Need a little alignment advice

70 Cuda, new components, offset UCA bushings, primarily street car.

Had the car aligned today and static, we got +2.4* caster and -.5* camber on both sides. When I sat in the car, it was still +2.4* caster, BUT the left camber went to -.2* and the right went to -1*. Toe stayed at 1/16".

The car now has a good amount of drift to the right. About 50% of the time there is only myself in the car and then about 50% of the time I have the wife with me. Obviously I need to make an adjustment and the alignment guy is cool and ready to make whatever adjustment we decide on. I just don't know where to set it now.

I didn't think that putting my 190lbs in the seat would affect the readings that much. But they did. And I don't know how much the wife's X number of pounds will affect it to boot.

I am not real particular on the alignment specs. I would just like the car to go down the road straight with either just me or with me and the wife in the car.

What adjustment would you recommend for this?

Power steering? If so the valve on top of the steering box is off center.. Raise the front end off the ground,, start there car, see if the steering wheel kicks to the right

Yep, power box that I just got back from Firm Feel. I think the issue is that the camber is off side to side with me in the car. And I was just curious if anyone else has dealt with this particular problem.

Reputable alignment shops always stagger the caster (or camber) side to side to compensate for the road crown. Then they road test the car to make sure. Doesn't sound like they knew what they were doing IMHO.
When that is done correctly, it will track straight.

I ask for as much positive caster as can be obtained and zero camber & 1/16 to 1/8 of toe in. Most shop regs wont let a customer sit in the car while it is on the rack so I set my weight in barbells on the pass side then have the tech pull em over to the drivers seat when he exits the vehicle after he drives on the rack & some machines compensate for drivers weight (talk to your man). You may or may not want to have the wifes' weight in barbells on the pass side. ahead of time I get the toe straight and the camber to zero & the ride height (tbars) where I want (tire fit looks good in the wheelwell) then I drive it several miles then recheck/readjust the ride height as needed then drive to the shop. 1/2 tank of gas/tires aired up. jounce/bounce to confirm the ride height (it will settle) then I tell him not to change it but he may if needed SLIGHTLY adj it side to side to get both sides even.

Dave, I typically do the same as RapidRobert. As long as you're ending up with your ride height where you want it with your weight in the car, it shouldn't matter if you add weight before the alignment and level up, or level up before and add t-bar adjustment to compensate after the alignment.

I don't know if it makes a difference, but I generally try to match specs side to side and I don't worry about road crown. I haven't really noticed a pulling or drifting problem.

first thing to do is criss cross the front tires. the pull could be the tires. a difference of .1 will not cause a pull. unless the road is that crowned. Car will drift to the side with more positive camber, but caster is the opposite, it will go towards the more negative reading. A tenth or 2 difference won't cause a pull. I always set the driver side a touch more camber to compensate. factory specs called for .25 more camber on driver side.

I have been driving the car for a couple of months so that everything could settle in, especially the ride height. I will switch the tires, but they are new so that shouldn't be the issue.

I have read and re-read the alignment threads, but didn't see much about having weight in the seats, so I was surprised that it had as much impact as it did.

+2.4* caster was all we could get, even with the offset bushings. But that didn't change when I put my butt in the seat.

The big surprise for me was that the pass side camber went from -.5* to -1*. Added to the driver's side change from -.5* to -.2*, that is a difference of .8* camber side to side. That is the likely culprit here, isn't it?

The alignment guy has many years experience (although not on Mopars) and seems ready to do what it takes to get this done. So sitting in the car shouldn't be an issue.

Should the wife and I go and get readings with both of us in the car and then with just me in the car and kinda split the difference in settings? Seems a little convoluted to me, but if that is what it takes then I would do it.

Thanks for the input, guys. I appreciate it.

New or not, cross the tires. They can cause a pull right off the bat.

Put the weight on the driver's seat and recheck ride height then recheck the specs.

Will do.

Camber will not have too much of an effect on drifting from one side or the other. Caster does though. I always try to set them up with .5 degree less on the left to compensate for road crown.

yes the weight info does sound potentially convoluted. the tire man further above sounds convincing so I would check that potential. Did it drift before or NA?. I would talk to the alignment guy again or even just call another shop (maybe a Mopar shop) tho I wouldn't think that would be real critical as alignment is alignment (for the most part) & tell em what happened (no names will likely get a better chance of good info) & there are alot of heavy bodied customers these days so it should not be a fresh never dealt with before issue. Post how it turns out.

Welllllllll.......the rest of the story is that this is the second shop I have had it at. The first didn't even get it close and they worked on it for hours. There just aren't any shops around here that have done any old Mopars.

This guy is independent, has years of (other) brand experience, and says he is ready to do what it takes to get the job done. We'll see.

I didn't get a chance today to try the suggestions offered here, I hope to tomorrow. And then I'll give the alignment shop another shot.

