BS on changing tire alignment specs from stock.

[cap67]

My opinion for entertainment purposes only. My 67 RT with manual steering even if it had power steering. if you bought a new RT or GTX back in 1967 the car would handle better than most mid size cars back then. just think if they had radial tires and gas shocks handling would be a great deal better. fast forward today a lot of talk about changing alignment specs for better handling and changing parts and adding things for better handling but hurting the ride of the car and harder to steer with negative camber or positive caster. just putting my RT back to close to stock specs like camber from negative camber to near 0 camber the car rides a lot better not hitting the bumps as hard still handles very nice. I like my classic cars for the characteristics of what they were when I first started driving them. yes put on the radial tires and gas shocks but anything more If I want modern handling better gas mileage better brakes better AC more comfortable I will just hop in my new challenger.

Hi I'm sorry but I disagree. My 67 has carburetor still. No efi. But with that said I Love to Drive my Convertible. New disc brake swap, newer style m.c. front/rear sway bars, c body tierods & sleeveselec ing. Factory looking aluminum rad. Grant wood grain wheel. Kyb shocks & Just put in borgeson box. With that said All stock interior and body chrome. Please I'm Not here to say what's better or worse. Just my choice. More Safety & drive ability.

 

[Coelacanth]

This topic is a good read, thanks to all the contributors. I'll be going through this next spring. My '70 Charger had 195-75-14's on it when I bought it in 1986, and upgrading to 255-60-15's in the rear and 205-70-14's in the front made a very noticeable difference. I now have Cooper Cobra 275-60-15's on 9" rims for the rear, 235-60-15's on 8" rims for the front, planned for next spring. That alone will help even more, but I have the Moog offset bushings for the UCA's ready to install. At that point, I'll probably lower the front end at least an inch, then get an alignment. This could be considered Phase 1 of the handling mods as all of this is pretty affordable compared to the more radical, non-stock suspension upgrades.

Like Jamie from DDG says, these cars handle pretty good with the original torsion bar system, but some modern improvements make a big difference. I will probably consider fast-ratio Pitman & Idler arms for Phase 2, but that'll be a ways down the road.

 

[OldIron]

A lot of specs across the board went from 1/4 p caster to 3 p caster from the early 70s to late 70s. Probably as a result of radial tires?
But camber generally stayed at about 1/4 p. Probably because the new radial tires stayed relatively skinny?

I've come to the conclusion that fat tires need to be run flat on the ground. So, 0 to 1/4 n camber might be a thing to consider. But any p camber can cause rut following with fat tires, and maybe other negatives. Excess n camber can reduce kingpin inclination (about 7 degrees or its bent) induced recentering.

Too much p caster can allow the car to be blown around by the wind and follow bad crowns.

I'm having good success with 2 to 3 p caster and 1/4 p camber on all my A,B,C, and M Mopar's 1972 to 1987 with skinny 205/70 to 235/75 fifteen-inch tires.

But not on my 64 New Yorker with 255/60-15. It wants 0 (zero) camber and likes just 2 p caster.

The biggest Mopar problem is the reaction springs and reaction washers in the steering box. The ones that tell the centering valve on the top of the steering gearbox what to do.
Stiff springs call the power boost in early and reduce play at the steering wheel with a smooth boosted lead in to turning the tires. It happens almost undetected if everything's working right. And the car goes down the road straight and stable with no sawing on the steering wheel. And yes, it's the one finger steering presentation.

Soft reaction springs (crush factor) call for boost later, which imparts play (2 plus inches) at the steering wheel, and then requires inconsistently more effort at the steering wheel.
So, we go straight from lot of play to it gets stiff quick when it does start to turn the tires.

 

[Kern Dog]

A lot of specs across the board went from 1/4 p caster to 3 p caster from the early 70s to late 70s. Probably as a result of radial tires?
But camber generally stayed at about 1/4 p. Probably because the new radial tires stayed relatively skinny?

I've come to the conclusion that fat tires need to be run flat on the ground. So, 0 to 1/4 n camber might be a thing to consider. But any p camber can cause rut following with fat tires, and maybe other negatives. Excess n camber can reduce kingpin inclination (about 7 degrees or its bent) induced recentering.

Too much p caster can allow the car to be blown around by the wind and follow bad crowns.

Sorry, man....you are confused. NEW cars come with a LOT of caster and they are far more stable than our old stuff when aligned to original specs.
I run 8 degrees of caster and a full degree of negative camber in the red car and 6 degrees of caster and 3/4 degree of negative camber in the other one.

No, the cars don't follow ruts, they aren't blown around by the wind or any other such nonsense. They track straight and the tires don't wear irregularly. Your words seem like those from a factory engineer that knows theories but has never actually deviated from stock to know what really happens. Even Rick Ehrenberg, a man that is also a strong proponent of following most OEM guidelines, advised for alignment settings far different than stock:

Thanks for chiming in but positive camber and 0 caster went out of favor LONG ago.

