Finally! 70 Roadrunner going to "the old guy" for its 2nd ever alignment. QA1 everything w/SPC UCAs

[biomedtechguy]

I had a lot of systems and parts replaced on my Roadrunner about 2½ years ago, and I had the all new front suspension aligned at a shop close to the shop that did the work on so many different things on my car.
About a year and a half ago, I noticed the car was "train tracking", following the depressions in the road parallel to the direction of travel.
There's an "old guy" (Mr. Jerry) who owns and works at a suspension and general mechanics shop near my house who is very conscientious about the quality of his work, and he knows "old school" MOPAR suspension alignment. I have brought my car to him since I've had it, about 9 years now, and I am happy with his work.
He's been short on help, so it takes time to get an appointment, but Thursday is my appointment.
I have QA1 everything, including the tubular K-member, and the only exception is the SPC UCAs, because they have so much adjustability, the lack of which was a complaint I had heard referring to the factory design UCAs and "cam key".
I'm also going to have him look at everything on the front suspension as a safety check, and see what is involved in connecting my parking brake to the rear disc brakes. The cables are run, but I think I needed to pick up my car for Cruisin the Coast and the rear parking brakes weren't connected.
I'm hoping that this alignment, now that all of the new parts and work I had done a couple of years ago have been able to "relax" will last for some time.
The train tracking had gotten so bad it wasn't really safe to drive my car.
Have any of you had this issue, and what adjustments were made (caster, camber, toe in/out) to fix it?

 

[pnora]

For what its worth most alignment specifications across all makes are very close to the same. Its not some special got to know mopars thing. It basicly finding a competent mechanic that knows what he is doing. Rare these days. Sounds like you have that guy. My 69 Charger ended up -.5 on camber +2.2 caster and 0.13 toe which is about 1/8 . I was wanting a little more caster and I have the offset upper arm bushings. With my desired ride height I had to settle for what I posted and the car drives perfect. With what you have I would try for the same as mine but try for 3 to 4 degrees on the caster.

 

[Hemirunner]

My car still utilizes the stock cam bolts on the UCAs as well as spherical rod ends. For drag racing, the more caster the better, but I’ve had so much caster dialed in the car would hardly take an interstate off ramp without me putting my body weight onto holding the steering wheel from wanting to center up.

 

[1 Wild R/T]

My car still utilizes the stock cam bolts on the UCAs as well as spherical rod ends. For drag racing, the more caster the better, but I’ve had so much caster dialed in the car would hardly take an interstate off ramp without me putting my body weight onto holding the steering wheel from wanting to center up.

Yes, with aftermarket parts you can go to far for a street car... With stock parts it's a challenge to get enough...

Thing is knowing where yu want to get to & getting as close as possible...

Stock we use offset bushings & keep an eye on strut rod bushings cause they can be to thick & limit caster...

Stock alignment numbers were based on bias ply tires & tire wear, they weren't concerned with performance & didn't have today tire technology...

Numbers to shoot for
Caster at least 3.5 degrees, that's enough for stabile high speed driving don't need more than 5, some modern cars use 7+ but it begins greatly increasing steering effort
Camber at least .5 negative, these days I'm leaning toward .75-1.0 since the tires on these cars tend to age out before they wear out I'll trade some tire wear for better handling...
Toe 1/8" toe in..

 

[70ChargerRT]

I had a lot of systems and parts replaced on my Roadrunner about 2½ years ago, and I had the all new front suspension aligned at a shop close to the shop that did the work on so many different things on my car.
About a year and a half ago, I noticed the car was "train tracking", following the depressions in the road parallel to the direction of travel.
There's an "old guy" (Mr. Jerry) who owns and works at a suspension and general mechanics shop near my house who is very conscientious about the quality of his work, and he knows "old school" MOPAR suspension alignment. I have brought my car to him since I've had it, about 9 years now, and I am happy with his work.
He's been short on help, so it takes time to get an appointment, but Thursday is my appointment.
I have QA1 everything, including the tubular K-member, and the only exception is the SPC UCAs, because they have so much adjustability, the lack of which was a complaint I had heard referring to the factory design UCAs and "cam key".
I'm also going to have him look at everything on the front suspension as a safety check, and see what is involved in connecting my parking brake to the rear disc brakes. The cables are run, but I think I needed to pick up my car for Cruisin the Coast and the rear parking brakes weren't connected.
I'm hoping that this alignment, now that all of the new parts and work I had done a couple of years ago have been able to "relax" will last for some time.
The train tracking had gotten so bad it wasn't really safe to drive my car.
Have any of you had this issue, and what adjustments were made (caster, camber, toe in/out) to fix it?

