Steering Wheel Shimmy

[David J]

I am suffering from steering wheel shimmy ( rather than shake) at around 60mph tyres have been balanced several times to ensure it is not a wheel balance issue, suspension and joints checked for play every thing appears to tight. Has anybody suffered from a similar issue and what did you do to fix it.

I should be gratefully for any ideas and pointers to find a solution to this problem.

David

[threep]

Tyre bulge?

[LM mic]

Could be on the shock absorber with a leak of pressure inside or something wrong inside that gives a "resonnance" vibration which field is in beetwenn 60 mph and over then stops in higher speed ?
you can check this in doing a test on safe place where you can go at 55 then go at 60 and if shimmy start just brake down hardly and let the car go then ; if the shimmy disapear that 's probably somme issue on front Chock-units
Hope this idea helps ?

[peteracs]

Hi David

Not in the same league as your tyres I know, but I had a similar issue with my old Chrysler Voyager, had endless balances, swapped wheels, checked brake disks for warping etc. In the end we changed the tyres (to another brand), instant resolution to the problem. Just an idea if you can swing in another pair of wheels just to try.

Peter

[john]

In the end we changed the tyres (to another brand), instant resolution to the problem.


Yes, we've experienced that, especially on tyres that have sat for lengthy periods without the weight taken off.
Don't know if this applies David, but worth a try.

[Darkspeed]

As above regarding shocker. Had the same thing on a Ginetta, turned out the shock had developed a dead band and offered no damping over about 5mm of piston movement.No other indications of any fault but steering vibration. Was a right pain to track down.

[David J]

Thank you for all for your responses, it gives some other areas to scrutinise in a bit more detail The tyres I have fitted are Falken 225x15x50 ZIEX ZE912. John and Peter you could be right in both your comments regarding the tyres , The car is parked for long periods during the winter just being moved occasionally, it could be that the tyres get a bit out of round. When I think on, in the past the steering shimmy seems to improve the more miles I put on the car. I am having a good run out to Ravenscar on Sunday so I will monitor how the steering performs.
Not sure how good Falken tyres are ?, I must admit they were keenly when I bought them.

The shockers are AVO coil overs fitted a couple of years ago.

Many thanks
David

[Sando]

Another vote from me on the cold tyres that have been sat on for a while. It should go once they get thoroughly warm though.
Other things to think of - slight play in wheel bearing(s)- easily sorted with a little nip up.
also if the tracking or caster is a little uneven you may get the wheels fighting each other. If the front tie bar bushes are worn you can easily get toe out once moving at speed and this will give some instability for the rest of the set up to deal with.
also check lower steering column UJ as first signs of this going is that little bit of play in the steering.

If it is tyres, can you swap the wheels over from side to side? or turn 180deg on each hub? see if it makes a difference.
Rob

[ChrisCar6]

I'm getting a bad vibration through the steering at 70-80 mph. Will need to check all of the above. Not sure if it goes away above that, I'm gripping too tight and concentrating on other things!

[ChrisCar6]

Tried different wheels - same vibe.
nothing loose I can find in the front suspension.
Steering column universal joint is new, solid one.
Front tie-bar is UJ.
Does the speed it happens at indicate anything? I'm not clear about Michel's test - it will always go away when the speed drops below 70.
guess a geometry check is cheaper than new shocks...

[David J]

Hopefully got to the bottom of the wheel shimmy, I put on my old alloys back on the front complete with 205 tyres, no shimmy, it felt so much better on the road. My conclusion is that 225 profile tyres are too wide and have an detrimental impact on the steering.

David

[David J]

An Update on the wheel shimmy problem I have suffering from at 60 mph and above. I have finally got this irritation sorted with some help from Chris Jarvis. Basically the centre of the wheel must match the diameter of the hub. In my case the centre of the Minilite measured 66.6mm, the hub diameter measured 57.6.

