Front end shimmy at speed Options

[VaccaRabite]

When I’m on the freeway I get a vibration through the steering wheel if I’m going over 70.
On surface roads everything is smooth sailing.

It’s probably a wheel that threw off its weight, but I can’t check that till Monday.

Bearing are new. Rotors are new.

What’s the checklist?

[rjames]

A lost wheel weight is a solid culprit.
How old are the tires? Maybe tread separation? Do you have a spare you could use to swap your wheels out one at time to rule them out?

Grab the wheels and check for play to ensure it's not a loose or bad bearing (or worn spindle), too.

[emerygt350]

When I’m on the freeway I get a vibration through the steering wheel if I’m going over 70.
On surface roads everything is smooth sailing.

It’s probably a wheel that threw off its weight, but I can’t check that till Monday.

Bearing are new. Rotors are new.

What’s the checklist?

I just went through that too except I had just put turbo tie rods on. Luckily I decided to have the weights checked, and sure enough, it had thrown a weight. I really need to learn to photograph the wheel...

[Cairo94507]

When I had my wheels balanced, I used black racers tape to cover the weights since the backs of the wheels are black. Never lost a weight yet. Also, on my car, deep sixes with 195x65x15 Michelin tires, I have found they are sensitive to tire pressure. If one of my tires get's 2 pounds low, I can feel a slight vibration. Air tires and smooth as glass again.

BTW, I run my tires at 28F and 31R. I have no idea if that is good or bad, but my cars rides great. (IMG:style_emoticons/default/beerchug.gif)

[emerygt350]

When I had my wheels balanced, I used black racers tape to cover the weights since the backs of the wheels are black. Never lost a weight yet. Also, on my car, deep sixes with 195x65x15 Michelin tires, I have found they are sensitive to tire pressure. If one of my tires get's 2 pounds low, I can feel a slight vibration. Air tires and smooth as glass again.

BTW, I run my tires at 28F and 31R. I have no idea if that is good or bad, but my cars rides great. (IMG:style_emoticons/default/beerchug.gif)

I was putting duct tape over mine. Seemed to work. When I was doing the high performance driving school at the Glen, the weights laying on the ground were knee deep in the green group paddock....

[VaccaRabite]

Update.
Car is on the lift.
Ball joints are tight and seals are intact. There is no wobble or play in the front end of either front wheel. Tie rods seem fine.
Cat hasn’t been aligned in about 4 years but it tracks straight.

Monday I’m calling to have the wheels balanced and I’m going to get the pressure dead nuts on all of them. I did not check pressure before yesterday’s drive. It was about 80 miles all told, but almost all of it was surface roads and country roads. Way too nice a day for the freeway.

On FB Bruce mentioned the rubber puck in the steering shaft. A possibility but I can’t fix it this weekend, and I’m driving the car next weekend so I can’t take apart the steering shaft to investigate.

Zach

[Steve]

I’m running Michelin 17” pilot sport tires. When they got close to the wear indicator they started vibrating really bad unless the road was super smooth. New tires solved the problem, but could of been a balance issue.

[Superhawk996]

When I’m on the freeway I get a vibration through the steering wheel if I’m going over 70.
On surface roads everything is smooth sailing

I don’t understand what this means.

So if you do 70 or over on a smooth road you don’t get vibration and shimmy? Is it distinctly related to something of freeways like expansion joints?

Let’s clarify terms:

Vibration can be in any direction X,Y or Z axis. It is usually random, non-cyclic, non periodic, continuous.

Shimmy is an oscillation of the steering wheel around its axis of rotation, or of the vehicle that is cyclic, side to side, front to rear, or a pulsation type feeling.

[tomeric914]

Are the front wheels hubcentric?

Are the rotors hubcentric?

[Spoke]

I don’t understand what this means.

I think he means around town at lower speeds.

I had the same vibration at high speeds last year. Both front wheels were a bit on the loose side wrt bearings. So I tightened up both sides and the vibration went away.

[nivekdodge]

the hub vs lug centric thing is real. If you search on Hunter's site or Coates you will see references to it. our cars are lug centric and the wheel must be fastened to the balance machine with the lugnuts.

Kevin

[SirAndy]

One more thing to consider is wheel spacers. Even just a thin one can throw off your balance.

Ask me how i know ...
(IMG:style_emoticons/default/rolleyes.gif)

[Superhawk996]

I don’t understand what this means.

I think he means around town at lower speeds.

I had the same vibration at high speeds last year. Both front wheels were a bit on the loose side wrt bearings. So I tightened up both sides and the vibration went away.

Ah . . .

The reason I was looking for clarification is that 70mph and above is an unusual speed for tire balance concerns to show up.

[VaccaRabite]

So the hub centric vs lug centric is interesting. And may be the issue. The last shop that mounted the tires last year balanced them through the hub, not the lugs.

Also, I cleaned the back of the wheel yesterday and took of over 12oz of wheel weights over 4 wheels. It was clear that as tires got changed the last shop never removed the old weight.

@Superhawk996
At slower speeds, the car drives fine. No shimmy in the steering wheel.
On a smooth road in 5th gear (so about 70ish) the steering wheel started oscillating. Slow it down, it goes away. On country roads in 4th at around 55mph the wheel is steady.

The car itself did not feel like it was shaking or vibrating. Engine sounded great. Trans not making unusual noises.

Wheels are 4 bolt fuchs, with 1 year old tires on them that still look brand new - maybe 1000 miles on them.

No wheel spacers.

Years ago I put on studs with the correct lug nuts instead of using lug bolts.

Turbo tie rods in great shape. Seals all intact. No play in the ball joints. No play on the hub. Front wheel bearings are new, and well greased. Rotors were replaced when I did brakes this spring, and I'm not getting any knocking noise that would indicate runout on the rotors. Also, the shimmy is independent of the brakes.

Zach

[Jamie]

One more thing to consider is wheel spacers. Even just a thin one can throw off your balance.

Ask me how i know ...
(IMG:style_emoticons/default/rolleyes.gif)

And me too! Aluminum 12mm spacers in the front were not hubcentric on first mount, I turned them on my wood lathe and was able to get rid of the wobble by carefully torquing the lugs when mounting. Just have to pay attention when centering with each remounting of the wheels now. (IMG:style_emoticons/default/bootyshake.gif)

[Superhawk996]

The last shop that mounted the tires last year balanced them through the hub, not the lugs.

Also, I cleaned the back of the wheel yesterday and took of over 12oz of wheel weights over 4 wheels. It was clear that as tires got changed the last shop never removed the old weight.

Wow! You’re on the right track. That’s an awful lot of weight on your wheels.

Good call to basically start over. Find a shop that will put the proper adapter on the machine to balance lug centric. They will all default to hub centric unless you force the issue.

In my experience the tire techs are terrible about saying they will do one thing but then the guy in the back does another out of ignorance. Hard to find good shops and even then you need to keep an eye on what they’re doing.

[euro911]

Have them run the bare wheels to see if they have a heavy spot and mark them. Then mount the tires and run again and mark the heavy spot on the tires.
Have them rotate the tires to offset the heavy spot opposite the heavy spot on the wheels. Should balance out, or use minimal weights to balance.