Noisy rear end since tyre change

[Finster]

Hi All,

I recently had to change the back tyres on my 2006 Forester after getting a big puncture. I was running continental ContiCross tyres and have to say they were brilliant.

Couldn't get the same again due to delivery problems and so ended up with continental ContiContact 2's instead. I was never happy only replacing a pair as the fronts were 50% worn

and so got the garage to order a second pair for me. There was a delay for a couple of months before I finally managed to get the front pair replaced as well.

The car has now developed a noise from the rear end which isn't a whine and isn't a rumble, but sounds like the noise a tram makes ! It starts at about 20mph and gets really loud at about 50mph, after which wind noise and engine noise mask it. At 50mph it's loud enough to have to raise your voice to be heard. The garage say it's tyre noise, but I can't believe it would be so loud on a premium tyre like that.

My question is - is the diff fragile enough to be damaged by a 3-4mm difference in tread depth between front and back over a couple of thousand miles ?

Second question - how can I check it's the diff and not a wheel bearing or prop shaft bearing ? There's no vibration in the drive train and the car has 120,000 on the clock

Thanks for any help 

[Judd]

It's surprising just how loud some tyres can be, the winter set on our Foz make the sound you describe, perfect description by the way tram like, especially noticeable in built up areas when slowing from say 30mph when the sound is reflected from surrounding buildings. First week after i fitted them for this season wifey asked me if there was a wheel bearing on the way out, its not its the noise the tread pattern sets up, soon as the summer set of Falkens go back on the noise will vanish.  Have all season Yokohamas on our Prado with much heavier AT tread pattern and those are really quiet but the Prado is well soundproofed from the factory, some tyres just kick up a racket..

Those conti cross contacts are proper all terrain pattern with multiple sipes as you would find on a typical full winter tyre doesn't surprise me they are making a noise, our generation Foresters are not very well soundproofed, might be worth investigating fitting some of those rubberised self adhesive sound proofing pads you can buy relatively cheaply, i haven't done so with the Foz but have seen big improvements doing this with other cars.

[Finster]

Hi Judd,

Thanks for the reply - useful to know you've had a similar experience. Weirdly the Foz was OK on the ContiCross all season tyres and it stuck to the road like the proverbial on a blanket. It's the road biased ContiContacts that are making the racket and it tramlines horribly on white lines or any ridges in the road surface now, which it never did with the previous tyres. So long as it's tyre noise and my diff isn't going to go bang, I can put up with it !

I think I'll try and pick up a second hand set of winter wheels and see if that makes any difference