In order to make up the difference SPIGOT RINGS are available in a variety of sizes in tough plastic or aluminium. BINGO the problem has now been resolved no more wheel shimmy at 60 plus mph.

If any one else is suffering from a similar problem it would well worth checking that the centre of the wheel matches the diameter of the hub.

David

[Normb666]

So what you're saying, if I understand it correctly, is that the mating surface of the inside of the wheel that contacts the hub must be the same size as the hub mating surface, or you get shimmy. Bloody L. I'd never have thought such a thing could make a difference, and in fact it's not even something I'd ever considered that could affect...er....anything!

I'm trying to work out why this would happen, but I'm coming up blank. But it must be a known issue if you can get something to eliminate it! Congrats to you both for sussing it! - although it seems to have taken you 7 years :)

[ChrisCar6]

I'm struggling to understand the physics of this too. You're saying that the shimmy is not coming up the shaft from the wheels, but is due to a possible eccentricity in the steering wheel to hub join?

Ignore this, I misread the post and got hold of the wrong end of the column completely!

[Longtimefan]

Are you saying that the wheel bolts/studs were not securing the wheels in a truly central position on the hub, and therefore allowing the wheel to be slightly off balance?

[ProtoTipo]

The centre bore on all production car road wheels is centred to the the spigot on the hub/flange.
The weight of the car shouldn't be taken by the wheel bolts/studs alone.

It's an important engineering feature.

For David's sake, I wish I'd had that in mind when I ordered the Minilites for him.

Having said all that, David's classic 5 spoke Revolutions (which the Minilites replaced) have sleeve bolts with no taper, and no spigot feature at all.
That type of sleeved bolt/stud is not typical though.

It seems that some aftermarket wheels are supplied with spigot rings, rather than having the wheels machined to specific centre bores.

[David J]

My original thinking on this matter was that the wheels would automatically be centred on the hub by means of the matching tapers on the wheels and bolts, this is not the case. The wheel has to be centred first on the hub ( the hub is baring the weight of the wheel) This only achieved when the diameter of the hole in the centre of the wheel is sliding fit over the hub. You will find that all production cars have matching diameters.

It is amazing that it has taken me so long to get this problem sorted out, I was completely unaware that this mismatch between wheel and hub could cause the problem I have encountered all these years.

The original wheels on my car were Revolutions which were secured by wide shanked bolts (no tapers) directly on to the hubs. I did not experience any shimmy which those wheels. The hub to wheel alignment must have been absolutely accurate using this method.

[Longtimefan]

Just think David, you have had 7 years of vibrio hand massage, that you wouldn’t have had with the old wheels. Be positive, keeps any ailments of stiffness at bay!

[David J]

The first run in the car with the spigot rings in place was a revelation, at 60 and above the steering wheel remained still. No more vibrio hand massage. I was like a dog with two c**ks.

[Normb666]

So basically, the wheels were off-centre to the hubs which caused the vibration. I'm sure I've come across cars without a hub spigot though, although I can't remember which ones...as you say, you'd think the tapers in the wheel bolt/stud holes would self-align with the tapered bolts/nuts.

[David J]

That’s what I thought, the tapers on the wheels and bolts would centralise the wheel on the hub. Apparently not enough resulting in steering wheel shimmy at speeds of over 60. Spigot rings are commonly used if Audi wheels are fitted to Skoda’s.

[ProtoTipo]

So basically, the wheels were off-centre to the hubs which caused the vibration. I'm sure I've come across cars without a hub spigot though, although I can't remember which ones...as you say, you'd think the tapers in the wheel bolt/stud holes would self-align with the tapered bolts/nuts.

Norm,
Craig explained the importance of the wheel centre bore matching the spigot to me a couple of years ago.
You can ask him for clarification, but he won't have time to answer you!

[Normb666]

I think part of the problem is that on an enthusiasts' forum like this, you come across all types of bores, so you tend to let a lot of stuff slide past.... And yes I include myself in that category! :)