I was finishing up the coil overs on the back last night and decided to carefully check camber change throughout the full suspension travel.
The car is sitting on jack stands and the shock is in but not the coil over spring. I am testing for full range of travel to make sure nothing hits or binds.
I put my caster/camber gage on the hub with the wheel hanging fully down, zeroed the gage then with a small jack compressed the suspension until it was totally compressed and checked the gage.
I had .5 degree negative camber. I tried it twice and got the same results so I know the camber is not changing through out the suspension travel.
Might not be a good thing but for me and my straight line high speed running I know the tires are staying planted on the ground.
You can't actually zero a camber gage, You have to mark the reading and subtract or add to that starting reading.
I will try for some accurate toe changes over the full travel this weekend.

 

Great work Norval!:) Why didn't GM have you on the design board a long time ago?

I sure wished that I would have had a 6 link years ago when the stock yoke wore off so short allowing the yoke housing by the half shafts to move in and eat away the Differential case.

Anybody with over 75,000 miles should pull the rear end cover and inspect how much the their yokes are worn. MY whole original diferential went in a dumpster at 50,000 miles because I didn't know that I had to check.

 

:lurk:

 

I know it's not possible with our suspension set up, but do we want our rear suspension to be a mirror image of our front (provided the front was corrected like what you have done)?

BTW- congrats on the 6 link. Eventhough the 6 link probably excells in the straights I imagine it is a great improvement over stock in the twisties.


[Modified by applevette, 6:17 PM 11/19/2003]

 

George I didn't design the 6 link. I got the articles posted here a few years ago , got the bug and built the system. I really like it and I am forever tinkering with settings and it really works for quick toe and camber changes.
Like you said it totally eliminates the need for good yokes. In fact I grind them off back to the clip.
I just don't see why others don't go that route.

Applevette do we want our rear suspension to be a mirror image of our front
What do you mean by this. Our rears are not like the front. I just hate the 1/2 shaft acting as a pivot point with the strut holding the wheel in place.
Since I have switched to coil overs it is even more important to run a 6 link. The coil holder is welded to the side of the trailing arm putting a twist on the trailing arm. The upper strut rod will stabalize the trailing arm more then any 1/2 shaft.
Take a 4 foot stick and hold it in the middle and ask someone to try and twist it out of your hands and even a weak female can do it. Now spread your hands wide apart and ask her to do it again and she doen't have a hope. Our stock rearends are almost this bad. The 1/2 shaft is one hand in the middle and the lower strut rod is only about 6 inches apart.

 

Norval, I know I"M on dial up, but could you please send me some lo count pixels of the rear setup you did there??? highly interested....

maybe some dimensions and material list for the parts....

thanks....

GENE

 

Norval-
I mean would we even want unequal length control arms out back, and if so, would we want it set up exactly like the front? I too hate the half shafts acting as a control arm.

 

Norval - The first time I ever saw the 6-link was right here on this forum. I think that the young guys name was Arron. I can't remember his handle, but he was a fellow Canadian of yours. Didn't he even give a manufactures name?

Why would you shorten the yokes? I don't see why it would be worth the bother.

 

Guys look at this http://www.corvettefaq.com/susp.asp It has lots of information of 6 links and chassie setup.
Aaron bought his system but all you need is 4 5/8 heim joints and a 10 inch connecting link that can be bought from Coleman racing for a few dollars. Other then that a stud welded to the crossmember and a little fabricating on the trailing arm and you are set. I could easily build it for under $100 .
The half shafts need to be shortened, this is a must because as the wheels move up and down controled by the strut rods the 1/2 shafts move in and out of the housing. Stock the wheel moves in an arc about the fixed 1/2 shaft. With the 6 link the wheel moves straight up and down and the 1/2 shaft moves in and out to accommadate the changing length.
If you lay under a car with a 6 link and no spring attached and move the wheel through it's range of travel you will see alot of movement in the 1/2 shaft as it slides in and out of the housing. If the yoke is too long it bumps into the cross pin causing severe binding.
Double click to enlarge

 

applevette maybe the 6 link is like control arms. It has a shorter top one, 13.5 inches center to center and a longer lower one. They act like our A arms. The trailing arm acts to hold the assembly from twisting.

 

Then are you still getting toe in upon compression?

 

I don't know yet about toe changes as I need to install a large aluminum plate in place of the wheel and install dial gages, then move the wheel through it's travel without the spring to determine toe changes. I will do this if not this weekend in the next week. That is the only way to really tell accurately.

