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Discussion Starter #1
For the last couple of years I have had a high speed vibration i have been unable to solve.

It appears to be coming from the passanger side front. It is noticable around 80mph, and gets worse the faster you go.

I have two sets of rims/tires.

My daily setup is a set of 18s with hubcentric adaptors. My "drag' setup is the stock 17'' rims. The car is on stock suspension, and has TRD motor mounts (stock trans mount). The car is a 6spd.

I am running Brembo Slotted rotors w/ hawk pads. Last year we put a runout dial caliper on them, and found the rotor to be warped. I had it machined, but I continued to have the vibration. This year I replaced the rotors, and the vibration still persists.

I have had the 18's checked no less than 3 times, and I am told they are fine, and in balance. This is the second set of tires I have had on them. The vibration is slightly less with the 17s, but I think this is due to a thicker side wall. I have also swapped the hubcentric adaptors from the "good" side with no change.

Today I put the car up, and checked to see if the wheel bearing showed any signs of being bad, but I cannot detect any play. Also it makes no noise.

Visual inspection and I can see nothing bent/misaligned in the suspension. The endlink on the sway bar has a slight bit of forward movement when pulling on it, but I would think this is normal.

Any suggestions is much appriciated.

TIA
 

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does the steering wheel shimmy at all? if not you have atleast eliminated dynamic imbalance of the tires, they could still be statically imbalanced, however you say you have tried all different tire combos with no luck? hmm, rotors are new and checked for runout, cant be that... you checked bearings and said there is no play so bearings and all suspension parts sound good. i guess i couldnt help you much over the keyboard.
 

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Discussion Starter #3
SupraDupaFlyBoy said:
does the steering wheel shimmy at all? if not you have atleast eliminated dynamic imbalance of the tires, they could still be statically imbalanced, however you say you have tried all different tire combos with no luck? hmm, rotors are new and checked for runout, cant be that... you checked bearings and said there is no play so bearings and all suspension parts sound good. i guess i couldnt help you much over the keyboard.

Yes, there is some steering wheel movement. I am getting pretty stumped. I'm not sure what else there is left to check. As I said, I have tried two different set of rims, and two sets of tires on the 18s. Same result.
 

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Are your front tires cupped on both sets of wheels? have you ever rotated them from side to side (dismount from each rim)?

This may be the issue.

DP
 

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Discussion Starter #5
Suprafied said:
Are your front tires cupped on both sets of wheels? have you ever rotated them from side to side (dismount from each rim)?

This may be the issue.

DP

The new tires have less than 2000 miles on them, and are directional. You cannot rotate them from side to side.

What would be the best way to check for cupping? Also normally cupping causes road noise. I do not notice additional road noise at lower speeds.
 

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Hwilli said:
The new tires have less than 2000 miles on them, and are directional. You cannot rotate them from side to side.

.
hence why he said dismount from the rim, go to a tire place and get them to swap the 2 front tires, off the rims, that way you can swap sides and still have the tread pattern going the right way
 

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Howard,

Most directionals you can rotate. You must dismount the tire from each rim and swap them and remount the tire to the rim.

Only very few tires are just a "right" and "left" only tires. My pirellis are like this. What kind of tires are they?

DP
 

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Discussion Starter #9
Well I certainly could do that, but since it does it on two different sets of rims, and a total of 3 sets of tires have been tested (2 on the 18s, and 1 on the 17s), I don't see what that test will show.
 

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If the vibration is in your seat its a tire balance issue. These go away at different speeds.

If the vibration is in the steering wheel, it's an alignment issue.

Have you checked your wheels/tires for road-force? A wheel and tire can balance out to zero, but they can still be out of round. The one thing I would check before I spent money on alignment is to make sure your wheels are still round.

Once this has been eliminated as the cause, check your alignment.

Also check TSRM regarding master or slave cylinders and make sure yours had it done. Early Supras had too long of brake cylinder caused premature wear on brake pads.

Regards,
James R
 

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Discussion Starter #11
James,

How do I check my wheels/tires for road force? As I said, the issue is the same between two sets of rims, and 3 sets of tires.

I am going to have the car realigned again this month after I put a set of coilovers on it. This as happening before it was aligned last as well though. Which has led me to try and find other causes.
 

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Road force - Usually the tire balance machine will have a road force equipment to test it. It is basically a roller that comes down and applies a certain amount of pressure on the tire to determine if it has excessive road force due to wheels out of round, excessive material in one part of the tire, failure of the belts within the tire.

Check here for more info a similar the machine:

In the middle of the page it shows how they check for rim measurement.

Regards,
James R
 

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Supra GTR said:
If the vibration is in your seat its a tire balance issue. These go away at different speeds.

If the vibration is in the steering wheel, it's an alignment issue.


Regards,
James R
Not entirely true. An out of ballance or excessive runout with cause a steering wheel shake. Getting an alignment will NOT cure a vibration. You are right in that the shaking from ballance usually comes and goes at different speeds.
If it is a low speed shake (under 40mph) is is usually tire runout problem.
If it is only at high speeds it is a ballance problem.

The hunter Road force variation ballancer will detect an excessive runout problem and From match ballancing it will tell the operator the optimal location of the tire and wheel assy. This machine does come in handy for tire guys that dont have that much experience solving vibration issues.

What exact speed does it start shaking?
Does it shake the steering wheel or whole car, or both?

Lawrence
 

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I had a similiar vibration feedback coming from my steering wheel. It started at a lower speed of 40 then get worse from there. The problem ended up being that I was missing one of the bolts on the most rear part of the drivestaft. Make sure they are all there and that they are all tight.
Good Luck
 

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Alignments if not correct can in fact cause vibration. They can also obviously, if corrected, fix it. Go to the tundrasolution forum and look up alignments the hunter engineer explains this thoroughly.
Alot of Tundra had vibes right out of the factory that his alignment specs cured.

I'd say road force balance-lance alignment.

http://www.redwoodgeneral.com/balance.htm

http://www.tundrasolutions.com/foru...-follow-up-on-alignment/?highlight=alignments

You might have to join the forum , not sure. But DJ worked for hunter as an engineer knows his shit and does consulting for them now, iirc. (retired)
 

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kaosv1 said:
Alignments if not correct can in fact cause vibration. They can also obviously, if corrected, fix it. Go to the tundrasolution forum and look up alignments the hunter engineer explains this thoroughly.
Alot of Tundra had vibes right out of the factory that his alignment specs cured.

I'd say road force balance-lance alignment.

http://www.redwoodgeneral.com/balance.htm

http://www.tundrasolutions.com/foru...-follow-up-on-alignment/?highlight=alignments

You might have to join the forum , not sure. But DJ worked for hunter as an engineer knows his shit and does consulting for them now, iirc. (retired)
Thanks for the reply, I guess you learn something every day. It just so happens that I have not had a shake cured by alignment in the over 2,000 alignments I've done so far. I will check into the Tundra vibration thing as I frequently lift and align them.

Lawrence
 
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