Tyres for 2002 XC70, mismatched brand and tread

[XCnewbie]

I've had my 02 D5 auto XC70 for a few months now. It came with Pirelli scorpion STRs on rear with about 5mm left on them. Fronts are Chinese budget ones which are almost new. Reading around the forums about the viscous coupled AWD system implies it doesn't like mismatched rolling diameters or tread patterns.

So what to do about this?
a) replace all 4 with new STRs. Expensive...
b) live with it? It had a replacement transfer box 40k miles ago
c) get 2 used STRs, approximate wear match
d) get 2 new matching budgets on back

It doesn't get used off road much, just mostly as a family motor. I normally steer clear of budget tyres and head to the mid-range/premiums. Not keen on replacing ones that haven't worn out though! Advice gratefully received.

[JMI]

Hi,

get rid of the cheap Chinese rubbish. I would not recommend them even to anybody who has no money, but enjoys life. Also get rid of the of the Pirrelli STRs, but after they are worn. However they are the only premium brand i would not recommend to anyone. They cost a lot, but they can't match the competition.

Go and get 2 tyres for the moment. I assume you drive on 215/65/16, go and check places like this one

http://www.camskill.co.uk/m64b0s260p...5_16_215_65R16

You have a great choice of tyres like, Hankook Dynapro HP, even better for less than £70 a corner Uniroyal 4x4Street Rallye or even better Good Year Efficient grip SUV - great tyre.

I hope this is any help.
Good luck with your choice!

[upv5]

Technical Service Bulletin 46-0005 shows how the Volvo AWD viscous system works, because there is a freewheel to stop the rear wheels "pushing" the front wheels under heavy braking it does no damage if the rear wheels turn faster than the front.
While you get the most effective 4 wheel drive with all wheels same diameter, if you have to put new tyres on they must go on the front.
If different makes or designs of tyre are used front-rear it makes it much harder to determine the effective rolling diameter, if all tyres are same make/model then you only have to check tread depth to see which are larger.

John

[skyship007]

Some of the best tyre tests are done by the ADAC in Germany:
http://www.adac.de/infotestrat/tests...SourcePageId=0

For 215/65/16 winter tyres:
http://www.adac.de/infotestrat/tests...cePageId=31821

For 215/65/16 summer tyres:
http://www.adac.de/infotestrat/tests...cePageId=31821

In general terms Continental, Dunlop and Michellin lead the pack with Goodyear, Pirelli and Nokian not far behind. Volvo dealers in Germany only sell the best makes in braking performance terms and they are mostly Continentals and Michellins. The Merc dealers who are also very fussy about tyre performance are selling Contis and Dunlops.

Some of the best tyre manufacturers do produce cheaper models, but you get what you pay for in most cases, although you do get a few surprises for particular tyres sizes. For example the Brigestone Blizzak was top of the winter tyre list for 215/65/16.

[ivyhouselady]

I have owned a 1998 V70XC for the last 14 years and was told that you must never have a difference of more than 2 to 3 mm on any of the tyres. We used to move the tyres around to keep the wear even. This was because of the viscous coupling. However, we have now purchased a 2011 version and we checked whether the same applied. We were informed that the system works differently and so there is not the same problem. I am no expert, but I guess you have seen comments on the older system. I do not know when it changed and so your could well be the newer system. I also saw an interesting programme on TV which showed part worn tyres. There was an inspection of garages selling these and it was horrific to see what they were selling. Very few of the tyres were actually fit/safe for use so please be careful if you decide to buy part worn. Close inspection would pick up a lot of the faults such as bad repairs and repairs having been made on the side wall etc. Hope you get sorted.

