Vibration: tyres?

[alogbe]

I recently had new tyres (Michelin Pilot Primacy) fitted to my A6 Avant. Since then I've noticed a very slight vibration for the first two or three miles after starting from cold. At first I would have said it was from the engine, but it continues if I put the gearbox into neutral and just coast.

After that initial period it goes away completely; even at motorway speed there's no suggestion of a wheel being out of balance.

I've heard of tyres developing a temporary flat spot if the car is parked for a long time, but this car is used almost every day.

Does anyone have a suggestion?

[Corb2000]

Could you give some more info please - engine and gearbox combination, mileage, wheel and tyre size, tyre pressures - would all be useful.

[alogbe]

Could you give some more info please - engine and gearbox combination, mileage, wheel and tyre size, tyre pressures - would all be useful.
2.7TDI manual; 68,000 miles; 225/55 16"; front/rear 36/30 psi, 2.5/2.1 bar (as recommended by manufacturer for a light load).

[Corb2000]

Two ideas then:

1. Sticky ABS sensor on one of the front wheels, other people have reported getting slight vibration through the brake pedal and steering after cold starts which goes after a few miles. Solved by cleaning the sensors on each brake caliper.

2. Problem with power steering pump, which may again only manifest itself when the pump & its oil are cold.

Anyone else have any suggestions?

[Corb2000]

Unrelated problem but someone reading this thread might have an idea – my 3.0 multitronic is smooth as anything except for a strange coarseness / vibration through the steering wheel which happens when accelerating through 1800 and 2100 rpm in auto mode or in numbers 2 to 6 of the manual ‘gears’, (don’t feel it in first for some reason).

It is also present, although much less noticeable, when decelerating through the same rev band. It is also more noticeable when holding the bottom of the steering wheel.

I have 18” wheels with 235/40 Pirelli P Zero and Michelin Pilot tyres and did put the vibration down to poor absorption of road surfaces for a while but after much trial and error have isolated the feeling to these revs rather than speed or anything that’s happening on the road. It does not seem to make any difference whether the wheels are straight or turned.

My car’s done 47k and has the multitronic oil changed in the last 2k. Is this coarseness / vibration yet another multitronic quirk or could it be something else? Any ideas / advice please!

[paul b]

Unrelated problem but someone reading this thread might have an idea – my 3.0 multitronic is smooth as anything except for a strange coarseness / vibration through the steering wheel which happens when accelerating through 1800 and 2100 rpm in auto mode or in numbers 2 to 6 of the manual ‘gears’, (don’t feel it in first for some reason).

It is also present, although much less noticeable, when decelerating through the same rev band. It is also more noticeable when holding the bottom of the steering wheel.

I have 18” wheels with 235/40 Pirelli P Zero and Michelin Pilot tyres and did put the vibration down to poor absorption of road surfaces for a while but after much trial and error have isolated the feeling to these revs rather than speed or anything that’s happening on the road. It does not seem to make any difference whether the wheels are straight or turned.

My car’s done 47k and has the multitronic oil changed in the last 2k. Is this coarseness / vibration yet another multitronic quirk or could it be something else? Any ideas / advice please!
Vibration through a certain rev range can be caused by a faulty DMF or clutch, but without driving it I couldn't say. Peter D in the A6 section, or Crasher or A8 Tech could probably help you.

Then again, the above wouldn't be through the steering wheel.

I think then it would be time to get someone with an experienced eye to have a look at the driveshaft.

[alogbe]

Thanks for the two ideas.



1. Sticky ABS sensor on one of the front wheels...
2. Problem with power steering pump...