Steering vibrates at 80 mph and over

[wannabemedic]

Hi folks

I used to have no probs even going up to 85-90 but since I had two tyres replaced (new ones fitted to rear, and existing rear ones moved to front) the steering vibrates just as I get to about 80mph.

According to sat nav it's actually only 73mph when this happens.

I went back to garage to have balancing redone, so they took the little weights off the wheels and rebalanced them. I saw them do it and the machine said it was ok after they'd finished.

In the past we had 4 new tyres and to solve the same vibrations I think they put a wheel on the rear which worked out well. Obviously that was a temporary fix, do you think a wheel could be buckled (wouldn't that show up on the balancing machine?) or maybe something with the suspension?

[oakdale]

What make are the tyres moved from the rear to the front? Some cheap and cheerful tyres aren't even round in shape.

Edited by oakdale on Wednesday 10th December 12:41

[Sam_68]

It could be a sticky brake caliper and/or a slightly warped disc, or it could be a bent wheel, but the fact that the vibrations only set in at about 80 seems to suggest otherwise.

To be honest I'd put money on it simply being a muppet at the tyre centre who hasn't balanced the wheels properly.

If the wheel is bent, you can usually tell visually simply by jacking the wheel up and spinning it over by hand... fix your sight on one point on the circumference; if the wheel is bent that point will seem to move in and out as the wheel rotates. If it's the brakes, you'll hear them grabbing once per revolution of the wheel when you do the same test.

[wannabemedic]

The tyres are all Dunlop SP30s, the ones moved to the front have about 4-5mm tread depth.

I have a feeling it could be the wheel that's buckled. After all this time they balanced it with the centre manager there and it's sorted the vibration to a certain extent but not completely. It was at Kwik Fit and I know, they're known for being muppets, but at this centre I know the chaps and they're pretty good. Besides the balancing was done on a machine anyway.

Sam 68 - thanks for that idea, I'll give it a try (never jacked up a car before!) and post back here.

[tlracing]

Sam_68 said:

It could be a sticky brake caliper and/or a slightly warped disc, or it could be a bent wheel, but the fact that the vibrations only set in at about 80 seems to suggest otherwise.

To be honest I'd put money on it simply being a muppet at the tyre centre who hasn't balanced the wheels properly.

If the wheel is bent, you can usually tell visually simply by jacking the wheel up and spinning it over by hand... fix your sight on one point on the circumference; if the wheel is bent that point will seem to move in and out as the wheel rotates. If it's the brakes, you'll hear them grabbing once per revolution of the wheel when you do the same test.

+1

Does the vibration get worse then slowly go off again? If so, it's very likely to be a wheel that's slightly out of balance, just hitting a frequency at that speed.

Anyway, I presume you'll only be doing 80-90 on private roads????

[wannabemedic]

tlracing said:

Sam_68 said:

It could be a sticky brake caliper and/or a slightly warped disc, or it could be a bent wheel, but the fact that the vibrations only set in at about 80 seems to suggest otherwise.

To be honest I'd put money on it simply being a muppet at the tyre centre who hasn't balanced the wheels properly.

If the wheel is bent, you can usually tell visually simply by jacking the wheel up and spinning it over by hand... fix your sight on one point on the circumference; if the wheel is bent that point will seem to move in and out as the wheel rotates. If it's the brakes, you'll hear them grabbing once per revolution of the wheel when you do the same test.

+1

Does the vibration get worse then slowly go off again? If so, it's very likely to be a wheel that's slightly out of balance, just hitting a frequency at that speed.

Anyway, I presume you'll only be doing 80-90 on private roads????

Of course

Seriously though when my speedo shows 80, sat nav usually says about 73mph and I don't ever go above an indicated 80. It's only when I get into the third lane on a motorway and some **** in an Audi presses his snout right up as if it's their private unrestricted lane. I try not to get intimidated but it's difficult knowing what to do, apart from slamming on the brakes and making a whiplash claim... lol.

Anyway, I jacked both front wheels just off the ground and really couldn't see anything odd when spinning them slowly... I take it there's no safety risk if it's left as it is now?

Edited by wannabemedic on Wednesday 10th December 21:08

[GreenV8S]

It could be out of balance or out-of-round. Or it could be a bit of dirt dropping between the hub and the disc while they had the wheels off preventing the disc/wheel from seating properly afterwards. (You might notice the pad knock-back from that, or you might not.)

[tlracing]

My only other thought is that the vibration is one of the new tyres. sometimes these get little balls of rubber/release compound rolling-up inside them which can affect the balance as they're loose.

[chevy-stu]

Have you checked all suspension bushes/ball joints and steering components, track rods etc.. ? even though it tracks straight sometimes can be these..

[DaveV6]

I'd take the front wheels off and clean up the hub and wheel surfaces first, it might just be some corrosion on the hub/wheel. If that doesn't sort it then try swapping the wheels front to back (you say they put the older wheels/tyres on the front) and see if the vibration goes away.

[wannabemedic]

We had all four tyres a few years ago and vibrations back then were only solved by swapping fronts and backs.

However I hear that newer tyres should always go on the back.

I understand this to be due to the increased depth on the newer ones, so if aquaplaning you feel the front lifting which isn't as bad as the back skidding out.