Vibrations with newly balaced wheels

[pmansson]

My 420 G is very smooth up until about 50MPH.
Then I get small but very noticeable vibrations. Small in that it?s not the slow but heavy vibrations that would hint at the prop shaft for example.
New Michelin XWX tyres.
If I look through the rear view mirror, the white roadmarkings become very blurred. If I hold 2 fingers on it, nice and firm, I can see clearly though the mirror

What shall I check next.....?

[Nick]

Were the new tyres balanced correctly ? If there was no vibration before they were fitted that seems to be the obvious cause.

Are they bolt-on wheels or splined with spinners ? If splined the balancing machine should ideally have used a splined adaptor to correctly centre the wheel.

[Heuer]

Try swapping the wheels front to rear and see if it persists. If the fronts are out of balance the steering wheel will shimmy. You can drive through wheel imbalance so the shaking should stop as you go faster.

First port of call should be back to the tyre fitters and get them to re-check the balance. As Nick says, splined wheels need to balanced on a special adapter which most garages do not have. Longstone tyres only do static balancing on these types of wheel. You can do it yourself with one of these: http://tinyurl.com/3x76rsq

[pmansson]

I found a tyreshop where the elder Italian owner/manager has the equipment for balancing the front wheels when mounted on the car.
This did it!
(pretty hairy when he spins them up to over 100 MPH....

NB he first balanced all 4 wheels on the traditional machine, and found that they were not very good at all. Too heavy weights, and a several in the wrong place. I must tell the nice owner of the first place that his machine needs to be calibrated.

[Woolfi]

I I have a similar problem with my EV12. Wire wheels must be fitted to the machine with a OUTER konus, which is pressing to the outer side of the center. Like the wheels are fitted to the car.
Normal adaptors are pressing inside the center of a wheel. Often the mechanics in the wheel-balancing companies are using the wrong adaptor, because they don't know or don't have the correct adaptor.
Kind regards Wolfgang Gatza

Please excuse my poor english.

[1954Etype]

I I have a similar problem with my EV12. Wire wheels must be fitted to the machine with a OUTER konus, which is pressing to the outer side of the center. Like the wheels are fitted to the car.
Normal adaptors are pressing inside the center of a wheel. Often the mechanics in the wheel-balancing companies are using the wrong adaptor, because they don't know or don't have the correct adaptor.
Kind regards Wolfgang Gatza

Please excuse my poor english.

Wolfgang, your english is much, much better than my German!

[PeterCrespin]

Wolfgang, your english is much, much better than my German!

Wolfgang's English is better than your English Angus !

[JEP41]

Hi All,

I purchased from a garage closing down sale several years ago a wheel balancing machine that balances on the car. It works perfectly especially on the fronts but with a power lock at the rear I move the rears to the front to balance them. My machine is I think Australian made by a company called Redline, its quite an old machine now but has seem a lot of service before I bought it judging by the knocks and scrapes it has picked up, but now it is in semi retirement looking after just the family cars. Oh and it balances perfectly 8)