I’m interested in what your numbers will be.

 

[biomedtechguy]

I’m interested in what your numbers will be.

I'll post them.

For drag racing, the more caster the better, but I’ve had so much caster dialed in the car would hardly take an interstate off ramp without me putting my body weight onto holding the steering wheel from wanting to center up.

I definitely plan on 1320 rips, but a good bit of cruising as well,
BUT
"centering up" is what is lacking, and I appreciate all who replied with suggestions!

 

[WileERobby]

What these ^^ knowledgable gents just said. I do -0.5 camber, +2-3 caster, 1/8 toe-in on my cars.

 

[nativefx]

I'm using the newer style SPC forged upper control arms on my 68 charger. Took it in for alignment and got these results. I asked for -0.75 Camber, +6* Castor and +0.03/+0.03 toe-in. Unfortunately the "tech" said in order to get the 6* castor he had to adjust the front strut rods??? But the strut rod lengths are not even the same side to side. So now my wheel is not centered on the passenger side, but I have plenty of clearance on the driver side, which doesn't make any sense. I'm interested to see what results you get, as I need to re-adjust my strut rods and remove any tension on the lower arm before finding someone else to possibly align my car. I'd like to know how much caster I can actually expect with adjustments only on the upper arms?

 

[RemCharger]

I'll post them.

I definitely plan on 1320 rips, but a good bit of cruising as well,
BUT
"centering up" is what is lacking, and I appreciate all who replied with suggestions!

Think of your caster like a motorbikes forks.
You get stability with some rake. But could you imagine if they were straight up and down? That's 0 degrees caster. Death wobble type stuff.

 

[pnora]

I'm using the newer style SPC forged upper control arms on my 68 charger. Took it in for alignment and got these results. I asked for -0.75 Camber, +6* Castor and +0.03/+0.03 toe-in. Unfortunately the "tech" said in order to get the 6* castor he had to adjust the front strut rods??? But the strut rod lengths are not even the same side to side. So now my wheel is not centered on the passenger side, but I have plenty of clearance on the driver side, which doesn't make any sense. I'm interested to see what results you get, as I need to re-adjust my strut rods and remove any tension on the lower arm before finding someone else to possibly align my car. I'd like to know how much caster I can actually expect with adjustments only on the upper arms?

View attachment 1463007

Something does not sound right. To be clear you also have aftermarket adjustable strut rods? Unless you have something bent what was done does not sound right. Now you need to start all over. For what its worth you do not need more than 4 degrees of caster.

 

[1 Wild R/T]

Something does not sound right. To be clear you also have aftermarket adjustable strut rods? Unless you have something bent what was done does not sound right. Now you need to start all over. For what its worth you do not need more than 4 degrees of caster.

Yup, something ain't right, likely a bent spindle or lower control arm an yeah 4-5 degrees is plenty... Hell the are plenty of Mopars running around with 2.5-3 that drive great...

 

[ckessel]

Gotta make sure the thrust angle, which is the measurement between center of spindle to center of axle, is the same. Adjustable rods can help on that plus there are shims available to put between the front spring hanger and the uni-body. The way you describe the tech's adjustment makes me think the t/a is not right. That also points out other problems like Randy is mentioning and/or structural/diff housing problems.
These adjustments will take time to get correct so you would be doing wishful thinking if you expect a $69.95 alignment to get you what you want.

 

[1 Wild R/T]

Gotta make sure the thrust angle, which is the measurement between center of spindle to center of axle, is the same. Adjustable rods can help on that plus there are shims available to put between the front spring hanger and the uni-body. The way you describe the tech's adjustment makes me think the t/a is not right. That also points out other problems like Randy is mentioning and/or structural/diff housing problems.
These adjustments will take time to get correct so you would be doing wishful thinking if you expect a $69.95 alignment to get you what you want.

FWIW my alignment guy charges about double that, and his gauges were made in the sixties... But he's being using them since they were new... Setting up track cars, street cars, road course cars.... He knows about performance & handling, I have been using him for close to thirty years, when he retires I'll have to start doing my own alignments again cause I haven't seen a tire shop alignment that impressed me yet...

