Acceptable disc run-out? Or do I try wheel balancing again

[ruaricoles]

Hello peeps,

My Griff 500 has developed steering vibration at motorway speeds, which seems to feel a little worse under high speed braking.

I assumed it was the tyres, so had them rebalanced, and while they were a bit out of balance, the problem is still there.

I then assumed warped discs, so just measured the disc run-out but it's only about 0.10-0.15mm on each side. It doesn't seem much, but is this enough to cause an issue? They're standard 500 brakes. Judging by the state of the inside faces, the sliders are working acceptably although there isn't quite full pad contact.

I've got some replacement discs and 1144 pads waiting, but there's plenty of life left in the current ones yet so don't want to swap them over if I don't need to.

Do I try a different tyre place for repeated wheel balancing again first? I could do with new tyres soonish so it's a pity to keep rebalancing the old ones!

I've not had a good poke around the bushes yet, but the wishbones and dampers are only a couple of thousand miles old so unless something is loose I'd be surprised. I'll check tomorrow before doing anything else.

The wheels themselves are running true.

Any suggestions?

Thanks

Ruari

[J400GED]

Possibly worn balljoint or track rod end?

Ged

[haircutmike]

I'd put the new tyres on and then start looking elsewhere if it still occurs.

It's unlikely to be the brakes as you're not braking when it happens.

[spend]

Pull the discs off & clean + Cu.Slip the mating faces twixt hub & disc then re-check the run out. Whilst they are off check the run out on the hub face and 'feel' the bearing etc..

[ruaricoles]

Thanks for the suggestions, guys.

I had another poke around this evening and still can't see anything obvious. Suspension all seems fine. Still a teeny bit of runout on each disc having tightened them back onto the hubs - on one side just enough to touch the pad as the disc rotates, but nothing I'd have thought severe enough to cause the vibration. Wheel bearings seem OK too.

I think I'll take the front wheels to a different tyre place tomorrow, and if they are still unbalanced hopefully that will be it. I don't really want new tyres yet - there's still a few mm left in them.

If the tyres are fine, then I'll fit the new brakes. If that still doesn't fix it, I'll just have to drive in skiing gloves so I can't feel the wobble.

[davetherave1970]

Does anyone know if they can be balanced on the car? Or is this a bad idea as you'd hide any other problems waiting to "happen"?

[ruaricoles]

Looks like it was the tyres after all - I took them to a different tyre place and one of them was 30g out. In fact, it's gone a little off-round so it's definitely time for a new set soonish.

Haven't driven the car again to check but presumably that was the issue. I don't think I'll be using the first place I took them to again...

Thanks for the suggestions

Ruari

[J400GED]

Glad to hear it was something simple mate.

Ged