Why 2.6 deg. camber just on one side?

tiwebber · 06-04-2006, 09:33 PM

The camber on my cars wheels is as follows :
Front Left = 2.5 degrees negative camber
Rear Left = 2.6 degrees negative camber
Front Right = 0 degrees
Rear Right = 0 degrees

I measured it using a carpenters level and a little trigonometry. I measured toe and find that both the rear and front have no toe at all - ie.wheels are pointing straight forward as best I can tell ( using http://www.allpar.com/fix/alignment.html method).

I intend to make the camber ( or lack of) on the right of the car match the left because the rear right side of the tire is rubbing and because it seems to me I would want them to match. The car does not pull at all right now when driving.

My question is why would the PO have put 2.5ish negative camber on the left of the car and not the right side? Also, if I adjust the camber on the right to match the left should I expect the toe to change from the current "no toe" state? I have read that toe changes when camber changes but I cant understand why that would happen. Would'nt an equivalent change in camber on both wheels on the right side of my car just cause the wheels to lean towards the car while leaving them pointing straight forward as they are now?

Vipergrün · 06-04-2006, 10:36 PM

Those numbers, if correct, are whacked and appear to be setup for circle track racing or something.

I'd get her to a pro quick. Also, I don't think I have ever seen a stock car with that much negative camber in the front. You sure about those settings?

tiwebber · 06-04-2006, 10:45 PM

I guess I am less sure now than I was when I posted this data but I did measure twice and simply if you stand a level vertically from rim to the ground it touches both tires on the right (ie. cant touch the rim because the tires are too far out) but can touch the rim on the left. A visual inspection from the rear also indicates the left has negative camber while the right has none.

The PO used the car at the track alot. It was a track in Vancouver BC but I did'nt get the name.

Vipergrün · 06-04-2006, 11:01 PM

Sounds really odd, Tim... Typical setup would be like 2 degrees neg rear and 1-1.5 neg front. I'd still be curious how there is that much neg up front without mods.

cheers
-Brad

tiwebber · 06-04-2006, 11:17 PM

I'll measure again. My method (using a carpenters level and a ruler and some trig.) is probably very error prone.

In any case lets just say the left is negative and the right is neutral. Would making the right negative camber to match the left have any affect on toe?

ChrisBennet · ChrisBennet's Garage

Sounds like the car is on a tilted surface. If you back the car into the same spot do the readings change?
-Chris

Paulporsche · 06-05-2006, 05:54 AM

How old are the tires? Can you see a lot of wear on the inside of the lefts?

Chuck Moreland · 06-05-2006, 08:04 AM

Quote:

Originally posted by ChrisBennet
Sounds like the car is on a tilted surface. If you back the car into the same spot do the readings change?
-Chris

Bingo. You must be on a truly level surface to take measures.

Level to the eye is not good enough. It must be level within about 2 mm. Then your measurement technique must be accurate and repeatable.

Try turning the car around and taking measures in the same spot. Did the camber move to the other side?

Yellowbird RS · 06-05-2006, 08:08 AM

yes! oval races

tiwebber · 06-05-2006, 09:59 AM

I used my garage floor. I even measured it and it was level on one side but I checked it again and the level varies. Some spots it slopes up to 2 degrees. So, now to find a level spot for re-measurement. Indeed the camber changes when the car is turned around. THanks everyone. I'll find a level spot and post the data again.

ChrisBennet · ChrisBennet's Garage

Garages are usually sloped for drainage.
-Chris

tiwebber · 06-05-2006, 08:37 PM

I re-measured camber on a flat surface and turned the car around and repeated and got the same results - I think they are still questionable.

Left Rear - 1.6 deg.
Right Rear - 0.7 deg.
Front Left - 2.0 deg.
Front Right - 1.2 deg.

My goals is to increase negative camber on the Right Rear to match the left rear so that my tire will fit in the wheel well. My first question is will increasing negative camber on the right rear wheel have any affect on toe? Second question is "how often do folks with old non-adjustable spring plates do corner balancing?" Must be expensive to get a shop to do it given you have to re-index the t-bars everytime you want height adjustment in the rear?

