2003 XC70 tyres queries

[Stuart]

Hello all, I've just come across this website, and it looks an excellent source of information. I'm hoping that a couple of you may be able to offer a newbie XC70 owner a useful comment or two.
I have just bought, and will obtain in a few days, a May 2003 XC70 D5 SE Geartronic in Nautic Blue with 15,000 miles. I'm no stranger to Volvos as you'll see below.
Reading through the XC70 handbook and paying particular attention to the sections on wheels and tyres, and the transmission info (this is my first AWD vehicle, and in fact first diesel) I found a couple of items that I'd appreciate advice on.
1. There is an "IMPORTANT" comment added to the statement that the deepest tread tyres must always be fitted to the rear of the car "regardless of whether it is front or rear wheel drive". Clearly it's not exactly the case with the XC70 AWD but my assumption has always been before that the steering and braking load, and now with this AWD car also the major part of the drive are put through the front tyres, and it seems to me that's where I'd like the grip - so I don't understand that!
2. Looking around the Internet I've picked up several comments that the tread depth (rolling diameter really) on all 4 tyres is hyper critical (2mm variation maximum was one figure) to protect the diffs. I can see that the left/right balance would be important, but is the front/back that critical? How on earth do you cope with tyre wear when I could see that the front could be down near the sub 2mm limit, whereas I would guess the rear could conceivably be over 4mm? Bin the 4 at the same time?

Any comment from AWD owners would be appreciated.

[TrueBlue]

Don't panic Stuart, (BTW welcome to the forum...) The comments about AWD tyre depths and which axle to place them on was only critical on the Viscous Coupling afflicted models which wer pre 2003. Your car has the Haldex system which is electronically controlled and the manufacturer specificaly states "no problems", see here - http://www.haldex-traction.com/default.htm, under "Technical information":-
Quote: Enhanced Vehicle Driving Comfort and Transparency
- No wind-up during tight cornering and parking.
- Optimal traction during acceleration.
- No functional problems with tyres having uneven wear,
- pressure or size (mini spare).
- No functional problems when towing with one axle lifted.
- Transparent actuation. Endquote:

With the standard supplied STR's you should have plenty of miles left on your current set of boots, so no need to worry unduly yet. When you do need to change, think about Nokians (possibly not the WRs 'cos they're not available here but NRZi's.) Our US friends rave about them - do a search on this forum.

Do keep posting, Brits are very much in the minority here, so we need a lot of chat to keep our end up....

Does your car have DSTC?
Is the interior have light sand leather (most usual with Nautic)?
Let's have the full spec.

regards,

[XC70Geo]

Stuart,
Q1: "The deepest tread tyres must always be fitted to the rear of the car." It's for better traction while breaking (stopping) on snow, ice.
Q2: Equal diameter - as TrueBlue said - is not critical for Haldex.

BTW: I change the front and rear pairs every 6-8 months. It's an AWD, but front tires wear more.
Nautic Blue is a great color, congratulations.

[Stuart]

There you go, I was right, this is going to be a most useful website/forum. Thank you both for your rapid replies. I'll sleep easier tonight!
I thought it was strange that if there was a major restriction on tyre tread variation then why wasn't it mentioned specifically in the handbook. Now I know why - there isn't a problem. I have now looked at the Haldex website, very interesting.

Mike - interior of the car is Light Sand, and very nice the combination is too. I'm really looking forward to getting and using the car. DSTC, now there's a thing. I read about it in the handbook and assumed it was standard fit? Have to admit I didn't look for it on the car when we test drove etc.. Still, I'll check that on Monday when I get it. Thanks for the Nokians comment, I'll bear that in mind.

XC70Geo - thanks for the rear tyre explanation. I can understand that from the braking stability situation.

I can see me spending a lot of time browsing through these forums. I have already found out quite a lot of interesting info from various queries and comments.