Petrol 2.5s.starts about 65 and continues through 90. It's not terrible... Just spoils the cruise Drop down to 60 and it disappears. Its not the road sutface and I don't get any noises over potholes or speedbumps.. The car is new to me so any ideas on where to start?... Wheel balance?

 

Welcome to the forum stephen44,
Please post an intro in the new members area when you can.
Balance is probably a good place to start.

 

Stephen44, Welcome to the Forums. Lots of good info here. Odds are, you have either a balance issue or a bent rim. The first thing I would say to do is to rotate the tires front to rear and rear to front. Does the shimmy remain the same. If so, then odds are you have a slight misalignment of the suspension and a simple 4 wheel alignment will fix this issue. If the problem changes magnitude, then you either have a wheel that is not properly balance or the wheel is slightly bent. This is where if the problem went way, then rotate the tires back only on 1 side of the car and see if the problem returns. If yes, then the front wheel on that side needs some TLC. If not, then it is the rear wheel on the side that was not rotated.

If you are suspecting a balance issue, ask the tire shop to do a runout test on the wheel. This will measure the straightness of the wheel. Granted, you can most likely look at the edge of the rim and see the bend in the rim with a slow rotation (about 1 revolution per second) as it takes that much of a bend to really affect things.

On a side note, just because you found 1 wheel that is bent, do not assume you are done. It is not uncommon to find multiple rims with issues.