 

Understandable.

In theory though, because the trailing arm does not pivot at any point in a line perpendicular from the inner pivots points doesn't it have to go toe in?

$#%^*!!! I need pictures. I can't explain myself at all!

 

Why can't the wheel just move up and down perpendicular to the ground and at the same time no pivot for toe in/out?
I don't know and until I get under there and start measuring and observing I don't know. I often spend hours laying under the car just studying how I could change things.
My shop is heavily rugged so it is nice laying on the floor, the car is usually a few feet in the air on stands so it is easy to crawl under.

 

ok, ok, I'll wait. :cry

 

Me neither. Had my setup on for 10Kmiles and 1-1/2 yrs now. Even if you're not into handling imrovements the maintenance and adjustment benefits are worth it IMHO. I just wish it came with poly ends instead of heim joints.

I put on rebuilt yokes from Bairs trying to tighten up the rear & fix poor handling prob's & 5000 miles later I had 1/8" slop on each side again. I swore if I tore out the diff again to fix it something different was going in its place.

I hate the OE design. I'll never go back. I can also tell a significant improvement in rear plant upon takeoff. Not good if you like burnouts though. :D

dr





[Modified by DavidR, 6:16 PM 11/19/2003]

 

Glad to see you like it DavidR. I love the easy adjustments of toe especially. I see no negative side to it.
The hardest part is tearing the rearend out .

 

Norval,

Looking at you photo of your 6-link (1st time I've seen your rear suspension actually...), I've got some questions, if you don't mind...

1.) What is the 2nd lower strut rod doing in the photo?
2.) Did you weld the inner mount for the upper strut rod to the X-member, or do you have a bracket bolted to the diff housing?
3.) I've seen the mods on your offset trailing arms for wider tires, but it looks like the rear of them (where the leaf spring bolt attaches) was moved inwards... for a shorter spring and tire clearance?
4.) The rear bearing assembly looks a little different. Is it something you've build yourself?
5.) Out of curiousity, do you have the diff X-member solidly mounted to your frame, or are you using the rubber vibration isolators?

I've always enjoyed reading your posts. Whether it be your killer garage/workshop, or the next round of tinkering on the car. Your work on your vette is quite inspiring.

Oh yes, I can't forget to give a hats off to the weight saving method employed on the tranny X-member... :cool:

 

1 The second lower strut rod is from the other side holding the wheel assembly up. I just pulled the pin for the outer strut rod and put another one in.

2 I don't believe in a bracket bolted to the housing. The housing bolts to the cross member and the bracket bolts to the housing. Why not simplify things and just weld a mounting stud to the crossmember and be done with it. No fancy bracket to make or bolt on. It was really easy designing a stud and welding it on. The key is knowing the correct alignment for this stud in relation to the 1/2 shaft and lower inner strut mounting point.

3 My trailing arms are knotched for wide tires, My frame becomes my limiting factor. The sping mounting bolts have been moved inboard for a shorter spring and increased tire clearance. Springs can be cut with a saw and drilled for new mounts. The stock spring would hit the inside of the tire.

4 The axles are hand made and 85% larger then stock. Besides bigger axles and much bigger splines the bearings in the housing are also much larger. It took very little effort to bore out the housing and install larger races.
Both the inner and outer flange are removable. I double splined it and can replace the axle flange with any bolt pattern


5 I am still using the rubber mounted cross member. I hate noise and rattles and worry about solid mounting the rearend.

6 Most of my parts go on a diet. Look at the front crossmember. The front lost about 39 pounds in total between holes and acid dipping.
double click to enlarge

 

I have always liked the 6 link idea because it eliminates most of the camber change through out the travel of the wheel. But I don't think it does anything to stop toe change during suspension travel, if you set the ride height with the links parallel to the ground as the outboard tire moves upward in a turn the links move the wheel closer to the center of the car while the front pivot point of the trailing arm stays the same. Thus the outside wheel toes out upon compression which is why in a hard corner the c2-3 has a tendency to get loose because the outside rear wheel is trying to drive the rear end by the front end.

I think it is why on the stock set up from gm the lower camber rod angles down from the center out to the trailing arm. That way when the outside wheel compresses in a turn the camber rod move the wheel out to create some toe in to keep the rear tucked in behind the front end. It seems like everything is a comprise if we continue to use the trailing arm arrangement.

Just my 2 cents worth.