Can wheel spacers affect "balance"? E21 content...

I've got some 20mm spacers on the E21 that allow me to run the Miata 15x8s, but I've also got what seems to be a tire balancing problem.

Significant wobble/shaking at about 65ish, give or take.

Front end is all new with the exception of the control arms, which have less than a few thousand miles on them (though they've been on the car more than 15 years, the car was non-op for the vast majority of that time).

So, had the fronts balanced, still have wobble.

How likely is it that cheapo spacers are contributing to the wobble?  I didn't think they would, since they're at the hub, but, don't know.

I don't recall the ball joints feeling flimsy when I pulled it apart to put the coilovers on it, tie rods are new, new rack bushings, wheel bearings feel pretty tight (weensiest bit of play, though it might be a bit of rack play).

Thoughts?

I had hoped to get the car to auto-x weekend following this one.  Ugh.

They can if they're not flat.

You had the tires balanced, did you have the tires checked for runout?

Almost guarantee this is runout, I've had cheap spacers give me serious steering vibration before.

I have a vague, distant recollection that the E21 was known for developing a shimmy at 55-65 when the control arm bushings failed. It's worth at least putting a prybar on them to see how much movement there is. It's also a perfect place for a polyurethane replacement.

02Pilot said:

I have a vague, distant recollection that the E21 was known for developing a shimmy at 55-65 when the control arm bushings failed. It's worth at least putting a prybar on them to see how much movement there is. It's also a perfect place for a polyurethane replacement.

+1 on this.  I thought it was 45-55 but that may be with stock wheel/tire diameter vs. what you have on there now.  

Yeah, I'll third checking the bushings. You might see if you get a similar vibration from a hard braking at speed too. Also if the car has been sitting you might double check your tire pressures. Flat spotting in tires tends to be more noticeable at speed and more pronounced at lower pressures. 

In reply to 02Pilot :

They should be ok, oldish, but not used much.

pete, define runout, at the wheel, or tires themselves?  I.e. is the spacer causing runout, which was Angry Corvair's assessment?

I've had a similar problem with one of my Minis, happens at 48-52 mph with no or light load........I've done EVERYTHING new on the whole front end. I'm at my wits end, so I'm going to put a steering stabilizer on it like they do on Jeeps and see if that tames it.

Oh, and no spacers.......

Don't e21s need hubcentric wheels and spacers?

Margie

In reply to Marjorie Suddard :

I don't think so. I've got E21 rear brakes on my 2002, and IIRC there's no provision for a hubcentric wheel mounting. I've run non-hubcentric spacers on that car for decades without issue, albeit only 5mm ones.

Recently on our champcar I thought spacers caused issues with our tire wear issues. Come to find out it was the lower control arm bushings. 

Depending on how long it has been sitting, the tires may be flat-spotted.  If my M3 sits for a couple months it feels like crap until the tires get fully up to temp, like 15-20mi.  After a couple of heat cycles and/or with more frequent use, no problems.

Edit:  Found this...

"With E21 hubs the wheels must be hubcentric (center on the hub)! 57.1mm must be the center bore of the wheels.

If the center bore of the wheels is smaller, they will not fit. If the bore is larger than 57.1mm the wheels will always have a balance issue at highway speeds because they are not centered on the hub."

I also found a post on the 2002FAQ for people running E21 hubs that says that any spacer wider than 6mm must be hub centric.  Depending on the bore of the Miata wheels, they may not play well with a hub centric spacer.  I think the Miata center bore is 54.1mm.  IDK if there is a 57.1mm hub centric spacer that will reduce down to 54.1mm available?  

Both the E21 and Miata have a 60 degree taper on the bolts/nuts, so that should be ok.  

Bushings at the sway bar mounting, or the inner mounts at the subframe?

I'll check it all out, but not a lot of miles on the control arms.

Tyler H said:

Edit:  Found this...

"With E21 hubs the wheels must be hubcentric (center on the hub)! 57.1mm must be the center bore of the wheels.

Yeah, my E28 required hubcentric wheels, and when I switched later-model BMW wheels that were not, it exhibited the same symptoms the OP is describing until we mounted the new wheels with hubcentric rings.

edit: Do you still have your old wheels and tires? Could switch back and see if the problem is suspension or wheels/wheel spacers.

Margie

To answer the thread title....  not unless something is wrong.

Loose fasteners, foreign material between mating surfaces, bent fasteners, etc.

P.s.  this might be controversial...  I have never balanced my race tires and wheels and never had any vibrations.  Those vibrations are usually from mechanical looseness or the wheel / tire not being round in my experience.

Tyler H said:

Depending on how long it has been sitting, the tires may be flat-spotted.  If my M3 sits for a couple months it feels like crap until the tires get fully up to temp, like 15-20mi.  After a couple of heat cycles and/or with more frequent use, no problems.

Edit:  Found this...

"With E21 hubs the wheels must be hubcentric (center on the hub)! 57.1mm must be the center bore of the wheels.

If the center bore of the wheels is smaller, they will not fit. If the bore is larger than 57.1mm the wheels will always have a balance issue at highway speeds because they are not centered on the hub."

I also found a post on the 2002FAQ for people running E21 hubs that says that any spacer wider than 6mm must be hub centric.  Depending on the bore of the Miata wheels, they may not play well with a hub centric spacer.  I think the Miata center bore is 54.1mm.  IDK if there is a 57.1mm hub centric spacer that will reduce down to 54.1mm available?  

Both the E21 and Miata have a 60 degree taper on the bolts/nuts, so that should be ok.  

Wheels have something like 65mm hub bores, so larger than Miata or E21.

Spacers are hub centric, and stay "mounted" while I put a wheel on.  I couldn't see fighting the spacer while trying to mount the wheel.  Turns out more useful than I thought!

Car sat for a couple weeks, but 200tw tires seem a bit finicky, so, first step will be drive it a bit, then hub centering rings, and last resort, control arms and poly bushings to go with them.

Check lug nuts...

In reply to Marjorie Suddard :

I do, and that thought had crossed my mind as well.  Easy enough way to eliminate an item or two.

In reply to wvumtnbkr :

Yeah, torqued at 73ish ft lb, though E21 says something light like 56-65 or something like that.  I did 5-8lbs above recommend on it.

I think Miata wheel torque is 75-83 or something.

Short story long, I think they're tight enough.

Follow up on this, hub centering rings seem to have solved the problem. 

Had it up to 80mph or so, no issues. 

No other changes to anything, just the hub centering rings.

I had this exact problem on my E36 with the same solution. Glad it worked for you.