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Very wobbly at high speeds


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That's the first place to check is worn out bushings. Could be anything really. Bearing, bushing, tie rod end, wheel out of balance. You'll just have to check each piece. No real way of just making a hazard guess of what it is.

Personally I had a bit of a shimmy in the steering wheel at speed that was caused by worn strut rod bushings.

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Ball joints and tie rod ends are the first culprits to check. Then bushings. Bushings are a pretty big job if you get a "master kit", search here and you'll find lots of tips that will save you time and effort, especially in the rear control arms area. Hint: spindle pin puller.

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I just bought a '73 240Z with tokico shocks and eibach springs but whenever I get onto the freeway and exceed about 60 mph, the ride gets reaaaally wobbly and twitchy.

Is there anything besides worn out bushings that could cause this?

Yep, lack of front spoiler will cause this.

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The first things I'd check would be the wheels/ tires, followed by front end alignment.

Only the toe is adjustable, but if it's out ie. 0 to negative it will cause the car to wonder/hunt. This can be even worse with wide tires.

These is also the possibility that a strut is damaged/bent or other damage to the front end has been done - throwing off other alignment settings...

If you have a good front end alignment shop - they will check the condition of the front end parts when they do the alignment. Alignment can not be made correctly with worn parts...

FWIW,

Carl B.

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Thanks Carl, you confirmed my first thought which was wheels/tires. When I got my classic car insurance and they limited my driving to 3000 miles a year I went out and bought cheap new tires. Immediately the car seemed to have a mind of its own (like he says, wobbly and twitchy). When the guy mentioned that he just bought the car, the thought ran through my mind that the PO put new tires to make the car easier to sell.

Misturmoneybags never answered my first question so I never posted this logical jump (my other initial thought was tires out of balance which is why I asked for further clarification of the symptoms), but it would be interesting to know if his Z has new tires, and if so, what.

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my z did the same thing but only at slower speeds. i have a front air dam, new ball joints, tie rods, eibachs and tokicos. everything in the front end is new with urethane bushings, but the steering wheel still shimmied. even had the wheels checked and rechecked. only when i went to a 15" konig wheel and new tires did the shimmy stop. now it's as smmoth as silk.

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Sorry for the late reply.

260zCaliCar -- yeah, the car does feel as if its trying to turn and I constantly battle with the steering. The tires may be the problem as well, because the PO mentioned that he had put on some new tires.

Thanks for your help everyone! I'll be taking the car to a shop specializing in Z's, so hopefully they can pinpoint the problem

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Sometimes the wheel can be out of round and not caught by the tire balancing. I had this problem with a front wheel for 31 years, always had a shimmy at around 45 to 50 and would go away after that. I kept the wheel and moved it to the back from the front and the shimmy when away.

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If you have checked the bushings and what the others have mentioned. You may have a wheel/tire problem. I bought a set of 15'' mags from a friend of mine and they had 225/50X15s mounted . Falkin tires and they were is good shape. I put them on my 240 and it was all over the road when I was on the freeway. Here in northern Ore. people run studded tires in winter and they will groove the roadway. These tires would hunt for a track and were vary squirrelly . I had only bought the wheels not the tires, but decided against using either . I sold the wheels and gave him back his tires and went back to my original turbines. My car is solid at speed now. I do have and had when trying the wheels, new struts and Euro stage 1 springs+ I lowered the car all around. This made the biggest difference.

Gary

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We seem to have a common thread here. My specific symptom with these new tires is that the z wants to exaggerate my steering, as if it grabs the "rain grooves" in the freeway, then suddenly breaks loose of the groove. This didn't exist with my old tires, and now it does. I haven't tried putting the fronts on the back and vise-versa, but it's certainly an interesting idea.

Just out of curiosity, if you take the car out on a regular street (not the freeway), do you still have to battle the steering? My steering issues are much less on streets (I had assumed it was because there are no grooves in the streets)

Misturmoneybags, you would be doing a huge favor if you let us know the outcome of your visit to the mechanic.

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Wider tires will always be more prone to wander and hunt lines and grooves in the road and can be exagerated by specific tread patterns. The steering on my 2002 BMW 525i is very tight but I still feel this effect on grooved roads or lines in the pavement from repairs. As interesting as this is, it is not the same as a wobble.