 

[#41]

Why do people want 6 degrees of caster? Trying to overcome power steering to center itself more? I would like to understand.

 

[1 Wild R/T]

Why do people want 6 degrees of caster? Trying to overcome power steering to center itself more? I would like to understand.

Caster when the wheels are turned essentially becomes camber, and positive caster becomes negative camber on the inboard tire & positive camber on the outboard tire... Which means the tires are both in better contact providing more grip which equals better handling... Without sacrificing tire wear...

 

[1 Wild R/T]

Just did a quick search of the web... This explains it better than I can...

Wheel Alignment: What Is Caster? - Auto Quarterly

In this article, we’ll be talking about caster and how it affects your car’s driving feel and tire wear. Your car’s alignment is important, and knowing how the adjustments affect driving can save you a lot of time.

autoquarterly.com

How Caster Affects Cornering​

Caster angle primarily affects a car’s steering feel. A car with more positive caster angle will be harder to turn than a car with less positive angle. That is often desirable for two reasons. The first is that the stiffer feeling means it’s easier for the car to realign after cornering. The steering wheel returns to center faster, which leads to increased safety.

The second reason is that it increases traction in a corner. Sports cars, or other cars that are expected to be driven with more enthusiasm, often have higher amounts of positive caster so that they stay more planted in the turns.

Return to Center​

To understand how caster affects a car’s ability to straighten out, imagine pushing a shopping cart or rolling an office chair. When you push a cart or chair, all the castering wheels align with the direction you are pushing.

Your car is the same way. As you accelerate, the wheels want to naturally align themselves with the forward momentum. Most cars have fixed rear wheels, so the front wheels are the only ones that can turn. When you increase the caster on the front wheels, they want to return to center faster, which makes controlling the car easier. If you look at shopping carts, you’ll notice that the front caster wheels have a lot of positive angle for the same reason.

Negative Caster​

A car with a negative caster will want to wander instead of straightening out as you accelerate out of a corner. Or worse, it will want to lock in a certain direction. You can get a feeling for what happens when you have a negative caster if you give a shopping car a good shove backward.

Chances are it will go every direction except straight because the wheels won’t be able to align with the force. They will lead instead of trailing like they are supposed to. As you can imagine, that’s not a desirable way to drive a car.

More Traction​

The other advantage of a positive caster in the handling department is that a positive caster mimics the same effects as a negative camber when you turn the car. A wheel with a positive caster will tilt in as you turn and remain more perpendicular to the road, without the downsides of having excessive camber.

You see, as the car goes into a turn, the angle of the tire to the road changes, and the contact patch gets smaller. Negative camber increases the amount of tire touching the road when you corner, and that increased surface area makes a car stick to the corner better.

However, if you have a lot of negative camber, your tires will wear down much more quickly. By having positive caster, you will actually have better tire wear because you’ll be flat when going straight and when in the corners.

How Caster Affects Highway Driving​

Positive caster keeps a car more stable when going in a straight line for the same reason it returns to center after a corner. If we go back to the shopping car analogy, you can easily visualize the reason. As you push the cart forward, it wants to travel in a straight line and resists turning because the wheels want to remain aligned with the direction of the force.

However, there’s another benefit to positive caster. By making the steering input less sensitive and therefore harder to turn the car, you smooth out your ride.

Reduced Sensitivity to Road Conditions​

It might seem like a bad thing to have to turn the steering wheel more to get the car to turn, but the truth is that it’s actually a lot more comfortable. Roads are not perfectly smooth. They have a lot of bumps and imperfections, and each imperfection knocks the wheel around. If the steering input was very sensitive, that would translate directly to your wrists and jerk the steering wheel around.

Instead, with a positive caster, the steering system can absorb all those road imperfections without moving the car around. On a long stretch of highway, that means you don’t have to make constant corrections to stay on the road.

How Caster Affects Tire Wear​

Caster does not change the rate of tire wear as much as camber or toe. However, there is an issue that can occur if the caster is too far out of adjustment or uneven. The issue is called feathering, and although it’s not as common as other wear issues, it can cause some discomfort on the road.

Feathering​

Feathering can make a tire look like it has gills. When you look across the top of the tread, it should be even; all the tread blocks should be the same height. When a tire experiences excessive feathering, the tread will look jagged. This website has pictures of various types of tire wear if you would like to see it.

