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Post by alf on Aug 8, 2019 15:01:17 GMT
Hmm, all sounds quite complicated! On the original question, I was always of the opinion (partly from the manuals of Subarus, and the Passat 4WD I had, which was an old A6 full time 4WD chassis) that with full time 4WD you should make sure you use the same brand/size of tyre, and ideally replace all of them at once, but matching the types is more essential than the tread depths. As I've mentioned before, different tyre types allegedly of the same size actually vary in size a lot. With Haldex/part time systems it does not seem to matter - the Q3 originally had PS4 on the back and Avon ZZ3 on the front and neither the handbook nor the garage seemed to care.
If people like BMW main dealers are suggesting that tyre wear differences can wreck parts of the transmission then I'm smelling two things - bullshit, and/or design not fit for purpose. With the ranges of wheels/tyres on offer and especially a staggered setup of wider rears, there must surely be rolling circumference differences from the factory on many of them. And the car can't be designed to not deal with uneven wear, surely? If (inevitable) uneven wear wrecks the car, in my book it was not fit to leave the factory. Just how constantly matched do they expect the tread depths to be? What a load of BS.
Then there is the question of pressures - people rarely check them much, differences in pressures can affect rolling resistance more than tyre type/tread depth. If you buy your cars second hand and put decent miles on them - like me - this is a potential concern around anything full time 4WD, it could mean seriously expensive bills if the previous owners have not treated the car perfectly.
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Post by Tim on Aug 8, 2019 15:18:48 GMT
ALF, my car had Goodyear F1 Assymetrics all round, the fronts were changed first last time but the rears were done shortly thereafter as I hit a massive pothole and damaged both left hand tyres (when the fronts were 4 days old  ). This time round the fronts got replaced about 1-2k miles before the transfer box issue came up. The BMW dealer quoted me £4,500 to fix it including 2 new rear tyres! In light of a separate £6k trade-in offer I reckon that means the car is technically a write-off! Its currently at a BMW specialist in Aberdeen to get repaired. Just to add to my worries my brother in law - who did a lot of research on this due to owning an X5 40d - said that he thinks the tyres need to be BMW star rated to avoid the issue although I think that may be more warranty cover related than real. That really does sound like bullshit to me but with the possibility of financial doom if I get it wrong it adds to the stress. I'll certainly not be buying an xDrive ever again if the system is so sensitive that it can't cope with a few mm difference in tread depth - it's not as if the roads are perfectly smooth is it! |
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Post by Martin on Aug 8, 2019 15:22:36 GMT
I think the BMW star rating will be related to the warranty, but based on how sensitive your car seems to be, who knows?!
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Post by ChrisM on Aug 8, 2019 18:25:33 GMT
I'll certainly not be buying an xDrive ever again if the system is so sensitive that it can't cope with a few mm difference in tread depth - it's not as if the roads are perfectly smooth is it! Does this mean I should definitely forget an X1 xDrive? |
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Post by Roadsterstu on Aug 8, 2019 20:25:04 GMT
I'll certainly not be buying an xDrive ever again if the system is so sensitive that it can't cope with a few mm difference in tread depth - it's not as if the roads are perfectly smooth is it! Does this mean I should definitely forget an X1 xDrive? I'd say it depends how long you plan to keep it. First or second owners may never experience the issues but further down the line, as with the V60, problems can happen. |
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Post by Tim on Aug 9, 2019 8:10:11 GMT
Does this mean I should definitely forget an X1 xDrive? I'd say it depends how long you plan to keep it. First or second owners may never experience the issues but further down the line, as with the V60, problems can happen. Quite. My 3 series had the problem at 112k miles. The set of tyres replaced have been on the car for around 35k miles (well, the fronts have, the rears are still on there with 3mm left). It depends what your mileage is Chris but I'd guess you're unlikely to break it for at least 3 years! |
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Post by racingteatray on Aug 9, 2019 9:32:29 GMT
Indeed.
If it was a major issue, BMW and others wouldn't sell as many 4wd vehicles as they do.
I can't remember the last time I had to buy a new set of tyres (other than winter tyres) owing to wear. Partly that's due to using winter tyres in winter, but of the three new BMWs I've bought since 2009, the first two were still on their original rubber when I sold them and the GC's set are still only lightly worn after 2.5yrs.
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Post by bryan on Aug 9, 2019 9:43:46 GMT
I hadn't realised until I had the Merc tyres changed (due to bulges rather than tread wear) that the OE tyres are a better wearing compound than the equivalent replacements you can buy!
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Post by Bob Sacamano v2.0 on Aug 9, 2019 10:15:10 GMT
BMW have sold X-Drive models in the most litigious market in the world, the US, for over 10 years. I'd be surprised if there was a major issue that affected large numbers of vehicles without there being some sort of class action over there.
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Post by Tim on Aug 9, 2019 10:45:10 GMT
It does appear to be quite a common issue but from looking online a lot seem to happen in the warranty period.
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