69427

I'm interested in doing some changes in the rear roll steer (mainly reducing it) over the winter, and am trying to round up some parts. It's easier to buy the different length links/tubes if done in SAE thread, so I'm looking for some tie-rod ends with SAE threads that are "interchangeable", that is, will plug into the tapered holes in the rear knuckle arms. (Doing it in metric is my second choice as I would have to find metric tubes or buy additional LH thread metric taps, and LH tie-rod ends.) So, while I'm doing my search through suspension websites looking at hundreds of parts specs, I was curious if anyone here has already done a similar modification. I'm trying to keep a somewhat stock look, hence my preference for tie-rod ends versus heim joints.

Thanks,
Mike

Rob31

How much toe change are you getting ?

Crepitus

69427

I don't have it quantified yet. I still need to get a second dial indicator to do the measuring setup. I just don't like how the rear suspension feels in turns. The suspension is under my '69, and while the original C3 suspension used to always feel like the rear was going to pass the front on the outside of a corner, this C4 suspension feels like the rear wants to pass the front on the inside of the corner. It just feels like it needs a little less toe-in on the outside tire. I'm thinking on making the custom inner bracket adjustable so that I can change the pivot point and toe arm length in varying steps to get to the final geometry, rather than just jumping to a set length that looks good on paper or because of some measurements in the garage.
The fabrication of everything will be easy. The hard part so far is finding SAE threaded tie-rod ends that will fit the knuckle.

Rob31

Not sure what you mean by outside or inside of a corner ?
Do you mean entry and exit ?

My car does not like to be trail braked in fast corners . Loose on entry .
C4s like a little Toe in the rear
I did at one time have the inner braket (camber rod) moved down . This slowed down the camber gain , but it was horrible to drive . I was at the track and changed it back immeadiately .Stock location was much better .Changes Same day at Autobahn CC
I should have driven it a few more times. I wonder how much of that was cold track /tires .
On the street it wont be so noticeable .
Do you have early of late rear spindles ?
Id like to hear what kind of toe changes you find . Set he car at ride height with the spring out when you measure .

69427

C3s are prone to snap oversteer in corners due to the stock rear geometry allowing the loaded outside tire to toe out. When this happens, the rear of the car quickly swings around to the outside of the corner, passing the front of the car.
The SOTP feel with the C4 setup gives me the impression of the car trying to dog-track through the corners, with the rear of the car aiming itself towards the apex in an attempt to get there before the front tires do. It just seems a touch less rollsteer toe-in will allow the car to track a bit straighter through the corner and get rid of the dogtracking feeling.

Sidney004

How much toe in do you presently have with your current alignment, I assume all the bushings are new?

BrianCunningham

I have adjusters on mine, but they're rodend style

69427

Can you adjust the geometry, or just the toe-in?

wanabgts

I was planning on making a plate and measuring mine with a couple dial indicators as well. I think the rear roll centers are a big problem on the c4, but should be able to be corrected easily.

If i get a plate drilled ill post up my specs.

Zack

Rob31

Sometimes I wish the C4 just had a straight axle with long trailing arms .
Everything on my car is new/tight . I run 1/16 -1/8 toe in .
I ran 5/16 th for a session just to see ...stable but it was hard on tires .
My car hates being trail braked .Im thinking its a spring /shock issue more than geometry .
Im starting from scratch again , hope to make Gingerman 4/27

69427 , I have never delt with anything like what you said about the rear heading for the apex .
btw I did get a chainsaw for x-mas

69427

Excellent!

69427

It's been a couple years since I installed (and aligned) the suspension. IIRC, I set the toe-in to a minimal level (about an eighth inch), but it's certainly worthwhile to go back and recheck it. The bushings aren't new, but they're in good shape.

I'm making some ride height changes over the winter, so necessarily I'll have to make sure the suspension settings are back to square one.

Kubs

If you are tracking the car and still have bushings in the rear you are going to get a lot of geometry change and it wont be correct no matter where it is set. I know you said you wanted to stay away from heim joints, but they help a ton.

Here is a picture of my car on old Hoosiers (old = 5+ years and not very stickey) with the stock suspension. I started with -1° camber and the top of the tire is now in + camber:



This is after I installed the Banski kit (control arm and trailing arm slop will make the car do funny things too, not just the toe rods):



Another section to look in to if you really dont want heim joints is the inner toe rod assembly. It is just plastic in there and when I took my stock ones apart they were in several pieces and destroyed. Felt fine by hand when they were still on the car though.

shakedown067

Ah, that's good to know. I was just checking mine last weekend and they looked/felt good.