camber%20bushing%20mg%20midget&f=false) that says that changes in ride height, roll stiffness, and car's weight can all affect camber - although admittedly that's not what I was asking about. If the suspension geometry keeps the same degree of camber while the wheel moves up and down, then I suppose tire and wheel size shouldn't have anything to do with camber. Would that also be true of wheel offset? I.e., if the front wheels are offset a bit more away from each other, would that affect it? (I suppose if it did, the effect would be towards negative camber rather than positive.)

I'll keep looking and let you know if I can find the reference.

Dan

Trevor Jessie · May 29, 2013

The camber does in fact change throughout the suspension travel, so if your car has been lowered with shorter springs then the static camber is altered from stock.

Trevor Jessie · May 29, 2013

Offset and tire size will alter contact patch and amount of wheel scrub.

DanLewis · May 29, 2013

Trevor Jessie said:
The camber does in fact change throughout the suspension travel, so if your car has been lowered with shorter springs then the static camber is altered from stock.

I don't believe the car has ever been lowered, but wouldn't the same thing occur with aging springs? But wouldn't that cause more negative camber than positive?

Dan

xkejoe · May 30, 2013

run your hand across the tread of the tire. if it feels smooth one way and rough the other way it is a toe in issue. excessive toe causes tires to feather edge, and both tires wearing on the outside could be caused by too much toe in.

DanLewis · May 30, 2013

Hi Joe,

xkejoe said:
run your hand across the tread of the tire. if it feels smooth one way and rough the other way it is a toe in issue. excessive toe causes tires to feather edge, and both tires wearing on the outside could be caused by too much toe in.

I did have a problem with toe-in, which I believe I have since managed to correct. Anyway, I've ordered a camber gauge so I can determine how far off the camber is before taking any corrective action. If it's not far off, then maybe the tire wear was due to the previous toe-in problem.

Thanks!
Dan

AN5Sprite · May 30, 2013

xkejoe said:
run your hand across the tread of the tire. if it feels smooth one way and rough the other way it is a toe in issue. excessive toe causes tires to feather edge, and both tires wearing on the outside could be caused by too much toe in.

xkejoe makes a very good point.

As for front springs. There are at least 4 different variations. They got longer as the years went on and weights increased. the free-length of Bugeye springs is supposed to be 9.4", later they went to 9.59", 9.85" then 10.2". I would think that the longest versions could help contribute to a positive camber situation if used in a Bugeye.

I had a car that had a tweaked frame rail and excessive negative camber on that side. When trying to figure out what was going on noticed that the my springs were short at about 7.5". Removed those, replaced with a set of the 9.5" variant and most (not all) of my negative camber went away.

Also did an alignment at that time and cured most of my tire wear issues. 4 jack stands, some string, a ruler and some patience...

I still have a set of 7.5" long aftermarket front springs for sale if anyone is looking to lower their car, PM me.

Jim_Gruber · May 30, 2013

Steve,

VB had an issue with spring mislabeling about 10 years ago. I ordered a set of springs for Bugsy I my '68 Sprite and they turned out to be a set of RB Springs of the 10.2 variety, labelled as being correct for a '68 Spridget. Letting Bugsy down off of the jacks I had what appeared to be the first Off Road Sprite. Tire / Fender Gaps went from almost nil to 1 1/2-2". Reordering another set, I received the exact same incorrectly labelled 10.2" Springs. I ended up reordering BE Springs and that got me back to being a little lower than normal with a lowering kit installed. And yes, alignment with a long string, ruler, and jack stands fixed alignment issues.

As a rule of thumb, Frank C. used 15 1/2 threads exposed on the Tie Rod End as getting you in the ballpark for being correctly aligned.

markberry · Jun 2, 2013

DanLewis said:
The tires on my Bugeye are wearing faster on the outside edges, suggesting that there is excessive positive camber. I don't think it's due to any physical damage to the car since there's no evidence of damage and because both tires are exhibiting the same amount of wear in exactly the same way (see below). Is it possible that this might simply be due to coil springs that have weakened with age?

View attachment 27446 View attachment 27447

The A-arms (aka wishbones) and spindles were replaced less than a year ago with ones from a Midget when the car was converted to disc brakes. All new bushings were installed at the same time. Is there any chance that the later A-arms are a bit different (i.e., shorter) that might explain the positive camber?

I know that the Bugeye front suspension does not have any adjustment for camber or caster, although Moss does sell A-arm bushings with offset holes that allow one to adjust the camber. Does anyone have experience using these bushings to adjust camber in a Bugeye or Midget?

Thanks!
Dan

Hi Dan,
my Bugeye has some previous frame damage that I correct with a set of Speedwell offset, upper trunion bushings. They give you about one degree of camber adjustment. I think if I truly wanted to fix the problem perfectly, I should get the offset lower wishbone bushings that Moss offers.
regards
Mark

Graham Heath · Aug 18, 2015

I am new to the forum and have noticed your post regarding negative camber trunions. I have a set of step files (which I am happy to share) for cnc production but not the tool path, it is quite expensive here (in Australia) to set up a cnc machine for very small production. Did you make your own offset trunions? ...if so, how did you do it?
BTW, I am neither an engineer or a machinist!

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Correcting positive camber in a Bugeye

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