Jackfit

Hi , I am almost ready to give an update on the rear suspension project.


Tomorrow I bring in the car for alignment. I have all the factory specs, but I know that the front with radial tires is set a little differently then factory.


My car is completely stock front suspension with original style A arms.


1966 L-79 with stock power steering setup. Tires are 215 R 70 15

Should I try to get for the following specs based on radial tires and my hi speed (70-90 mph) for long periods of driving on my
trips...



Front


Toe Factory ?
Caster As much as possible 2 + ? if A arm will allow
Camber Factory ?

Rear


Camber 0 or fraction less
Toe Factory




Thanks
Jack

Donald #31176

From the Duke Williams & John Hinckley recommendation for radial tires.
Touring = normal driving
Sporting= aggressive driving on winding roads



Default Re: Alignment Question
C2/C3 NOMINAL TARGET ALIGNMENT SETTINGS

Touring w/ radial tires
Front:
0 deg. camber
+1.5 deg caster (+2.0 w/pwr steering)
1/32" toe-in per wheel

Rear
-0.5 deg. rear camber
1/32" toe-in per wheel

Sport w/radial tires
Front:
as much negative camber as can be achieved up to -1.0 deg.
maximum positive caster that can be achieved
1/32" toe-in per wheel

Rear
-1.0 deg. rear camber
1/32" toe-in per wheel

Jackfit

Hi , I have taken the car in to a alignment shop to get an idea of what the present front alignment specs are ( I did not do any work on front) and to set the camber on the rear after the installation new strut rods and cam bolt kits and all bushings.

I did not bring any shims this time as I felt that they could do the rear camber without much c-2 corvette experience, plus I wanted to run the specs past the forum members for suggestions.

I have attached two photos of my left and front A-arms. Do I have any room left for shims to get the + 2 in castor on the front.?



This is how my car sits now. 1966 L-79 Convertible stock with power steering.

Left Front Right Front

Camber 0.1 + -0.1

Castor +1.1 +1.1

Toe +0.26 +0.26

Total Toe 0.52

Steer Ahead 0.00


Left Rear Right Rear

Camber -0.4 -0.5

Toe +0.5 -0.16

Total Toe +0.33

Thrust Angle+0.33

Pass Side Picture Fender on right side of picture



Driver Side Picture

TCracingCA

Will worthlessly chime in, but because you just kind of cruise and travel down the highways exploring and just cruising, do you really need to set it up for general best all around?? NO

I would therefore just set it up with more straight up camber, more castor though, and no toe!!!!!! This is in consideration to how I perceive it's usage from your super cool Road Odyssey and Jackfit Tales and Adventures on the Road saga!

Jackfit

Hi, thanks for the advice . My problem is , ( looking at pictures) Do I have enough bolt left to get to or as close to 2 degrees on the castor.

Which side or both do you add shims or take away. I want to know that so when the young alignment guy tries to get to spec , I know he is doing it right.....

Thanks

Jack

TCracingCA

yes because those a-arms are kinda of not perfectly triangular and perpendicular to the suspension, yes changes of castor do change camber. You are on the right path in seeing if even an inexperienced guy can get more castor based on the "as built" limits of the car chassis and how many shims will physically fit with proper nut engagement and naturally your camber!

i have slotted and subsequently plugged my C3 crossshafts with the Global west stuff, for my castor gain. and then i have the SPC arms (actually pole position because they are that old) on the C2 with their tall ball joints! So I am Apples to Oranges!

i haven't played with true stock a-arms in awhile, but now I am curious to go review the camber/castor ranges with them there stock parts (upper limits and negative).

I just hope the alignment guy isn't a son of some of the by-the-book Corvette forum members and appreciates the experience of working out a custom alignment where he isn't restricted to the corporate way of thinking like some kind of blind following clone! Make sure he is free thinking and a creative type of guy and not some employee by the spec manual robot programmed to the normal lousy service. But honestly if you can find even a guy that can get you in the general overhaul specs accurately, then that is a rare find, especially for the rear end stuff! if when they get to the back and there is a sudden long term stare down of the task (psyching himself up for what lays ahead), then just get your car out of there!

heck go crazy and jam a bunch of positive castor gaining shims to see how many will fit on the bolts, but do step back and look where you are at within your wheelwheels and your turn radius and the camber!

