95carrera

Is alignment needed after adding spacers? Mine are only 5mm around 60 mph it gets bad shimmy. What se could it be?

badabing

It could be the spacers are not sitting flush on the hub or the wheels are not sitting flush on the spacers or both.

The slightest bit off at the center (we're talking thousandths of an inch) is magnified as it extends out towards the tread.

You need to make sure all the mating surfaces are clean of any rust, debris, burrs etc

Beyond that maybe get the wheels and tires match mounted and RoadForce balanced by a shop who has the GSP9700 machine and knows how to use it.

You want a dynamic balance with clip on weights on the inner plane and stick on weights on the outer plane (but still on the inside of the wheel). If you can't do clip ons on the inside than you'll have to do stick ons on both sides.

LimeyBoy

^^^ Second this. I had spacers on for months no issue - then the front wheels were taken off and replaced = bad shimmy at about 60mph. Removed everything, cleaned and all good again, must have been slightly off when re-installed - probably made worse because my spacers are cheap non-hub-centric.

aarrow

This.

And no, you don't need an alignment...unless you, for some odd reason, messed with your tie rods.

pcst

I don't recall having the alignment done after installing the spacers.
Did you get them brand new or used set?
The point I want to get to is, they shouldn't cause vibration as long as they are straight and installed flat while torqued equally on all bolts.

NP993

There was probably a burr or speck of dirt introduced to the mating surfaces during the install....remove, clean, reinstall, and shimmy will probably go away.

Quadcammer

Another generous RL member gave me a set of 5mm spacers to try out. I've heard they may help with turn in and reduce understeer on the front of my turbo.

Has anyone found this to be the case?

thanks

chsu74

Oliver,

I have only read that thinnest hubcentric spacers are RUF 7mm for our 993s but they are $$.

https://rennlist.com/forums/9693011-post22.html

ilko

I've ran spacers on my cars in the past with no problems. Even if they aren't hub-centric.

Increasing the front track will reduce understeer, but it won't be a night and day difference. Wider tires work better in my experience. If you have 225s go with 235s. That's what I have currently and the car handles very close to neutral even with 295s in the rear.

If you get 7mm spacers you'll need longer studs as well. 5mm is the most I'd use on my car with the stock studs.

Neil Perry

Hi
I made 6mm hubcentric spacers for by car, what a pain in the butt, it is possible to make hubcentric wheel spacers probably down to 3mm to 4mm with no issue. The fingers on the hub of a 993 are not solid, there are three fingers spaced, with gaps, which make it possible to make hubcentric spacers.
Photo attached

Another thing to check, is to tighten the wheel nuts in about 5 stages, each nut opposite the last, using a torgue wrench.

Quadcammer

i will have to check but i think i have 245s up front with 295s in back and my car pushes a bit even after playing with the swaybars. its not bad, but if theres a cheap easy way to dial it out more, im game
thanks for the input fellas

Steve Weiner-Rennsport Systems

Add some camber,...

Seriously tho, is it a low-speed push or a mid-to-high speed one??

95carrera

So i pulled the spacers off to inspect. Everything was clean underneath, no visible debris and these appear to be well made hub centric spacers. I drove about forty miles on them today before I did this, and it seemed to be getting worse the longer I drove. After they came off, the shimmy went away. Now I did torque the lug nuts after removing them so that could have been the problem. I am really not sure and would like to put them back on.

Unfortunately I realized that I had tore up the threads on one of my lug bolts when I put the wheel back on a few days ago. Cleaned up the threads by rethreading them with a die. It helped but they aren't 100%. Another example of my self-inflction of damage to this car. Not the first time I have done something stupid that damaged the car in the last couple of month.

Not sure how to proceed from here. The 5mm spacers helped the look but I don't want to pull the wheels again, mess with the partially stripped bolt, etc, only to have them shimmy again. Any suggestions besides "stop screwing up your own car!" ? Could the torquing alone soive this?

Ed Burdell

Does 5mm make a noticeable difference in the appearance? I've been toying with the idea for awhile now.

I thought 7mm were safe to use with the original lugs as well, but that is not the case?

Ed Hughes

Reading this, I deduce you did not torque the nuts when you had the spacers on? Why wouldn't you? Just because you have spacers, doesn't mean you don't follow lugnut tightening procedures. If I understand right, this is probably your issue.

Get your stud replaced, re-install the spacers and mount your wheels correctly, and see what you get.