front wheel shimmy

[alan6272]

I have the 1983 944 N/A manual steer. My issue, I have a steering wheel shake starting at 50mph and gets worse, I don't even dare go over 65mph. I have replaced both ball joints,inner tie rod, and both struts, the front end is tight and the alignment is perfect. Both front tires are BRAND new, wheels straight and I took them back to be rebalanced. Has any one had this?? I am racking my brain because I have checked and rechecked every thing.

[mikepellegrini]

Here's a thread with a possible answer. I have the same thing on my 83 but haven't tried the fix to see it it works: Street wheel alignment settings

My car, when you get it about 65 feels great. The shake is only at around 60.

Like you, I've replaced the struts, the ball joints, the control arm bushings and the tie rods - everything's new.

The only thing I haven't done are the wheel bearings, and that's coming soon.

[John_AZ]

+1 ^ Need slight toe in.

Was the alignment done at a Porsche shop--Independent or Dealer?

What brand of "new" tires do you use?

Some have luck with an "on car" balance if you can find one.

Many owners have a similiar problem.

Vibration at 60-80? Getting frustrated... - Rennlist Discussion Forums

GL
John

[AA_Ezra]

Outer tie rod? were did you mange to purchase just the inner? i had to but the whole thing inner plus outer.

Maybe the Steering shaft linkage. The topic has not come up much but back in the day that was the problem for most after replacing what would normally be the cause. and since they are no longer available people were getting the steering shaft linkage from the late cars and had a shop modify them ( shorter i think)

But yeah i guess an alignment shop is supposed to put 150lbs of weight on the driver's side. I weigh 210 so i guess either i bring my own dumbells or i sit in the car for 30 min while they align it?

[alan6272]

Thank you all for the input, I have cheaper new tires but this is just a DD, I think I am going to go with the alignment part and I will take it back for that with porsche's specs, it is an independent shop and I am sure they are not aware. I am glad that this is not just my car. I will keep you updated. Alan

[RedBaron]

These are the fixed alignment values mentioned in the PCA Tech article by George B.

WHEEL CAMBER
Front: -20' ± 15', maximum difference left to right 20'

TOE-IN
Toe: 1/16 inch toe in per side for a total of 1/8 inch toe in.

TOE ANGLE DIFFERENCE
at 20° to left and right -1° ± 20'

CASTER
2,5° + 30' - 15'

I set these on the manual rack on my S2 and it works very well. Also, are your wheels properly balanced?

[ernie9944]

Me think you got wheels/tires problems not alignement one.You migth have a wheel which isn't perfectly straight ,don't take much believe me. Early 944s with manual steering are very sensible & you must have straight & well balance wheels or they will get Parkinson decease quik.Ask the shop if they can balance the tires to the wheels (which I doudt) but this is the only way to eliminate the shimmy if one off the wheel is not straigth.But first check your wheels bearings all around & make everything is snug ,secondly tire pressure on an early 944 should be 29 psi/front no more than 34 psi /rear.If your running cheap tires this migth also be the issue one migth have a faults in it which is very hard to dedect.Balancing tires to the wheels is an art & not very many peoples can do it, for those who don't know how it's done I'll try to explain. What they do is separate the tire from the wheel then he turn the tire to a certain position on the rim ( lol hope you guys are following me) once done he does inflate the tire back then run it on his machine,the guy don't even look at the number on the machine but concentrate on the tire when it spin,if he detect a small wooble he will then start the procedure again until the machine is showing a perfectly balance wheel.Had the same shimmy between 50 & 60 mph on my 83 & that how we fix it.Not saying it's was cure 100% (using the tire to wheel balance method) but what about 95% which is good enougth.

[ernie9944]

Me think you got wheels/tires problems not alignement one.You migth have a wheel which isn't perfectly straight ,don't take much believe me. Early 944s with manual steering are very sensible & you must have straight & well balance wheels or they will get Parkinson decease quik.Ask the shop if they can balance the tires to the wheels (which I doudt) but this is the only way to eliminate the shimmy if one off the wheel is not straigth.But first check your wheels bearings all around & make everything is snug ,secondly tire pressure on an early 944 should be 29 psi/front no more than 34 psi /rear.If your running cheap tires this migth also be the issue one migth have a faults in it which is very hard to dedect.Balancing tires to the wheels is an art & not very many peoples can do it, for those who don't know how it's done I'll try to explain. What they do is separate the tire from the wheel then he turn the tire to a certain position on the rim ( lol hope you guys are following me) once done he does inflate the tire back then run it on his machine,the guy don't even look at the number on the machine but concentrate on the tire when it spin,if he detect a small wooble he will then start the procedure again until the machine is showing a perfectly balance wheel.Had the same shimmy between 50 & 60 mph on my 83 & that how we fix it.Not saying it's was cure 100% (using the tire to wheel balance method) but what about 95% which is good enougth.

[ernie9944]

OOPS!!!! that what I deserve for posting twice.

[alan6272]

I got the wheels back today and they said one was 1.5 oz out. I am going to have the alignment redone also. Thanx Again Alan