The biggest problem with feathering is that it can harm a tire’s ability to expel water. It’s certainly not the worst thing that can happen to a tire, but you will need to replace them sooner than a tire without feathering.

When to Adjust Caster​

There are two main ways to know it’s time to adjust the caster. The first is the simplest; your service schedule will have recommended intervals for checking and adjusting your alignment. Your caster will be adjusted to spec every time you have an alignment done.

The second way to know it’s time to adjust caster is when you notice your car misbehaving. If you have some excessive wandering on the highway or have trouble straightening out after a corner, you may want to have your caster checked. Generally, your other alignment adjustments will need servicing long before the caster, so it’s unlikely that you’ll notice caster wear exclusively.

Maximize Your Handling With Positivity​

Being positive is more than just a mindset. It’s a great way to keep your car stable and fast through the corners. Caster may not be the first thing you think of when you think of tire alignment, but next time you pick out a shopping cart, pay attention to how the front wheels behave. An erratic cart can ruin your day; don’t let your car behave the same way.

 

[1 Wild R/T]

Couple examples...
2018 Mustang GT from the factory 7.5 degrees of caster, earlier cars don't have quite as much, you might think Ford has a reason to crank up the caster number....
1977 Mercedes S class from the factory 12 degrees of caster... As a young auto tech even though I didn't think much of Mercedes I noticed when those cars turn you can literally see the tire lay over due to the amount of caster.... Like them or not Mercedes knows a little about making cars that are meant to be driven...

 

[biomedtechguy]

Well, today's the day!
I passed along the numbers that were given by the first several posters. I told him that I need it not to wander and not to follow the ruts in the road, and that it will see some drag strip use, but that isn't its primary purpose.
I also told him I got the SPC UCAs in part because he was one of a couple of mechanics that said the factory UCAs don't allow enough (or easy) adjustment. He agreed and thanked me for that.
I know there are offset bushings that help the factory UCAs "do better" but I'm good with the decisions I've made.

 

[biomedtechguy]

I want to add another THANK YOU to all who replied and participated in this thread so far, especially those who offered suggestions and information on the numbers they used or got for their alignment

 

[nativefx]

Something does not sound right. To be clear you also have aftermarket adjustable strut rods? Unless you have something bent what was done does not sound right. Now you need to start all over. For what its worth you do not need more than 4 degrees of caster.

Yup, something ain't right, likely a bent spindle or lower control arm an yeah 4-5 degrees is plenty... Hell the are plenty of Mopars running around with 2.5-3 that drive great...

Pnora, yes I have adjustable strut rods which I am assuming are Qa1. I had the entire front end rebuilt using the Bergman Autocraft complete front suspension upgrade BAC MOPAR A,B and E STREET FRONT SUSPENSION KIT - Bergman Auto Craft. We also upgraded to the Borgeson steering box. Just for reference, I had a 400/470 stroker motor built and we installed a tkx 5 speed while waiting on the motor build and the reason for the upgraded suspension parts. So everything is new.

The alignment specs provided were given to my by Peter based on my conversation with him about what I wanted as far as handling and driving style. I'm also running a 275/40/18 front tire and 295/35/19 rear. We had it aligned previously after everything was initially installed, but after driving I needed to make some adjustments and raised it slightly while also swapping the torsion bars around as they were labelled incorrectly from the factory, which is why I had to take for realignment but here locally in Bend rather than back to Portland. I did not have any tire rub initially and the strut bars from what I remember did not have any marks from a pipe wrench previously, which is why I called back to the shop and asked if the made adjustment only to the upper arms or also the strut rods. They confirmed that they had adjusted the strut rods to get me the specs I wanted (which they should not have done).

This alignment shop is not your typical 69.99 tire shop (typically 125.00-150.00) and I've used them with great success on my lifted trucks and lowered cars (modern). The old man that used to own it retired a couple years ago and he had a wealth of knowledge that he was trying to pass down to the people who bought him out, but I don't think they have as much experience with older cars.

PS - The strut rods are more than a 1/2" difference in length as it sits now an one tire is foward (rubbing) and the other might be slightly rear of center and does not rub. The difference in space between tire and lower front fender from one side to the other is almost 3/4". I'm going to start by resetting the strut rods and releasing any tension and bind to see where both side locate, but I don't believe we had a problem initially and they set the strut rods evenly, closely based on the factory length after the suspension installation.