Which is better Apples or oranges, for future conversations???

TCracingCA

back when i thought you needed some magician or guru to do this stuff and i had a Camaro parked in the Guldstrand shop getting double adjusts and stuff, in my formative and development years of growing up-- I was ""that Customer" that actually suggested to Dick to simply put the alignment specs for the various intended usages into his actual catalog! It was a moment of clarity that hit me, to make such a simple obvious observation and suggestion, that he as a smart man with a fine engineering type mind ""smiled and patted my back"" and they ended up there in future catalog editions of his! One of many of my finest Corvette/Camaro related moments! The Camaro was getting dialed in for Mulholland Drive fun after I was embarred off of the hill when I had air jackers on the A$$.

Well 2 to 3 castor was and is a race recommended range setting, back in the day to the way of some modern thinkers in the cuurrent! Because more castor is highly recommended, because in race cars-- they tend to travel straight also at much higher speeds and so castor adds to the stability of traveling alot faster! But progressive modern thinking individuals are seeing the benefit of castor gains for even non race cars and even more than 3 pos for race cars! Naturally tight turning slalom cars will dial the castor back shortening the wheelbase to like 1 pos! and Grand Touring on our C2's is normally 1-1/2 to 2-1/2! If you are racing tracks, you probably should push that out to at least 3 pos minimum, depending on the track!

Ps plus most of you power steering types have power steering, so why not dial in more castor because it shouldn't be that hard in consideration of the cush accessory assist to turn the car and to parallel park it. I think minimum castor thoughts and settings had more to do with the poor weak armed guys that had to parallel park a Corvette more so than from any other factor!

BD104X

FWIW, I had a Corvette-literate alignment shop do my '64 (driver with modern tires). I asked him to shoot for +2.5 on the caster, after it was done he said the best he could do without throwing the camber out of spec was +1.9. My car drives & handles fine.

TCracingCA

He might have not had any of the fine thinner adjustment shims. Some shops only got big fat ones or a limited selection and adding one more of what they got, might have pushed you out of the range of your car chassis! And 1.9 should drive fine.

I was just trying to help with ultimate long range tire wear etc. since it isn't a race car!

Jackfit

I would like to thank all of you for your comments. Based on those and the other forum posts, I will have the shop try to do this.


Front

Camber 0 * LF and RT
Castor + 1.1 now try to get to 1.5 or more
Toe 1/31 " Degrees ?


Rear

Camber - .5 Both sides
Toe 1/32 " in Degrees ?

I will bring shims. The real problem will be Castor, Do I have room for shims on one side and only one shim to remove on the other . The car handles well , I just want I little more castor as indicated for power steering. I am not changing the arms .....

Pass Side Picture Fender on right side of picture


Driver Side Picture

TCracingCA

And I should clarify that I drive my cars with the steering wheel, but some toe helps the steering return to straight, so my racing zero toe or negative rear toe, wasn't appropriate to suggest in my opener, because I actually am used to re-steering the car back to the straight position or some semblance of straight, instead of it wandering back on line itself! Gives me kind of a Go-Kart feel and I am getting a double workout steering into the turn and steering out of the turn. I do have to keep reminding myself as to where you guys mostly operate your cars (streets)! Sorry I did ran-a-muck a little there on advice!

And I don't have any fancy power steering either, so the toe let's you look all cool-- one handing it on those stylish u-turns!

Jackfit

This young German Girl liked my alignment !

TCracingCA

If not, then at least you have a final picture memory of it and her as she was driving away!

Looks like she will be a fan now for life. You know what they say, "Once you go Corvette, you never go back!"

