72 RR alignment specs needed

[cjanicke]

Does anyone have alignment specs for a 72 RR? I am sure the shop has the settings, but I didn't know if there is any adjustment to improve the car's handling.

 

[wvmarv]

Man. steering, caster= desired -5/8, limits -1 5/16 to +1/16. Camber= desired left +1/2, right +1/4, limits left +1/8 to +7/8, right -1/8 to +5/8. Toe in 1/8.

Power steering, caster= desired +5/8, limits -1/16 to +1 5/6. Camber= same as Man steering. Toe in same as Man. steering

Are you having handling problems?

 

[cjanicke]

No, I just wanted to get the most up to date specs given the use of radials and poly susp bushings. I didn't know if we should still use the data from 1972 as the best set up. Thank you for your help.

 

[dgraver]

Thanks I could use this info as well! The inside tread of my front tires are worn to the belt, while the rest of the tire is like brand new. Alignment/camber definitely off, hopefully I dont need to replace anything major.

 

[wvmarv]

No, I just wanted to get the most up to date specs given the use of radials and poly susp bushings. I didn't know if we should still use the data from 1972 as the best set up. Thank you for your help.

Yes, use original specs. no matter what tire your running.

 

[djais1801]

does that go for 71's as well?

 

[wvmarv]

does that go for 71's as well?

71 is slightly different.
Man. steer. Caster= desired -1/2, limits 0 to -1. Camber= left desired +1/2, limits +1/4 to +3/4. Right desired +1/4, limits 0 to +1/2. Toe in 1/8.

Power steer. Caster= desired +3/4, limits +1/4 to +1 1/4. Camber= same as Man. steer. Toe in = same as Man. steer.

 

[72RoadrunnerGTX]

Yes, use original specs. no matter what tire your running.

Can you elaborate on your response to this question please? The OP inquired about more up to date alignment specs for these cars running more up to date components as I understood the question. The 40 year old factory specs are far from performance oriented.

A quick check of the 71&72’ FSMs show the same factory specs for both years and “all” models. From the 72' Factory Service Manual, 71' FSM shows the same specs.

 

[wvmarv]

The specs I quoted were directly from a 1973 Motor's Auto Repair Manual. The chart you posted doesn't say what year. Since I was doing front suspension and alignment work from the bias ply tire through the implementation of the radial tire. I know from experience that the specs are the same no matter what tire you are running. I also know from experience that on caster and camber anywhere inside limits was good and would not cause tire wear or road wonder as long as you had the same setting on both sides. As far as toe in goes you better get it as close to 1/8 inch in as you could because very little variance will cause inner or outter tread wear. Too much in causes outter tread wear, too much out causes inner tread wear. As far as what you show here, whats your bitch. looks to me like the factory just didn't go into as much detail as what one of the best, if not the best motor manuals ever printed did. And the steering geometry of these cars didn't change just because the parts got better. As far as I know with more than 20 years in the business and performing alignments on thousands of cars the specs have never changed.

 

[72RoadrunnerGTX]

“What’s my bitch?” really? No bitch, simply requesting clarification on your advice to use the original specs on a question about more performance oriented alignment specs for these specific cars. Agreed, tire type not a really a huge factor, but there are ways to alter the non-tire wearing specs to improve handling and “road feel” without any other adverse effects. With factory suspension components however there will be limitations as to how far outside the factory specs, if at all, you can go. In my dealership experience (almost 40 years now) aligning countless numbers of these cars back then, achieving even the factory specs could be a challenge sometimes and compromises had to be made. For the less experienced, basically, get as much positive caster as you can evenly, side to side, that the desired camber will allow. Today, there are aftermarket parts like (adjustable or fixed with built in additional positive caster) upper control arms and/or adjustable LCA struts are available for this specific purpose. Offset UCA bushings are also available for use with factory UCAs.

More Info here

Running about 3 degrees positive caster and ¼ degree negative camber on this one.

