Shimmy won't go away

[Larry N. Johnson]

The front wheels (or wheel) shimmy at around 50 mph.
At 60 mph, it is gone.
At 40 mph, it is not so noticeable.
http://www.primequip.net/images/65%20427%20SC/Salt_Oct_07-014.jpg

Here is what has been done so far:

1. Replaced front tires.
1.5 Balanced front tires.
2. Turned the rotors; replaced the brake pads.
3. Replaced front struts.

Still shimmys.

This is abnormal behavior for one of the best riding sedans in the world.

What am I missing??

Any hints appreciated.

[Trout]

Have you checked the drive shaft?

[Marshall]

Have you checked the rear wheels. The same thing happen to a friend of mine and his father (I am the father's age, but the son graduated high school with my daughter) at Road Atlanta last year in their Porsche 997 twin turbo. They chased front end solutions all day even had the Kinetics race mechanics look at it. Rolled the rears to the Bridgestone tent, and the one of the rear wheels was way out of balance, but it felt like a shimmy in the front.

[Philip]

The front wheels (or wheel) shimmy at around 50 mph.
At 60 mph, it is gone.
At 40 mph, it is not so noticeable.
http://www.primequip.net/images/65%20427%20SC/Salt_Oct_07-014.jpg

Here is what has been done so far:

1. Replaced front tires.
1.5 Balanced front tires.
2. Turned the rotors; replaced the brake pads.
3. Replaced front struts.

Still shimmys.

This is abnormal behavior for one of the best riding sedans in the world.

What am I missing??

Any hints appreciated.


FCABs

[GCR]

Support arm bushings cracked or soft will cause this. So will excessive tire/rim runout or imperfect wheel balance. Too much toe can aggravate the problem too. Are your guys familiar with BMW's? Just noticed the wheels. Are they hubcentric?

[Mitch]

Thanks for your reply Alan!

[SOUTHERNBIMMER]

Tie rods, ball joints...lots of possibilities.

[Larry N. Johnson]

Support arm bushings cracked or soft will cause this. So will excessive tire/rim runout or imperfect wheel balance. Too much toe can aggravate the problem too. Are your guys familiar with BMW's? Just noticed the wheels. Are they hubcentric?

Good idea, thanks.

The 17" Fitipaldi rims are hub-centric.

I have the stock 16's. Maybe swap them on for a test.

All ideas 0welcome.

[Marshall]

Best advice...head to Grand Tursimo East and have them look at it. tell them Marshall and Danny sent you...well maybe not the last part.

[Larry N. Johnson]

Marshall,
Where is Grand Tursimo East ?
Larry

[EnderM3]

My guess would be bent wheel.

But yes Grand Turismo East is the shiz. they are in chamblee 770-455-0347. Call them and they will make it right.

[Mitch]

Speaking of hubcentric.....when I put the Style 66 wheels on my old E34 540i6, one of the hubcentric rings was crushed when the wheels were installed. I had a terrible shimmy from 45-60mph. Had no clue until Gran Tourismo found the problem and indexed the wheels, problem solved!

[Larry N. Johnson]

OK, lots of things to chase down. Thanks for all the ideas!

[SOUTHERNBIMMER]

OK, lots of things to chase down. Thanks for all the ideas!


Your not the only one Larry. I have a shimmy in my daily d and it's driving me nuts. I just came back from balancing the tires and it's still there. Thing is though is that I know I'm do for a full suspension update.:no:

[88e28]

Best advice...head to Grand Tursimo East and have them look at it. tell them Marshall and Danny sent you...well maybe not the last part.

Marshall, Not everyone is from GA. He's from FL.

[Marshall]

Details Details...Look for a bent rear wheel. I would call GTE and ask them for a shop rec in Larry's town.

[Carma]

yup
Best advice...head to Grand Tursimo East and have them look at it. tell them Marshall and Danny sent you...well maybe not the last part.

[DerekNitroRC]

speaking of a shimmy, my car is actually having one as well
so far I have replaced:
wheels
tires
control arms
put in urethane bushings
new tie rods
new struts
new rotors

yet I still have a vibration, so it is possible my driveshaft could be causing this?