Seering Wheel Shaking On Highway, Any Ideas?

[datrat240]

So.. I have this problem as the title states, On the highway (i.e. above 90kmh) I have a steering oscillation, feels like a wheel out of balance, not severe, but ANNOYING!

So far I have:

-Tried and re-balanced two sets of wheels

-Home string line, and shop laser alignment

-Replaced steering rack and tie rod ends with low k's(tight) 2nd hand items

-new polyeurethane rack bushes

-replaced upper and lower control arms with just jap adjustables (no rubber bushes)

-replaced castor rod with just jap rose jointed items

-HSD HR coilovers

And It still happens! I'm almost ready to drive the damn car into a tree!

It is a 93 R32 GTS-T, 170,000 kms, The wheels are 18x7.5 apec apache, with hub-centric rings, with toyo proxes-4 wrapped around them.

The car now handles fantastic, go kart like, with great steering feedback, but i still feel this "highway wobble"

I cannot feel any noticeable vibration through the chassis, only the steering wheel.

occasionaly the problem goes away for a minute or so, then comes back, so basically, I'm stumped!

Any Ideas? Please? I'll take any suggestions! I'm desperate!

[eeiko321]

ok

since your alignment has been done

the 2 most common problems that cause this symptoms are the Tires are out of balance, obviously the front.

(to test this....jack your car up......... rotate front wheels to the rear and viceversa)

if it stops...then just take it to a tyre shop and get a tyre balance done.

and another culprit could be a warped brake rotor... this happens usually with people whom wash thier cars after driving, hosing the hot rotors with cold water.

the logic of this, is that when it is warped...it is uneven... causing the rotor to rub on the brake caliper/pads.... causing an annoying vibration on your steering.

anyhow.......

1.) rotate the wheels

2.) while its off, inspect the rotor to see if its warped.

[datrat240]

Thanks for the prompt reply!

I forgot to mention in the original post that I have also replaced the front discs and pads too, no difference, although they are cheaper (reliance slotted) discs, not OEM. So I guess that is a possibility, though i get no braking shudder or odd pedal feel, and no "brake pad push" so i am disinclined to chase that up just yet.

I might borrow a friend's wheels and give it a try, just in case both of my sets of wheels/tyres are ovoid or out of balance..

[blind_elk]

Have you checked wheel bearings?

[eeiko321]

well because they are slotted discs doesnt mean they wont or cant warp

even if it doesnt rub against the calliper... uneven spinning balance for the disc under high speeds causes wobble just like tires

anyhow lets eliminate the tyres first

[.:: GimpS-R34 ::.]

maybe the road is just shit.. re-tar the highway and see if that helps..

ps. maybe a stupid question but have you actually told the mech or tyre shop what the prob is? or did you just go in asking for specific things to be done. ie laser alignment?

[bozodos]

I used to have that problem on my VN, and the one and only thing which temporarily fixed it was getting a proper manual alignment by a steering specialist, as well as getting the wheels rebalanced. In the end I was suspecting a stuffed rack from where I hit a gutter being a dickhead when i first bought it, but I noticed you've already replaced yours.

Have you checked your wheels for uneven wear?

[910trx]

as mentioned above, try a different road

last weekend while down in the gold coast i freaked thinkin something was off balance in the rear

turned out to just be the morotway between brizzy and goldie

does it change with speed ie occurs strongest at one speed and fade?

is is there from the start and just gets more noticeable with speed?

[datrat240]

maybe the road is just shit.. re-tar the highway and see if that helps..

ps. maybe a stupid question but have you actually told the mech or tyre shop what the prob is? or did you just go in asking for specific things to be done. ie laser alignment?

The tyres seem to be wearing with no cupping or scalloping, however a little "camber wear" is evident. I just had the tyres swapped left to right on the rims and re-balanced at a tyre shop on sunday, If I spin the wheels by hand with the car on the hoist my rims appear to run true, and the tyres have no noticeable visual runout.

I've done thousands of kays with this problem on all kinds of different road surfaces and the wobble is there on all of them.

It does get more noticeable the faster I go, So say at 90 it is just noticeable, at 100 it has definitely set in, and at 110 is worse yet, and for the sake of curiosity I found out that it is worse again 150 (on my own private racetrack of course! ).

About a month ago was my trip to pedders for a 28pt check and instructions to look for possible causes of wobble, I was informed that my rack, rod ends, lca bushes and ball joint were sloppy and likely they all contributed, hence I replaced them all.

My last alignment (castor, and toe front and rear) was done manually by yours truly, so could be a contributor, I'll get it professionally done in a week or so (including camber) to try to eliminate it as a cause (though I can't imagine alignment CAUSING a wobble, only aggravating it)

The discs appear not to be warped, however I guess they could be out of dynamic balance, does anyone know if/where I can get them checked for this?

I'll also try having a different tyre shop balance my wheels, It's worth a shot ey?

Failing all of that I will borrow a friend's wheels and give them a go. After that, i'm clueless!

Actually I did notice that the rubber steering column coupler is fairly floppy, but all of the other ones i've seen are the same, maybe I should just put one of those solid ally ones in to be sure? at least they're cheap!

Thanks for the replies so far, I'll take it all on board and update the thread as i get nearer to a solution.

[jus skott]

I used to have that problem on my VN, and the one and only thing which temporarily fixed it was getting a proper manual alignment by a steering specialist, as well as getting the wheels rebalanced. In the end I was suspecting a stuffed rack from where I hit a gutter being a dickhead when i first bought it, but I noticed you've already replaced yours.

Have you checked your wheels for uneven wear?

Sounds like you bent a rim to me. Here in the US we have shit roads. so bent rims is a sad and common thing.

~skott b

Edited April 21, 2009 by jus skott

[bozodos]

Funnily enough, I checked the rim and it was ok, that problem was also eliminated by driving around with stock rims on the front for a while to see if there was any noticeable difference. I have seen the same thing done and the rim damaged like you mention though.

[jus skott]

Funnily enough, I checked the rim and it was ok, that problem was also eliminated by driving around with stock rims on the front for a while to see if there was any noticeable difference. I have seen the same thing done and the rim damaged like you mention though.

hmmm the only other thing i can think of is to look over the car really good. look for any signs of chassis damage from hitting the gutter. like you have seemed to cover everything else.

[bozodos]

Yeah I was mentioning a previous car I'd owned, mentioning to the OP how I'd had a similar problem with a shaking steering wheel which was almost definitely a hairline crack in the steering rack itself. (also kept having to change rack boots). I no longer own this car thankfully.

[racegtst]

As you hav covered everything else,

maybe when you back out the drive you should get out and make sure the neighbours cat is removed from the wheels.