Technical Steering wheel vibration

[Nickkdx]

Any thoughts on possible cause of vibration through steering wheel on my 2001 Fiat based Hymer B584 , it goes up with speed, I’ve had front wheel balance checked and redone.
I thought maybe wheel bearings but there’s no noise difference either lock and when driving the vibration doesn’t change when going around left or right turns or straight on.
I did have a new cv boot fitted on the offside, outside joint.
Wheel bolts are correct torque and tyres in good condition

 

[bugsymike]

Any thoughts on possible cause of vibration through steering wheel on my 2001 Fiat based Hymer B584 , it goes up with speed, I’ve had front wheel balance checked and redone.
I thought maybe wheel bearings but there’s no noise difference either lock and when driving the vibration doesn’t change when going around left or right turns or straight on.
I did have a new cv boot fitted on the offside, outside joint.
Wheel bolts are correct torque and tyres in good condition

Presumably any distortion of road wheels or tyres would have shown up in balancing the wheels/
My instincts would be towards the o/s drive shaft if fault/vibration happened after that boot fitting. If parts of the constant velocity joint, needle bearings etc. become dislodged whilst fitting the boot they can cause what you describe.
I am guessing there is a centre bearing on the driveshaft mounted on the engine block though usually that would give a whine rather than a vibration.
If access to a "wheel free" garage ramp I would support the suspension as near to the wheels as safe to do so then run the vehicle in second or third gear and check from underneath where vibration worse.
Note this has to be done by a professional to reduce the risk.
Also the support of the front suspension does have to be as near to the wheels as is safe, the reason being if jacked up on the body/chassis the wheels hang down meaning the driveshafts are not in the position they would normally be when vehicle on the road, roughly horizontal with the road.
I have done this many times in the past but it does need care!!!

 

[The Panda Nut]

I had to have one car rebalanced 8 times before it improved. If it was the same place that re did the balance try another place / machine. My current supplier has a really good machine and knows how to use it. It seems not everyone is as competent.

 

[bugsymike]

I had to have one car rebalanced 8 times before it improved. If it was the same place that re did the balance try another place / machine. My current supplier has a really good machine and knows how to use it. It seems not everyone is as competent.

I agree it is down to the competence of the tyre fitter. I have watched many spin up a wheel , fit the weights and stop the machine job done, until I said now spin it up again , to which we found balance still out, many have no interest in their job, more the bonus from fitting unnecessary tyres etc.
In the 1970s I was foreman of a Mazda Dealership when RX3s and 4s (Rotary engines) were popular and fairly quick for their day.
We had customers complain about wheel balance / vibration at higher speeds after having new tyres fitted at the local ATS on their fancy wheel balancer.
In the end I balanced their tyres on a vintage wheel balancer bolted to an oil container at our garage that you spun up by hand and moved an ink coated brush across to mark where to put the weights and a lever that slide along to say how many weights, problem solved , even though some were being used in excess of three figure speeds.