Snogard

So for all the people with the same wiggle problem, here is my story and solution;
I had notorious rear end wiggle since the beggining of owning my car. I tryed to swap from Michelin to Pirelli tyres (19 inch) and nothing changed. So i decided to check the rear axle alignment. It had very big tou-out setting. So we decided that we should try with almost zero toe-out and voila- no wiggle at all!!! It totally transformed the car. So my advice to everyone with rear end wiggle problems at WOT, try to do rear axle alignment and set it to zero toe or maybe just a liiiiiitle bit of toe-out. You will be suprised, beleave me

I am very , very happy that my killing wiggle is gone.... Hope that someone else will also be able to eliminate it with my method....

AMGPilot

Stock alignment is for toe-in, Toe out is NOT advisable

Snogard

I know that very well, and that exactly is the reason why we corrected mine pretty big toe out setting on rear axle (dont have a clue why it was set like this, but maybe all people have wiggle problems because of nonintentional big toe-out on rear axle like in my case??). Anyway, we decided to left just a liiiitle bit of toe out (which when in motion is a toe zero) to totaly eliminate rear end WOT wiggle. No negative effects of minimum toe out, just ful elimination of wiggle.

AMGPilot

Nope, Dynamic toe is always out never in. you have toe out in motion and that's not good

wsybert

Good explanation HERE. It's always a good idea to have a little toe in on the rear, as a baseline.

CynCarvin32

Try some high speed braking maneuvers and let us know how the car feels. Then try some high speed transitions and see how that feels. Taking out the toe in may help stability when launching the car but it will make it a hazardous car when at speed. The back end will end up being very unstable when you brake or transition the substantial weight of the E at speed.

If you have the rear end wiggle buy some toe links as the wiggle is caused by changes in toe under load with rubber bushings. Take out the rubber and things will feel much better.

splinter

Wiggle? If I’ve read Snogard’s post correctly, his car had a “very big toe-out” angle prior to adjustment. That’ll do it.

^ Sound advice from AMGPilot and CynCarvin32. Any dynamic rear toe-out can also manifest diabolical handling during high-load braking and transitional lateral maneuvers.
Deflection inevitably results in decreased toe during acceleration loading, thus the recommendation for upgraded toe links and/or stiffer bushings.

Note AMG specifies increased static toe settings on some of its chassis to better accommodate their altered ride height and additional thrust.

Snogard

As i already said; we made MINIMUM static toe out setting, basicaly toe-zero (in reality it IS totaly toe zero when in motion, because rear wheels at WOT (at our cars enormous torque) try to horizontaly "overtake the vehicle" in radius with zero point at wheel carier and at that moment we have toe zero even if staticaly is set at slightly toe-out). Anyway, i made 500 hard and mild kilometers since then and i can not feel ANY negative effects except no more damn wiggle. That is pure victory for me!!! And even if there wiil be some negative effect that i dont realize it wright now yet, i will GLADLY except it in exchange for no wiggle at all. But each to its own...


Btw.sorry for my bad englis, i am trying my best.

Snogard

...and have notorious rear end wiggle? Nope, but no thanks. Not for me anymore.

Snogard

That is correct. We dont know why it was set like this, but we corrected it to nearly toe zero (i beleave that when all 700 Nm push in, slight toe-out is EASILY turn intotoe-zero on our car. And i beleave THAT is the erason that all our cars with OEM rear axle setting have wiggle-because of too much toe-in when WOT-ing. But that is only my humble opinion...


Oh, and Btw. we have 3 mechanic shops in family and toe zero setting on rear axle with rear wheel drive is not that rare that you may think....Sometimes even customer itself demand toe zero setting from us....Especialy when sport car is in game...


It is good debate though....:-)

Snogard

That sentense only confirmed my statement that very slight static toe-out at our cars on rear axle comes into dynamic toe zero at WOT (and we are interested in WOT performance of alignment more then when in stady motion , doesnt we?).
And yes, i am aware od aftermarket toe links, but with my present setting i dont feel that i need them anymore. Only question that remaions for me now is tyre wear. And even if there WILL BE slightly more tyre wear, i will gladly exchange that negative effect for no wiggle at WOT

P.S. Front axle is different story. We need toe-in there because when we brake strong, wheels tend to toe-out, so in reality when we have static toe-in on front axle, at hard braking that toe-in becomes toe-zero or even toe-out. Thats how it works. Handling and steering is different matter....

AMGPilot

No Dynamic toe will NEVER be in due to castor trail and sidewall deflection, when rolling a tire will ALWAYS toe out.