One last piece of info; I have 318 bars in the car. They are supporting an al. head Hemi and 518OD. Obviously way more weight than they were designed for. The ride height is good and the adjustment bolts are still below the LCAs. But they may let the nose drop more than normal when the driver climbs aboard. Which may then affect the adjustments more than normal.

I will try to influence the results with the suggestions offered above and then, if all else fails, consider installing heavier bars.

You might have someone measure how far the left & right sides move down when you and or you & passenger enter the vehicle. Maybe the 318 bars are too light but I would think not an issue since you were able to crank em up to a good height. Maybe it wouldn't hurt to weigh the front end & see exactly how much weight is on the bars. whatever is causing the "drifting" I think is critical. On my 65 dart SB they kept the RH where I set it & set the camber to zero but they said the caster was way different on one side likely from something bent & I had told em to get as much positive caster as they could. it floated down the street perfect (power st). my next one I'm gonna level it myself (utube), likely "string it" then start with turning the cams for max caster then bring the rear one out till I get zero camber (carpenters 2 ft level glued vertical to the rims) & let the caster fall where it may. If I did do caster there are some interesting vids using floor tiles with salt inbetween em for easy turning. On my dart I used some monstrous circle track tbars (all I had at the time except /6 bars) & it rode awesome (+ 003/003 SS rear springs).

Unless you are going for a road race vehicle the weight is not the issue. We used to set the drivers side 1/2" higher than the right to compensate since most of the time a car only has one occupant. Adding weight rarely affects caster and it's caster that affects how straight a car tracks all else being in spec.

Can you get a car to pull with camber adjustments? Yeah you can but you have to slant both wheels to one side to do it. So it's no longer close to preferred spec.

Your problem is either equal caster or too much caster on the left. It could also be a tire issue as tires are not only never round they are also conical to some degree.

There are two components that you guys are discussing and it's important not to get them confused.
1. Spring force - how much weight the spring is resisting
2. Spring rate - How the spring reacts to a change in weight or force.

In this particular case, the smaller diameter bars have a lower spring rate and therefore will deflect more with a unit change in force, while a larger diameter bar of the same length will deflect less.

The general equation is F = KX, where F is Force, K is the spring rate and X is the amount of deflection. It's easier to follow if you think of a coil spring, like a valve spring.

The torsion bar is exactly like a coil spring, except the coil has been straightened out. Chrysler engineers liked to do their own thing so they talk about the combined effect of the torsion bar and length of the control arm, they call this wheel rate. That's the number of lb force it takes to raise the wheel 1".

The important takehome from this discussion is that while the smaller diameter bar will support the load, the suspension will deflect more with every additional pound it is asked to support.
That's no matter how much the bar is already supporting.

R.

Boy, I am with you on the out-of-round tire thing. We balance a fair amount of tires and I am shocked at how many are not even close to being round. I will swap my front tires side to side, hopefully tomorrow and drive it.

And it's interesting your point on the camber having little affect on drifting to one side or the other. Because the camber changed a substantial amount with my weight in the car.

But just as you noted in your post, the caster changed only slightly. Both sides, with and without my butt in the seat stayed in the +2.3* to +2.5* range.

As I said, first I will swap the front tires and see what happens. If that doesn't move the problem or fix the problem, then I might pull a bit of caster out of the driver's side. It has to go back to the rack anyway, so I can't really do it any harm.

Thank you!

post how it turns out.

SUCCESS!!!

Rather than switch the tires around, I just bought a new pair of Michelin Defenders. Good tires, very round and neither one took more then 3/4oz weight, total.

But that wasn't it, it still drifted right.

So with Guitar Jones' advice that a right drift would be caused by the left having too much caster, I hit the interwebs and gleaned enough info to try a bit of experimentation.

I marked the position of the cam bolts on the left side and moved the front one in just a bit. Re-installed the tire and test drove. It was better. So after a couple more small moves inward on the front cam bolt, it goes down the road good and straight.

Thanks guys for all the help, especially Guitar Jones for the specific info without which I wouldn't have known just what to tackle.

Now, one last question; do I need to do anything with the toe? It didn't take much movement on the cam bolt, but it did have to move and that does affect the toe, doesn't it?

Thanks again, guys!

You sound happy!

You really should put it on an alignment machine and check. By moving one cam bolt you have changed the camber as well. If you had moved one bolt in and the other bolt out the same amount you would have changed the caster and kept the camber the same.

I would suggest checking it to see where it's at. If you need to make an adjustment just keep the caster at the current settings.

And you are welcome, glad to help.

So, impacting the toe isn't the issue, but impacting the camber is. I see what you mean.

I can mark the rear cam bolt location, move the front one back out a bit and then bring the rear out a bit. It may not be perfect, but I can trial and error it enough to get it to go down the road straight like it does now. Then I'll drive it awhile and see if I want to put it back on the rack.

Wheel alignment has always been one of those things that I had no real grasp of the details. Through this process, I have not only gotten the Cuda to go down the road straight, but I have learned a lot about camber and caster and what they do.

again