View Full Version : Concern over post about AWD system.

08-17-2001, 05:35 PM

I'm a bit concerned about some of the posts that I have been seeing about having to replace the AWD system because of some of the tyres being more worn than the others.

So, I have a few questions:

1. After how many km's should I rotate the tyres?
2. Do I need to replace all the tyres if 1 of them fails/blows?
3. Is this something they check when the car is serviced as I'm not that much of a car wiz (I just like driving them http://xc70.com/iB_html/non-cgi/emoticons/smile.gif  )?
4. I'm waiting for my new XC to arrive it the next couple of weeks. Is this covered off in the manual?

Thanks in advance.


08-20-2001, 04:43 AM

I got a very useful reply on Volvospy and I thought I'd share it here:

"I have a Y2K Classic XC and the central and rear differentials burnt after replacing two rear tyres by Michelins of a different pattern (one was damagged but I changed both as the old ones had been discontinued), but of the same nominal size. After much fuss with Volvo about the cause of failure, they said that the new (larger) tires must be placed at the front always. They recomend that all 4 tyres must be exactly the same, but a recomendation is just that.

While I had this problem, a friend took his XC to replace the front tyres and they installed Michelins with the latest pattern, so the front and rear axles had different tyres and he has had no problems.

The spare tyre is of different size and pattern, but Volvo says that driving at the low speed allowed for the spare tyre will give no problems; the trouble is when driving at higher speeds with different tyres.

Also as front tyres wear out sooner, they will always be smaller....Again Volvo did not give a technical explanation, but unofficially they recommended the rotation.between front and rear tyres.

I really do not believe that the slight difference in size between new tyres and mid-worn ones, can cause the disaster I experienced, because there can be a bigger difference in size just due to lower pressure in some tyre (as is probably the case in 90% of cars running around).....Volvo did not give me an explanation to this argument.

In resume, tyres must be of same nominal size in both axles; tyres in the same axle must be exactly the same; pattern in front and rear can be different; new (larger) tyres must always be at front.

I asked Volvo why they do not explain all this in the userīs manual, where they just warn that all 4 wheel must be of the same nominal size.

In case you cannot find the exact tyre to replace a damaged one, you must change two."


08-20-2001, 11:51 PM
Great reply! Does anyone have any specifics?

I think I read somewhere that the tires cannot differ great than 2mm, I assume in terms of tread depth. Perhaps the tolerances in the drivetrain do not allow differences up to a given (and known) point?

Also, in the reply, though he had the pair replaced, a different model of tire was installed.. is this ok?

02-24-2002, 05:20 AM

on top the DSTC might get confused if the diameters differ too much. Instructions manual of my wife's golf V6 with 4WD and ESP says that.

03-16-2002, 05:45 AM
When I took delivery of my '02 XC, the dealership service manager emphasized the importance or rotating all four tyres every 7,500km (5,000 mi) i.e. every six months under average usage.  This is repeated in the '02 owner service manual.

My wife had a similar problem with a Toyota Corolla SR5 4WD wagon back in '96.  We bought the car in '89 and two of the Japanese Dunlop tyres on it developed alarming bulges after a few weeks use.  The dealership replaced just those two tyres, but with the nearest Australian equivalent. Eventually both the rear and centre differentials had to be replaced, largely at Toyota's expense.