[JMI]

Originally Posted by ivyhouselady

I have owned a 1998 V70XC for the last 14 years and was told that you must never have a difference of more than 2 to 3 mm on any of the tyres. We used to move the tyres around to keep the wear even. This was because of the viscous coupling. However, we have now purchased a 2011 version and we checked whether the same applied. We were informed that the system works differently and so there is not the same problem. I am no expert, but I guess you have seen comments on the older system. I do not know when it changed and so your could well be the newer system. I also saw an interesting programme on TV which showed part worn tyres. There was an inspection of garages selling these and it was horrific to see what they were selling. Very few of the tyres were actually fit/safe for use so please be careful if you decide to buy part worn. Close inspection would pick up a lot of the faults such as bad repairs and repairs having been made on the side wall etc. Hope you get sorted.

Puncture repairs are easy and not dangerous if done properly! The biggest worry with part worn tyres is age! No matter how good it looks, no matter how much tread it has, the age is key for a tyre! The best tyre manufacturers in the world will give you maximum of 5 years life of a tyre's compound. Other important thing is how these part worns are stored! Most of the dealers should have racks to store their used tyres if not fitted to a rim, they need to be upright, otherwise after some time they'll "bent" and when fit to a rim will vibrate.
So, avoid part worn tyres and buy cheaper, but no Chinese new is my advice. A new tyre from midrange maker is ten times better, than 7-8 years old tyre from the big names in business!
If you consider buying part worns, don't forget to check something very important and easy- the age of the tyre you are buying! It's written on the side wall of every tyre like a 4digit. The first 2 numbers indicate the week and the second 2 the year! For example 2412 means 24th week of 2012 year. It is also know as DOT of the tyre! click on the picture below.

[Simon Jones]

I use STRs on my 04 XC70 which has the later setup which is less fussy about rolling circumferences, but I'm still careful to keep them all of a similar size. While I used to buy new which cost around £90 - £100 a corner inc fitting, I now tend to keep an eye out for nearly new second hand tyres. I've just bought one with 7mm tread for £40 from a former XC owner and that means if I need to replace one, I've got something that is a reasonable match to the existing ones.

[Madmax43]

I run Cooper Zeon tyres on my '99 XC AWD. They last quite well, are not stupidly expensive and do not add to a lot of road noise. I swap the front and backs every 5-6000 miles as well.

[XCnewbie]

Thanks for all the suggestions, and everyone's favourite brand and tread. On other 2wd rear-driven cars I'm a Continental & Falken purchaser. I guess I didn't add:

e) junk the fronts and replace with decent tyes, replace rears eventually.
f) get all 4 done, not STRs

The technical bulletin covers P1 and (I assume early) P2 XC70s contains the following:

Replacing the tires
When tire replacement is necessary, Volvo strongly recommends
replacing all four tires at the same time with
identical tires as explained above. Failure to do so can
result in circumference differences that may damage the
transmission and all wheel drive system.
If only one or two tires are replaced, the new tire(s)
must be identical to the tires with which the car was
built, and must be mounted on the FRONT AXLE ONLY!
Failure to do this may damage the transmission and all
wheel drive system.

Although from what I've read on these forums, the pre-2000 P1 vehicles were viscous coupled and very fussy on tyres. The P2 to about 2004 were still fussy but not as much. Only the later 2004 ones were clear of the problem as they used a different AWD mechanism. Which is why I posted. Someone may had long term use of different brands front to back with no ill effects.

If I was finding a consensus amongst advice here I'd say part worn STRs is OK with care (c), new fronts of different brands are OK (e), new all round (f) is best (but Volvo would go tut-tut). Choice (a) - 4 new STRs, is what Volvo would like you to have (but no one here agrees). Choices (b) and (d) are no go-ers.

[jgjones095]

For what its worth just bought 4 str's for my v70xc ph2 2000 tyres sre 85 on tyreleader each+ fitting. Ended up buying local for £100 a corner as i needed them and couldn't wait for delivery!
When I bought the car a year ago it needed two front tyres and after 5k miles needed new boots again. Being aware of the awd and tyre issue I plumped for all 4.
I didn't hve any issues during the odd size tyre phase though and hoowfully no lasting damage