Mixed Tires
 

My 4.4i X5 currently has Yokohama Advan ST tires, with 275/40R20 on the front and 315/35R20 on the rear.

My front tires have about 4mm tread, but have worn badly on the outsides, the left front now having a bald strip about 4 cm wide.

However the rear tires are fine, about 5mm even tread on them.

I have found a good deal on some Hankook Ventus RH06 tires for the front, however I am wondering if there is a downside to having different brand tires on the front and rear? The Hankook tires are MUCH cheaper than the Yokohamas, and all the reviews I have read show they will perform nearly as well.

We don't really get snow on the roads here in New Zealand, so we generally run the same tires all year around.

since it's an AWD vehicle, I assume having 4 tires of the same age and traction is much more advisable... my perception...

Treat your baby right and change all of her shoes + balance and alignment;)

Agreed! Don't mix and match :)

you'll change the dynamics of the tire. wet handling, dry handling, wet braking, dry braking, hydroplane resistance....

don't be surprised to find the vehicle change characteristics, becoming much more unpredictable. I do not recommend it

And the most important factor in pre-facelift X5 tires are to have the same rolling diameter. Tirerack has that in their info listings on the tires. If the front and rear tires are different in rolling diameters it puts extra stress on the transfer case, especially the front output shaft.

How do you avoid this problem when the tires wear at different rates? And with a staggered setup, the rear tires are not the exact same rolling diameter anyway are they?

Dont do it, just match them up properly.

Ok I just talked to my local BMW shop service manager, and he said that even with the older E53, there is no need to replace all 4 tires at once, and that it is actually quite common to replace the fronts before the rears, especially for people with "spirited" driving styles. He said ALWAYS replace left and right at the same time though.

As for mixed brands, he said it is defintely better to use the same brand / model of tire, but if you do change, try and go for a tire in the same performance category and load rating.

:iagree:

IMO it isn't a big deal to mix tires as long as they are the same on each axle. There is often more difference between two of the same tires with different pressures than between two tires worn different amounts. If you notice a handling difference due to very different tire characteristics, deal with it then.