 

[toolmanmike]

There is an alignment shop in town and the owner aligns cars at Indy every year. They align most of the old cars in town. They use their own alignment guidelines. They know what causes pull and tire wear. They no how to compensate for road crown. They know how much caster is needed. The shops that align to factory spec and turn the car loose regardless of how it drives, are not doing a proper alignment.

 

[j-c-c-62]

So I wonder, how many alignment shops test drive the vehicles pre or post?

 

[oldbee]

Post, my guy asked to test drive when he was done. I couldn’t say no especially after he came back with a big smile on his face.

 

[toolmanmike]

So I wonder, how many alignment shops test drive the vehicles pre or post?

Many of the young guys don't. I have seen it at shops I visited in the last 30 years of the tool business.

 

[j-c-c-62]

They don't know how to drive a stick?

 

[Rennkafer]

I've come to the conclusion that fat tires need to be run flat on the ground. So, 0 to 1/4 n camber might be a thing to consider. But any p camber can cause rut following with fat tires, and maybe other negatives. Excess n camber can reduce kingpin inclination (about 7 degrees or its bent) induced recentering.

No modern radial performance tires need to be "run flat" and especially not on older suspensions with limited camber gain. Also look into "camber thrust" on modern performance tires. Bias ply tires need far less camber.

 

[Black_Sheep]

The QA1 UCA’s I put on the GTX allowed almost 5 degrees of caster. I no longer have to herd it down the highway, making it much easier to drive at speed. With power steering there isn’t a noticeable increase in steering effort.

 

[old guys rule]

Jarring? Don't really know how much negative camber I had in mine but you could actually see it if you looked hard and can't see how negative camber could make a car be 'jarring'.....? Mine surprised me at the modifications at how well an old car could really be. I remember my first 'home alignment' I did and took it to a shop to see how is was. The tech said everything look pretty good except for the toe. Thought that was odd since setting toe isn't that difficult. Anyway, he 'corrected' it and charged me 25 bucks (years ago) and off I went. Man, that car felt like it wanted to fall over some bumps and dips. I checked the toe when I got home from my slow ride and found it to be more than 1/2" in!!! How do you do that on an alignment rack? Never took my older cars to an alignment shop again and this guy was recommended by several of my buds. Maybe he was looking for some beer money that day?

I agree with you on having too much caster but imo, the factory settings on Mopars can be improved on. Chassis jacking is definitively a thing and have seen it on some GM cars where people turned the steering wheel lock to lock while moving very slow. How much caster did those cars have in them!!? Anyways, thought it was strange the first time to see it.

Anyone have good specs for street handling on early B body? I

 

[RemCharger]

Anyone have good specs for street handling on early B body? I

All the same info applies.

 

[cudak888]

All the same info applies.

...and the modern alignment specs will continue to be repeated over and over again for the next 20 years - or at least until all the angry old curmudgeons holding onto their precious, factory bias-ply settings eventually join the same resting place where their alignment specs went to die 40 years ago.



-Kurt

 

[toolmanmike]

See post #13. Scott has sold and set up alignment equipment for decades and was a front end/ alignment tech at a dealer before that. The post is what he recommends. Camber / Castor

 

[RemCharger]

...and the modern alignment specs will continue to be repeated over and over again for the next 20 years - or at least until all the angry old curmudgeons holding onto their precious, factory bias-ply settings eventually join the same resting place where their alignment specs went to die 40 years ago.



-Kurt

I just go with what works best. 0 toe 0 camber max caster. Done deal.

 

[gtxrt]

no right or wrong it's like what shoe should you put on first your right or left shoe first. I say whatever you're happy with is good. the best part of this thread tells you how to get there and what the reactions of the adjustments you make should do with your handling of your classic car. yes I learned a great deal.

 

[cudak888]

no right or wrong it's like what shoe should you put on first your right or left shoe first. I say whatever you're happy with is good. the best part of this thread tells you how to get there and what the reactions of the adjustments you make should do with your handling of your classic car. yes I learned a great deal.

That attitude can put others on the road at risk.

Just saying.

But yes, this thread has good things to learn from it. Sadly, the people who don't already know what there is to learn here are going to have a difficult time weeding the good stuff from the BS.

-Kurt

 

[gtxrt]

That attitude can put others on the road at risk.

you're kidding right ? if my caster is not 5* positive am putting others at risk ? but if I text and talk on the phone, not pay attention, do drugs and drink and speed on a busy road I should be alright as long as my alignment is where you say is good ? or could it be that 4-door cars are less risky to other drivers.

 

[cudak888]

you're kidding right ? if my caster is not 5* positive am putting others at risk ? but if I text and talk on the phone, not pay attention, do drugs and drink and speed on a busy road I should be alright as long as my alignment is where you say is good ?

Come on, you know what I mean. There absolutely IS a "wrong" way to set up Mopar suspension - enough that it's so skittish that any lapse of concentration will put you in a ditch.

That's the type of alignment that my '69 Valiant had on it when I got it. The seller was "happy" with it that way. It was definitely that ditch car.

No disagreement on the rest.

-Kurt