Jackfit

[I]Hey, I just realized that your description of driving is exactly how my car handles now and for the last few decades. You have to steer it. It goes very straight until you turn the wheel and yes, you have to turn it back, and if I get more caster, it will turn back by its self? Just like a modern car....oh boy...lol


Well the shims are on the way....should know final readings next week...this all started with a stripped oil plug on my transmission....

Have fun

Jack

TCracingCA

main focus, but you are getting the idea. It is surprising but a lot of guys think this is all common knowledge that everyone knows (toe, camber, castor), but factually many struggle with it and see it as some magical art for medicine men.

But I hate to break it to you, more Castor usually makes it harder to steer! It lengthens the wheelbase and therefore the car wants to keep going straight. The added more castor is a benefit to stability, and on these stock Corvettes because of power steering, tire rigidity, inflation rates, etc. you can increase it so the car doesn't jump back and forth in it's own lane so much or it will just seem to love traveling down the freeway.

See the real point in my posts is that the alignment should be tailored to the drivers style of driving. An alignment should be customized to your personal feel. And not to some general book spec.

The camber assists the turn and the tires road adhesion. The front suspension arcs and travel movements as you turn the wheel, that inherent turning of the wheel and the camber change arcs aid in steering the car. But I am trying to keep this simple, but Camber and toe can be killers to tire wear. And camber can affect stability greatly side to side and for straight. And then camber and castor setting can effect toe affect and reaction from setting the toe.

Toe helps to center the car hopefully to where you aim the darn thing and then helps it self return to straight. It helps you recover from the camber change from turning. It helps your straight line stability, so the car can itself thru toe search for a continiuous straight. But then toe can make it difficult to turn from straight.

If having to steer your car back onto line is not to your liking when returning to a straight transition, hopefully the little I have shared to help can help you in fine tuning what someone is doing related to the settings to suit your feel. And definitely so you can drive out of the shop knowing if you are good. Essentially the toe in causes the car to constantly try to search on it's own for straight. Too much causes it to try to do so while you are actually trying to turn, and too little causes not enough inherent assist to get back onto a straight line. So those little 1/8 increments are very critical.

I just would like to help you (a really good guy), get something that you enjoy. And I hate to say it, but that might be the exact factory recommended specs. Because if you think about things, they settled on those settings to please the masses of customers. And I personally think most are happy and content. But the conditions of the roads, or where you plan to drive it to and from can cause you to consider some tweeks to get the desired feel. If you have those heavy grooves cut into your freeway and the car feel like it wants to track in those and is pulling in directions causing you to fight the wheel, then the adding of castor would be worth considering. If you commute is through a winding road, then some added camber might be your cup of tea. If you are turning left and right at each stop light and the car has to center following those lefts and rights then toe might be a focus.

Etc.

This is a three dimensional puzzle and because of the roads, and road quality, road grades, road banking, road crowns, road imperfections, road feel to the wheel, you will never find perfection and none of the race cars do either (well on a controlled road like a race track possibly), but each setting could affect the effect on the other components and so it under all circumstances would never be perfect. But you want a car to handle properly or well to the majority portion mostly of what your planned usage is.

TCracingCA

I probably just confused a lot of people again.

Therefore if anyone else thinks they can clean up on my ultimate ability to convert head knowledge to a description that is not overly technical (which was what I just attempted to avoid) be my guest. The books on this subject are usually overly technical or to the extreme too simple in description to avoid confusion. And I haven't see the How to Align Cars for Dummies book, from the How to for Dummies series released yet.

What I do on my own cars has been successful, but then I have both simplified and complicated things with the racing parts.
Simplified based on less defection and give in components, less travel, etc. that makes hitting the alignment easier. More complicated because of all of the heim sphericals and the swivel and capability of movement and the added adjustability available like having on my race cars rear toe adjust without difficult to work with shims and rear castor adjust!

I jumped into the ASK Tadge thing, but this subject can be difficult to explain. The largest benefit in the modern has been tire improvements and road holding adhesion! So many flaws in a stock suspension with a design flaw can be masked somewhat.