weird vibe at 60

[3VPOWA]

BUMPING AN OLD THREAD

Did you ever resolve this issue?

I've had my my Pentars on for 3 years now. I recently had a new pair of Nitto 555 275/40/R18's put on to replace the worn out pair. Before I had these put on I never noticed a shimmy. I did run the tires/wheels I purchased from a member on here for about a week before I could get the tires on (noticed one of the tires was slightly taller than the others so i put them on the front --- they were the same size just different brands).

I had the tires on the rear replaced and moved up to the front. The ones on the front I moved to the rear; they only have 10,000 miles on them since I bought them new back in October.

I took it to one tire shop and they told me my ball joints were bad. Quoted me $500 to get them replaced. I said eff that and purchased FRPP GT500 front lower control arms and put them in last Friday. The steering feels tighter but I still have a shimmy.

I took the car today to the place I purchased the tires and had them rebalanced. Still have a shimmy. So I decided to move the new tires to the rear. Still have the shimmy.

It seems to happen throughout the whole range of speed. When I brake the steering wheel shakes as well. At times it seems worse than others.

I'm at a loss of what it could be. The car has 53,000 miles on it. Not lowered, factory supsension.

Suggestions would be greatly appreciated.

 

[stkjock]

Did u try to road force balance the tires? Is the shimmy in the steering wheel?

 

[Newman]

Warped rotor ... Mines done it for ever .

 

[3VPOWA]

Did u try to road force balance the tires? Is the shimmy in the steering wheel?

Yes, and yes.

Warped rotor ... Mines done it for ever .

I was looking at the driver side front rotor and it looks pretty scored. Will having a warped rotor cause a shimmy while moving?

 

[Newman]

Yes . I drove a customers car today like that.


I've been through 3 LF rotors. My caliper is messing each up .

 

[3VPOWA]

Yes . I drove a customers car today like that.


I've been through 3 LF rotors. My caliper is messing each up .

This is good to know. I was going to take this as my next step in trying to correct the problem.

Is it the caliper itself that is causing the rotor to warp? And if so, what exactly do you mean by that?

 

[Newman]

Not sure.... But my left front it's the only rotor I've replaced and I'm on my 3rd one. So my guess is a bad caliper. I have all new calipers and rotors in my garage waiting to go on .

 

[V8 Vol]

I've been chasing a vibration in the steering wheel as well. My issue is sometimes its there and sometimes its not. I have come to the conclusion there are hard spots in the tires (555's) that soften the more I drive since the shimmy tends to go away after a little driving.

The vibration would be quite violent when I first start driving and makes you think WTF, but eventually settles down.

Does this help? I dont know, but I thought I would throw it out there for anyone reading this thread.

 

[3VPOWA]

When I first got the tires put on it sounds similar, but since i've rotated them it can't be that. I drive roughly 100 miles/day and it does it pretty much all the time now.

I ordered two new OEM front rotors from Tousley and some Hawk HPS pads. We'll see if it's that scored rotor causing this.

Sent using Tapatalk

 

[kevinatfms]

mine ended up being my steering rack, i had every available tech and engineer that i worked with helping me try to figure out what was going on. from what i remember the pressure bleed valve(internal to the rack) has a small spring in it, well when i wrecked my car a few years ago it seems that this spring had either broken or compressed enough to allow excessive pressure bleed of the rack causing the rack damper to slowly bleed off resistance pressure.
i replaced the rack and no more issues. originally i thought it to be my gt500 struts but i changed them to tokicos and still did not change. i had to call a ford powertrain engineer for my district and we went step by step by step over a 3 week period to rule out parts and pieces. we finally did a pressure test and found the return pressure to be very low.

 

[3VPOWA]

mine ended up being my steering rack, i had every available tech and engineer that i worked with helping me try to figure out what was going on. from what i remember the pressure bleed valve(internal to the rack) has a small spring in it, well when i wrecked my car a few years ago it seems that this spring had either broken or compressed enough to allow excessive pressure bleed of the rack causing the rack damper to slowly bleed off resistance pressure.
i replaced the rack and no more issues. originally i thought it to be my gt500 struts but i changed them to tokicos and still did not change. i had to call a ford powertrain engineer for my district and we went step by step by step over a 3 week period to rule out parts and pieces. we finally did a pressure test and found the return pressure to be very low.

Wow. That's really interesting. If the changing the rotors out doesn't help, then I'll probably take it to the dealership and have them take a look at it.