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If the above don't work, I have two suggestions.

1) Get Gasoline with a lower ethanol content. You are using Too high a proof for the car to toe a straight line!;)

2) Quit testing after a Z club meeting at a BAR! maybe the "testing equipment is the source of the wobble!:finger:

Seriously,

Two suggestions from personal experience.

1) Verify the nuts at the top of you strut are tight, a wobbling shock absorber(gland nut and/or the strut shaft nut) can do this and so can a wobbling strut assy(3 nuts at the top of the strut towers)-it only happens at speed when the front end lift floats enough weight off the contact areas to let them slide around, and occasionally in spirited direction change when the friction of the contact patch is overcome by the forces of inertia.

2) Verify that the tires are actually round-After adding a front spoiler my car improved seriously, but still had this issue, I had the tires trued, and never had such great tracking and ride.

Will

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A little late here but I think Carl said it best. Check the bushings and alignment. Tires can accentuate what is going on but generally bushings and alignment will cause "tram-lining."

My RX8 is set at 0" toe both front and rear along with significant negative camber in front. It will "wander" a bit depending on the road surface and is "twitchy" at speed. Just the way I like it. :)

Will, thanks again for your help this past Feb. Tom is hoping to be on track soon at RA. I race in two weeks at Nashville and will be testing an entirely new suspension set up.

Paul

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RXsleeper, I think you hit the nail on the head. Your term "tramlining" did it. I googled the word and sure enough, it's a combination of tires and/or alignment. Given that both misturmoneybags and I live in Los Angeles, I found this comment on an Infinity board funny:

"The worst case I ever had was while living in LA - the tires I had installed had their tread grooves at EXACTLY the same width as the rain grooves that SoCal DOT placed in on the freeways. My car would track on those and my car would swerve back and forth in the lane. I got stopped for suspected DUI within a day. I took them back and replaced them with a different brand of tire."

Alignment was at the top of the list of other items that cause this. I suspect the reason I didn't see bushings as a potential source on the other boards is our cars are old enough for bushings to be a potential problem.

Personally, since my bushings only have a few thousand miles on them, and my tires are brand new... It's alignment time. I'll let you know what happens.

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Check your bearings and make sure they are set properly. 240Z's have to have the front bearings set just right, or you will experience a shimmy.

I think this is what's wrong with my car right now. I get a slight wobble left to right in my streering wheel when driving on the freeway. I had new rotors and pads put on a while ago and ever since then it has been happening. It may just be because of the rotors somehow warping, but I want to check out the bearings. How can I check to see if they are set right?

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I think this is what's wrong with my car right now. I get a slight wobble left to right in my streering wheel when driving on the freeway. I had new rotors and pads put on a while ago and ever since then it has been happening. It may just be because of the rotors somehow warping, but I want to check out the bearings. How can I check to see if they are set right?

I had this on my previous car and usually when it just pulls to one side, it is most likely alignment.

And I just came back from the Z shop to get a estimate for my rear drums but I asked the mechanic on duty about the wobbling at high speeds and he said that it could be possible that my suspension is set up with 0 toe in. He says that with 0 toe in the car just hunts for the grooves in the road, but he also mentioned that he believes it could be tie rods as well. He'll be doing a full car inspection by wednesday of next week, so I'll give you guys an update.

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Yep, lack of front spoiler will cause this.

Having had a car with a front spoiler and one without it doesn't make That much of a difference. Not saying it doesn't make any difference but just not that much.

My current Z was plenty stable at 105 with well balanced wheels this morning. With the old wheels on it it would get squiggly at 75. And I still should get it aligned sometime as I haven't done that since replacing the steering rack (which it wasn't any more stable at speed with the new one)

The spoiler did seem to add stability in windy conditions but again it wasn't a fix for other suspension problems.

Edited by ta240
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I think this is what's wrong with my car right now. I get a slight wobble left to right in my streering wheel when driving on the freeway. I had new rotors and pads put on a while ago and ever since then it has been happening. It may just be because of the rotors somehow warping, but I want to check out the bearings. How can I check to see if they are set right?

Grab the top of the tire and rock it in and out. If the bearings are loose you will feel it, and it may even clunk.

Marty

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