wheel bearings

[kpb]

After spending a morning doing the geo on my S1 after fitting the new suspension now that all the Koni knocks are gone I can hear a wheel bearing drone after 40mph ( I should have left the noisy shocks in )
It is faint but there all the same and seems to be less noisey on left hand bends.
I seem to remember that this means it is a R/H bearing (24000MLS old) from something I read about the transfer of load during cornering.
I have jacked uo the car and there is no play on any bearings so I thought I had better get two bearings and do them both.
Being Scottish I thought save money and see what the general opinion is before changing both bearings.
Cheers
Kinnon

[robin]

Change neither until you know which one is broken.

If you're turning left then the right hand wheel is more loaded and the left is less loaded.

If the noise gets quieter on left hand bends then it's probably the left hand bearing that is away (a worn bearing makes more noise when loaded).

BUT this is only probable - it could still be either bearing.

If neither bearing has any play and neither bearing feels rough when spinning the wheel, I would be inclined to wait until one or other of these symptoms presents itself. You can run on shagged bearings for ages, though I would advise changing the bearing as soon as you can identify which one to change.

Beware that sometimes the stub axle has worn and so changing the bearing itself won't fix the problem. So when you dismantle the failed side, use calipers to measure the outside diameter of the stub axle all the way along - it should be parallel - if it tapers at one end, you must replace it.

Cheers,
Robin