 

[wvmarv]

As I said, the geometry on the front end hasn't changed. So the specs are the same. The after market parts of which you speak are used, as you say, when for some reason you can't get your settings inside the spec limits. I have never in my experience used those parts. When a vehicle was that far out of spec. we would determine if any suspension parts were bent and if none were found, put it on a frame machine to get it back into the spec limits. Then back to the alignment rack for fine tuning. I was looking at the picture you posted. Thats just a tubular upper control arm, made to the same specs as an original. The only difference is it's not stamped out of a flat piece of steel. It even uses an original type ball joint. Why would you need any other spec. for that? By your reasoning cars with sway bars would have a different spec. than cars without a swaybar. One more time. If you don't change the steering geometry of the vehicle, you don't need to change the specification.

 

[72RoadrunnerGTX]

As I said, the geometry on the front end hasn't changed. So the specs are the same. The after market parts of which you speak are used, as you say, when for some reason you can't get your settings inside the spec limits. I have never in my experience used those parts. When a vehicle was that far out of spec. we would determine if any suspension parts were bent and if none were found, put it on a frame machine to get it back into the spec limits. Then back to the alignment rack for fine tuning. I was looking at the picture you posted. Thats just a tubular upper control arm, made to the same specs as an original. The only difference is it's not stamped out of a flat piece of steel. It even uses an original type ball joint. Why would you need any other spec. for that? By your reasoning cars with sway bars would have a different spec. than cars without a swaybar. One more time. If you don't change the steering geometry of the vehicle, you don't need to change the specification.

Clearly you are a bit out of touch with the advancements that have taken place over the years on this subject. Take another look at the Mopar Action article linked above and or the additional links at the bottom of this post. Fact is, the particular upper control arms pictured above is not tubular in construction and was not built to same specs as the original stamped UCAs. Like most other aftermarket UCAs on the market today, most of them being tubular in construction, besides the other advantages over the stamped steel factory UCAs, the upper ball joint is located slightly aft of the original specs to provide additional caster for improved stability over the 45+year old factory design. Not to correct for the inability to achieve factory specs using factory parts for whatever reason.
I’m not following your reference to the use of anti-sway bars and their relation suspension geometry, of which there isn’t any relation. Did I say something about anti-sway bars?

Here is some more reading material;

Mopar Action article

http://www.firmfeel.com/tubuca_b.htm

http://waywardgarage.com/208/updating-mopar-suspension-on-a-joe-dirt-budget/

http://www.p-s-t.com/s.nl/it.A/id.7113/.f?sc=12

Again, the OP of this tread inquired about 1; the factory alignment specs for a 72’ Road Runner and 2; were there any “adjustments to improve the car's handling”

 

[wvmarv]

My bad, as I read the article it said an increase in caster would lead to better driving stability. I would agree with that, but I can adjust the caster on a car at +3 degrees or +1 degree and I bet you won't feel the difference. Setting these cars at the original specs is fine, were not driving them 20,000 miles a year and as long as 1. it goes straight down the highway and doesn't pull. 2. It doesn't wear the tires. 3. it doesn't wander all over the road. That will probably be good enough for the 99% of us that just want to go cruising on the weekend. I quoted the specs I had and my own experience. If you want to read more than that into it go ahead. I was just trying to help out. Take it or leave it, I DON'T REALLY CARE. My Road Runner is set at the prefered specs I quoted. And I'm perfectly happy with it. If your looking for alignment nervana, thats your problem keep searching grasshopper and some day you may find it. peace out

 

[72RoadrunnerGTX]

As you may know, along with the more positive caster, and better stability, comes more steering effort, hence the more negative factory caster specs for manual steering cars. Careful, you might lose that bet, the increased steering effort, sometimes referred to as “road feel”, is sufficient to be very noticeable for most, even with the typical Mopar over-assisted power steering.
My search ended long ago, for now I seek enlightenment for my fellow Mopar brethren oh Master Po, peace to you.

 

[cjanicke]

The information from the Mopar Action article is what I was looking for. Thank you for everyone's input. I have manual steering, but I think I will aim for the high speed stability and higher turning effort. As an extra benefit, I can tell my wife that I need to take the car for a drive for exercise. I may need to drive it 3 times a week for at least 30 minutes.


As a side note, it snowed here and I have to wait to drive the car over to the alignment shop.