I am going to get (or try myself first then get...) a full alingment after I replace my spring plate bushings but for now I just want to try to increasing negative camber in that right wheel.

Here is my camber measurement method.

gumba · 06-05-2006, 09:17 PM

You need to check the level for accuracy. Take the level off the ruler and put it on a flat surface, then turn it around and see if it reads the same. It looks like the ruler is at the outer edge on the bottom, but your not reading it at the outer edge at the top. All this will throw the reading off.

Chuck Moreland · 06-05-2006, 09:26 PM

Quote:

Originally posted by tiwebber
I re-measured camber on a flat surface and turned the car around and repeated and got the same results -

How do you know the surface was level? Level, not just flat.

tiwebber · 06-05-2006, 09:39 PM

Quote:

You need to check the level for accuracy. Take the level off the ruler and put it on a flat surface, then turn it around and see if it reads the same. It looks like the ruler is at the outer edge on the bottom, but your not reading it at the outer edge at the top. All this will throw the reading off.

I did check the level against itself and another level and its seems fine. I also checked if there would be a difference by reading at the outer edge of the wheel at the top (which means the bottom is suspended by my hand) and the difference might amount to between 0.1 to 0.2 degrees.

tiwebber · 06-05-2006, 09:52 PM

Quote:

How do you know the surface was level? Level, not just flat.

I have a 4' level that I used to check it. I took a number of readings both across sections of the car where the wheels were measured and I also measured lengths parallel to the car (though I dont think that matters too much) and all readings were quite level. Maybe it was out by 1 or 2 16's over 4 feet which is approx. 0.15 degrees. Then I turned the car around on the same spot and re-measured and got the same readings which gave me more confidence. I gather though that these readings dont sit well with anyone so I guess I should get a professional to verify or find another measurement method to double check.

Chuck Moreland · 06-06-2006, 07:58 AM

I use a water level. I think this is more accurate than a bubble level and a long straight edge. Error in the bubble level is multiplied by the length of the straight edge, not so the water level.

A water level is a simple length of clear plastic tubing, about 1/4 inch id. Fill almost completely with water and secure it in a "U" shape with the vertical portions on top of the points you want to check for level. I secure the tubing to two jack stands to hold the ends.

Measure from the water line to the ground. If the height of the water is the same, the points are level. If not, you can shim using vinyl floor tiles. These are about 1/16 inch thick and you can stack as needed.

This technique is equally accurate over any distance.

Chuck Moreland · 06-06-2006, 08:03 AM

For actually measuring the camber, I use a digital level. It's easier and more accurate than a bubble level, which requires carefully aligning the bubble and taking the measure simultaneously, and introducing two points of error.

If you don't want to get a digital level, use a plumb bob made of thread instead of the bubble level. That way you free up the hand that was trying to adjust the bubble level, the thread just hangs by itself - perfectly vertical! Measure from the thread to the top and bottom of the wheel.

tiwebber · 06-06-2006, 10:42 AM

Quote:

I use a water level

Thanks for this Chuck. This is exactly what I am going to do.

Quote:

use a plumb bob made of thread

I am going to try this too. I suppose you could just tape the thread to the top of the wheel and let the plumb bob hang to the bottom of the wheel so you free up your hands for measuring?

Quote:

Not to take away from the sophistication of the advice being offered here

Indeed. I think you can see this. Here's a link where I posted some rear pics that are not too bad. They are down the link a bit.
Tire Rub - Wheel Question
I am just trying to get a negative camber measurement for the right rear wheel and adjust it so it fits in my wheel well. Once I have the final camber measurement, I can always set it (or specify for someone else to set it) at that measurement in the future so that the tire fits. Maybe when I am more experienced I will trust my eye.

Also, if anyone knows if adjusting/ adding negative camber to one rear wheel will affect toe that would be good info. Thanks all.