Straight axle alignment

[rockracer]

How do you align your straight axles. Did you have to get it bent for proper camber  ?

[n49racer]

Yes. That?s how I aligned mine
Ted

[SPARKY]

We built one from scratch
and we cut slots in another heated,  bent and welded when we got the amount we wanted for bias tires vs radial it was built with

[Milwaukee Midget]

While not a straight axle, my MG does have king pins, and utilizes eccentric bushings to adjust camber.

[rockracer]

Well here's my dilemma.  I had speedway forged spindles, camaro brakes installed on a 32 chevy axle but the camber was too much.  Sent the vehicle over to an alignment shop that said they could bend it. Problem is that the bend looks terrible. 
I thought they would bend each side to even the camber.  The bend is near the driver's side leafspring mount,  looks uneven.
Now the tires look straight but this axle is embarrassing to look at.
Since then I've added a more modern steering box and a stabilizer to improve highway drivability. While it drives better than it did,  I think it could be better.  Starting to wonder if the caster could be off slightly on the driver's side. Never got any paperwork on the actual alignment.
Should I leave it be or start looking for another axle?

[Milwaukee Midget]

Never got any paperwork on the actual alignment.

That's a problem. That tells me that they don't know what they did, either.

If at this point its just the aesthetics that are causing you to lose you sleep, change it out. But when you do, check the camber before you try tinkering with it. If the new one is out, send it back.

Personally, I'd check the camber on the one you've got. You don't know what the numbers are, and your alignment shop was unwilling or unable to provide them. They bent your axle to achieve what you have, and if the shop messed it up, they're responsible to putting it to right.

Here's a quick way to get the numbers.

Park on a flat surface, grab a carpenter's square and a hand screw clamp, and set it up so it bisects the spindle, and don't disturb it:

DSCN1007 by Chris Conrad, on Flickr

Measure the distance from the top of the rim to the square, noting also the height, at which the measurement is being taken:
DSCN1014 by Chris Conrad, on Flickr

Top is 3 1/16 at 17 11/16 tall

Do the same at the bottom:

DSCN1011 by Chris Conrad, on Flickr

And the bottom of the rim to the square, same story - in this case, 3 1/16 @ 5 7/8:

Now in my case, I was looking to achieve neutral-to-positive camber, but I started out with negative camber and got to these numbers - which are close enough for the speeds my car achieves.

But let's change one of the numbers. Let's change the distance to the square on the top to 2 7/8, which I seem to recall is where I started - it's been a few years, but we'll give Pythagoras a call:

17.6875 - 5.875 = 11.8125 - there's your base, or "b"

Height of the triangle will be the difference of our 2 7/8 number (2.875) and 3 1/16 (3.0625) so  "a" = .1875

And here's where I cheat:

http://www.carbidedepot.com/formulas-trigright.asp

Enter the numbers, and bingo -

trig by Chris Conrad, on Flickr

Angle A is camber  .9 degrees


Check both sides. If they're out, I'd go give the alignment shop holy hell, and you can watch them squirm when you show them the math.

[Interested Observer]

?Park on a flat surface??

Chris, the likelihood of this being possible, side to side, and to the degree of accuracy necessary to get valid results is pretty poor.  A suggested modification to your method would be to put a good level on the horizontal leg of the square and adjust its position until that leg is level before taking measurements.

[Milwaukee Midget]

?Park on a flat surface??

Chris, the likelihood of this being possible, side to side, and to the degree of accuracy necessary to get valid results is pretty poor. 

IO, I've always respected your thoughts and opinions, so let me ask this - Are you implying that it's unlikely that a decent concrete driveway or garage floor is sufficiently level and flat to set camber?

I'm not trying to be sarcastic, but I would ask who poured your garage floor. I claim all you need is a nominal 8' wide width of floor sufficiently flat to set up perpendiculars at two points outside the outer track of the wheels in order to access the wheels for measurements.

I suppose one could attempt to confirm the perpendicularity with a laser level and roll the car into alignment between to squares.

But I'd be more concerned about deflection in the bushings and what craziness that might bring to the table than I would finding a flat surface onto which one could base two perpendicular planes sufficient to set camber on a solid axle car.

IO, I know you to be a smart guy - I've always respected your opinion - so I'll ask - what am I missing here? Have I misexplained something? My method provides camber angle with respect to the surface the car is sitting on. This is how I set up and ran 114 last September and the car tracked straight as a die.

rockracer - not intending to steal your thread here - but you want it right - so do we.

[johnneilson]

Concrete garage floors are inherently not flat nor level.
I had a shop built some years ago with a section for doing alignments, flat within 1/8"
That didn't last long,  after a couple years it settled and was out of spec.

I was doing road race car setups and corner weights so it became important to get it right.
The solution is 4 portable adjustable pads with weigh scales, a couple long aluminum straight edges and digital level.

With this setup and a two pole lift I could zero set a car in a matter of an hour or so.
In addition, when we returned from the races I was able to measure the setup for whichever track we ran and could duplicate for the next race of same configuration.

Your solution has a a margin of error in just using the floor, is it close enough, only you can answer that.

Best, John

Ohf, forgat to mention, check the wheels for runout, you would be surprised!!

[Interested Observer]

Chris:  It is apparent that we have had markedly different experiences with garage floors.  While I agree that if one?s floor is tantamount to a surface plate, there is no problem.  My comment was really not so much directed to you, but as a word to the wise for any less accomplished practitioners that might choose to utilize the method you have described.  In my experience, a typical floor is not likely to be very flat or level, and if measurements of camber are desired to an accuracy on the order of a quarter of a degree, a certain amount of care and consideration are needed.

Upon further consideration of my comment about using levels on the leg of the square, it would be necessary, in addition, to level the wheel pads from side to side, otherwise if the ?floor? is at a slant, that would introduce an offset to the calculated results.  This could be corrected mathematically, after measuring the slant, but probably easier to level the pads to each other.

Another approach would be to use a straightedge across the width from one square?s location to the other?s to verify the ?flatness? and degree of level. 

Not to mention the business of getting the weights correct, exercising the suspension, and rolling back and forth to relax the tire distortion.

I now note the recent post by Mr. Neilson whose floor experiences compare well with my own.  So- it?s crappy floors (2), nice floors (1)!

[rockracer]

I guess I could take it to another shop and have them give me a printed copy.  The place I had it done at was Val's alignment but it's under a new name now and been a few years.
If it turns out good on paper, I'll keep it for now.
Getting ready to install an Overdrive trans here soon.
Tried posting a pic but says too big of file.