S40 T5 slight vibration under acceleration

[Welton]

This occurs at around 65-75mph - if I accelerate hard then I can feel a slight vibration! it's not too bad and doesn't shake anything but it's there.

Under 60mph and over 80mph it's gone.

I have had 2 new tyres on the front because they were needed anyway all balanced ok and I got them to spin up the rears on the balancing machine but one wheel has a very slight deviation when it rotates (a buckle I suppose) and they could only balance it down to within 10 grammes on the machine and popped it on the back axle.

Is it possible that with a fairly tight chassis like these that I would feel a slightly out of balance wheel or could it be an engine mount? - the car is not yet 4 years old with 24K miles.

Thanks

Welton

[CONDYBOY]

you may well feel the wobble from the wheel but I would expect that to be above a certain speed and to get worse as the speed increases, i would check the driveshafts and cv joints aswell as the engine mounts. if all is well change the wheel from rear to front and see if you can then feel the vibe through the steering.

[jez.w]

Take the car somewhere else and get them balanced again. I have had similar problems before with badly balanced wheels. If you look at the age and condition of some of the machines that balance wheels its not suprizing that the machines probably need balancing themselves. I have had tyres fitted where the balancing was way out at high speed on the drive home from being balanced, and i took it back straight away to be checked and they said that the wheels were perfectly balanced (which they were not). I have had this at two different tyre garages now. So I took my car to another place and got them re balanced which has cured problem both times (using new looking clean machines). Both times i had bad vibration through the steering at 70 ish which improved as speed increased to almost nothing at 100. As most of my driving is done at around 70 on dual carrageways this was no good. I suppose i could just not exceed 60 and i would never have noticed??? If the tyre garage that sorted out my balancing both times did good deals on tyres i would have gone there for the tyres and balancing in the first place. I am not the only person to have this problem, i have dicussed this with other people before and it seems quite common.

[Welton]

Thanks for the replies, It feels a bit weird again at the moment after I inflated my tyres to 32 front/35 rear for a fully loaded motorway run at the weekend - it feels like the tyres are rock hard (which they are I suppose).

I'll drop the pressures tonight when it's cooled down and see what goes.

There's definately something not right though so I may well go to another tyre place (there's one of those blinging-rimz places in town, surely they'll have a blinging new balancing machine?).

Welly.