Strange Wear And Vibration

[ee0u30eb]

Hello everyone,

I hope someone can help me to figure out what is wrong with my MK1 focus (02 TDI Ghia). I think this problem started after I span in a diesel spill which sent me sideways into a kurb. All damage was fully repaired by insurance in theory.

I began to notice vibration in the steering wheel at speeds berween 70 and 80mph, and after some time I found that the two front tires became very worn on both the inner and outer edges. I took the car into a Ford garage for a full service and asked them to look into it. At this point the tires were not illegal as the centre tread was still good. However they did replace the back tires and did the usual balance etc. They had nothing to say about the vibration.

So vibration still there, I kept going until the two front tires did need replacing, which happened to conincide with needing my cam belt replacing at 100k. So I went to a different Ford garage and stressed that I wanted the fron tires replacing but only if they could get to the bottom of the vibration and wear. The mechanics took a look and checked all the bushes, said there was no play in the steering and confirmed that the tracking was bang on, but could find nothing else and suggested that perhaps the tires were under-inflated. I dissagreed but asked them to continue and replace the tires, and check the alloys for any damage. They replaced the tires and balanced the wheels etc, but still the vibration is there.

The ford garage has offered to take my car in overnight and the owner will test drive it a bit more thoroughly, but I haven't got time right now.

The vibration is definately in the steering wheel, if I put one hand onto the handbrake, or dash I cannot feel it anywhere near as much as in the wheel.

I do not want to go through my new tires, or have this discomfort anymore, it drves me nuts!

Many thanks in advance

[mjt]

I've noticed similar wear patterns on my Mk1. They wear along both outside edges even though I check the pressures regularly. This pattern of wear is consistent with running under inflated and I've come to the conclusion that the pressures are wrong for the diesel-engined car. The diesel lump is heavier than the petrols yet the tyre pressures specified are the same for both which doesn't seem right to me. I've started running my front tyres a few psi higher to see if that helps. Trouble is I don't know what the actual weight difference on the front wheels is so it's difficult to know if I've increased it enough.

As for the vibration that just sounds like poor balance. I've found that when you get wheels rebalanced the machine often doesn't do an optimum job unless the fitter strips off all the old weights first. It also depends how careful the operator is. If you're absolutely sure the balance is ok then it might be a distorted wheel. Were any wheels that contacted the kerb replaced as part of the repair? Even if the rims are not dented you might have one running slightly out of true.

[ee0u30eb]

As for the vibration that just sounds like poor balance. I've found that when you get wheels rebalanced the machine often doesn't do an optimum job unless the fitter strips off all the old weights first. It also depends how careful the operator is. If you're absolutely sure the balance is ok then it might be a distorted wheel. Were any wheels that contacted the kerb replaced as part of the repair? Even if the rims are not dented you might have one running slightly out of true.

Thanks mjt. Intersting thought about the PSI, so you running at 35psi now?

No wheels were replaced as far as I am aware. How/where can I have the wheel checked for distortion?

I will assume for now that the balance was done correctly. They have been rebalanced after alla nd the vibration has not changed, I would have expected some change even if it was still incorrrect.

[mjt]

Yes, I'm running about 35psi now but I've no idea if that is correct for the weight. I think the tyre manufacturers publish figures for pressure versus weight but,as I said, without knowing the actual weight that is not much help. It's actually quite important to have the correct pressure because that maximises the contact area.

If rebalancing made no difference at all I'd suspect a wheel running out of true. If you jack the car up and spin each wheel you might be able to see it if it's bad enough. Other than that I guess a tyre depot could put them on the machine and check them for you.

[ee0u30eb]

Just wondering if perhaps swapping front and rear wheels would be a good idea to help diagnose this? That way I could possibly rule out the alloy. What are the chances of it being the wheel hub?

I don't imagine I will be able to see if the alloy is distorted... when brake discs are warped you can't see it and need a special tool to diagnose it.

[mjt]

You've nothing to lose by trying swapping the wheels around and a good chance it might localise the problem. Personally I doubt if it will be the hub. If you'd hit hard enough to bend it it would have done serious damage to the wheel as well.