Wobbly steering wheel

[Captain Jack]

So I replaced my pretty balding tyres yesterday, Toyo Proxes C1S, with Avon ZV5. While enjoying* my drive* this morning, I noticed that at, ahem, motorway speeds the steering wheel shakes. I've had this before on carpy tyres and no amount of wheel balancing resolved it. I ended up replacing them.

However, I don't want to do it this time, considering it wasn't exactly cheap. The wheel vibration is not horrendous and comes in waves - almost as if they go in and out of alignment with each other. What causes this? And why is it not vibrating all the time? Is it just a matter of poor wheel balancing or faulty tyre(s)?

It did not do this with Proxes, so it's definitely the tyre replacement that caused this.

I won't get a chance to go to the garage until Tuesday now, so thought I'd get people's opinions first.

[KozmoNaut]

Mine did this as well, it had steering wheel shake at motorway speeds. It also seemed like it came and went, and while it wasn't super bad, it was certainly bad enough to be annoying.

I had heard from a friend that "normal" balancing machines actually use an outdated and imprecise method of measuring imbalance, and that I should try a road force balancer instead. Apparently the "Hunter GSP9700" is the most commonly used machine. It'll also measure side-to-side wobble and show where to place wheel weights width-wise on the wheel, instead of just radially (if that makes any sense).

I know I'm beginning to sound like an infomercial now, but found a local tyre fitter that advertised using a GSP9700, and the damn thing actually did the trick, everything is completely smooth as glass now. I have no connections with the company that makes it, or any tyre fitting company for that matter, but I am definitely going to go there again the next time I need new tyres.

I think you can find tyre shops with the fancy-pants machines here http://www.balancemycar.co.uk/. I used a similar website to locate an appropriately-equipped tyre shop here in Denmark.

It cost me ~£55 to have all four wheels balanced, and it was absolutely worth it.

If a good balancing job doesn't fix the wobble, you probably have worn out suspension bushings.

[PeterN]

Both your wheels are slightly out of balance and as you say the imbalance is going in and out of phase depending on the position of the wheels relative to each other, in phase it adds and out of phase it cancels and of course every time you go round a bend the relative positions of the wheels change.

Sometimes you can get tyres that wont balance because there is some deformation in them, you could try swapping the front and back over, yo might just get a combination that works.

Peter

[Captain Jack]

Thanks all. That's what I thought. Will be taking it back to the tyre place - the chap in there seemed friendly enough. If not, I'll try KozmoNaut's suggestion.

[Captain Jack]

Welp, since taking it back and rebalancing the wheels, it's much better, however, still somewhat evident on an occasion. When it does wobble at *ahem* speeds, it's rather minor, so I'll live with it for now.