Toe out is not the thing you want to have in any high horsepower rear drive car, the car will always walk to most loaded wheel under hard acceleration

Snogard

When rolling yes, when WOT-ing, no. Just look at the side of a rear wheel drive car when it is taking off the line with a lot of throttle..you will see how rear wheels tend to toe-in....And i strongly beleave that is the reason why our cars at OEM rear axle alignment setting makes wiggle. Too much torque on too mushy rubber bushings (tending to toe-in at WOT).
It is plane and simple phisic-because of rubber bushings our rear wheels ALWAYS tend to "overtake the vehicle" (but because they can obviously not do that, they toe-in at WOT so notorious wiggle begins.....).

Snogard

So why doesnt my car walk from side to side with slight static toe-out?? Maybe your car did it with slight toe-out setting (your first hand experience, like mine?)?

It seems that OEM aliognment setting makes our cars to walk from side to side, doesnt it?

As much as it sound weird and contradictory to all of us well known strictly recomended toe-in OEM settings on all 4 wheels, it obviously doesnt work on our cars on rear axle. Except if you dont mind to have wiggle......

splinter

No worries. :)
For clarification, MB’s W211 five-link aft suspension deflects toward toe-out during acceleration loading.

AMGPilot

Doesn't work that way, Toe in stabilizes, toe out destabilizes that's why it's a tuning tool when setting up a race car

AMGPilot

EXACTLY!

Snogard

I understand that it should work that way, but yet why does it shows contra on our cars (although my setting at rear axle is near toe-zero, so almost nothing toe-out (few degree seconds out at static)?
All in all, it seems that i have solved my WOT wiggle, and that is all that matters to me.
Maybe someone else with wiggle problem should try set rear axle to toe-zero and report..... So far i have found no ill efects of doing that, only total elimination of wiggle.

Snogard

As i understand, rear wheels on rear wheel drive car have tendency to toe-in while WOT-ing, not toe-out, and our 5 link suspension trying to eliminate that problem is obviously not working its job like its suposed to (look at the side of our car when someone in the cabin is trying to take off from standstill....You will clearly see rear wheels tendency to toe-in (try to "overtake" the vehicle body). So while motion at WOT it should be even worse....
Another proof for me that it doesnt work what it should (prevent toe-in at WOT) is wiggle problem.....

Interesting debate though. It seems to me that wiggle phenomen had not been researched enough.....So i think threads like that are welcome....

splinter

If that was the case in this specific instance, why would having decreased your former toe-out improved its straightaway WOT stability?

edit: merely for the sake of discussion - not trying to be a jerk.

Snogard

Good question, and also hat down to you because i see that you are indeed reading what i am writing So to answer you; I am guessing that most people here (if not all of them) with problems with wiggle have OEM alignment setting on rear axle (so toe-in according to AMG specs). And purely on that fact and on the fact that we have set my car to toe zero and totaly eliminate my wiggle problem i am speculating that toe in from default from the begining (and so much greater toe-in when WOT-ing) is the culprit for wiggle. We could go to another level higher and let my car be set back to OEM specs (toe-in) and will see what happens....I am And i am not 100% that i will not do that in the matter of 1 week just to confirm my theory and save a lot of people of wiggle headache...I just need to find spare time, because wright now i am pretty busy with other problems....


P.S. you are not a jerk M8, we are just having healthy discution And thats what the boards are for.

AMGPilot

You understand incorrectly, ALL tires on any axle try to toe-OUT under acceleration

Velociabstract

My car (R170 chassis) toes out under compression. I track the car and have set it from 1/8" toe in to 1/8" toe out and many settings in between. My car ...... and I prefer some toe in.

Les

Hotrod-Realtor

OP. According to your original post, you said "It had very big tou-out setting" and you changed it to zero / near zero toe and that corrected your wiggle. Most people agree a slight toe in, is preferred. Seems to me you almost have your toe set correctly and you realize that toe out causes wiggle. No?

CynCarvin32

Sometimes people do not want to realize the truth on a topic. On my track E36 bmw I listened to one associate and went with a zero rear toe setting and the car refused to go straight at speed. I moved my hands even the slightest motion and the car walked all over the place on the straights. In the corners I drove looking out the side windows as I could not keep it in line.

Back at my former toe settings with a slight bit of toe in and the car was back to normal. This car has no rubber bits deflecting so the setting were constant. A couple 32nds of toe made a huge difference in the controlability of the car. On the EVO X going with zero toe works up front and some even run a bit of toe out to create superior turn in. Out back it still has a bit of toe in but very little.

With the design of the MB 5 link, the e55 in question is going very toe out under load and that wont work well with high speed transitions. Sure it may be fine but when you need the suspension to control an emergency maneuver or blast through a freeway interchange the toe out condition will not be desirable.