Definitive list of wheel wobble causes

[Grrrmachine]

A new bit of road has opened up on my way to work, so I get the chance to drive at autobahn speeds every day. Now I've discovered that a vibration kicks in at 90kmh, and stays there up to 140km/h (I didn't want to push the car any faster).

Things I've checked:

1) Wheel balancing. Wheels were done a year ago, only used for four months, and all weights are still present.
2) Tyre pressure. Fronts at 2.3 bar, rears at 2.5.
3) Tracking. Fitted a new rack a month back, reused the old track rods, and checked with the string line that the tracking was good. Seemed ok to me. Rear has an adjustable beam that was set up last year.
4) Control arms. The ball joints were replaced 3000 miles ago.
5) Bearings. Jacked the fronts up and gave them a good shake, and couldn't feel any play in them.
6) Mounts. Engine and gearbox mounts, plus the propshaft guibo, were replaced 6000 miles ago.
7) Bushes. Rear beam was overhauled 6000 miles ago, but I haven't touched the front suspension since I bought the car in 2009.

What else do I check? Other than paying 25 quid to have a pro check the tracking again, or having the wheels rebalanced, I'm at a bit of a loss. The vibration isn't strong enough to shake the car apart, but it's certainly not something I'd want on a long road journey.

[Grrrmachine]

The vibration is through the steering wheel, so it definitely seems front-related. However, the amount of weights the balancers fitted clearly show which wheels should be on the front and which on the back.

The oddest thing I found was swapping the left and right front wheels over seemed to reduce the wobble - even though the treads were running the wrong way round (I've got Toyo Proxes on) - although that might just have been in my head.

Pothole wise, who knows? These are Polish roads after all.

[Speedtouch]

I presume your wheelnuts are all tight? As above, try swapping the wheels over from front to back.

[Grrrmachine]

Ok, plan is to systematically swap each wheel in turn to see how it feels. I've just swapped over the driver's side wheels, so I'll take it out for a spin - if the wobble's still there then I'll try the same with the passenger side.

[Speedtouch]

Also, when you have it jacked up, give each wheel a spin and check the roundness, both on the outside and inside of the rim and tyre - it's not unknown for there to be a bulge on the inside that gets overlooked.

[Brianmoooore]

What state are the control arm bushes in? They can be responsible for wheel shake, but normally only under braking.

[capnmchl]

What state are you wheel and hub flanges in? Corrosion build up there can lead to wheel wobble.

[Grrrmachine]

It must be wheel related; swapping the front and rear wheels on the driver's side has eliminated the vibration. So either that front wheel is out of balance, or there was something on the hub that caused the wobble that's since been removed.

[daimlerman]

I would be examining that ex-front wheel for Polish road damage!

[satan16v]

Could be the tyres themselves, had similar symptoms on my X5, replaced the rear tyres, problem went away

[Taylor325i]

Sounds like a buckled wheel (or wheels) or flat spots on tyres. Has car sat for any length of time without being moved? This will cause a permanent flat spot on your tyres.

Taylor.