I went from OE Michelin DIAMARIS to LATITUDE TOUR HP back to MICHELIN DIAMARIS.

Feedback: LOVED the quiet ride of the Latitudes, handling is 80%-90% same, less turn in due to softer sidewalls. No longer made in 315/R20 sizes, hence my change back again.
Moving back the results are LOTS of road noise when compared to the Latitudes. Harder sidewalls mean more road feel but you gain handling. It is a trade off max-handling vs ride and comfort. Normal for big fat BMW's.

Now that Diamaris is no long made in sizes to fit a X5 4.6/4.8is, then there is only one choice:

Pilot® Sport All Season 4 Tires if you want to stay with Michelin tires.

The real challenge is keeping the tire pressure low in the rear to not have accelerated center tire wear but high enough to keep the beast planted on turns and hard runs. Everyone with different tire sizes will now chip in their own pressure /tire wear stories. The 4.6 and 4.8is rear 315/R20's are a beast sized tire and come with their own challenges. I have gotten 12K out of the rears but with proper care I should have gotten 18K. Most report 10K to 15K tire life. Fronts will go for 2X. Welcome to 5,000LBS of BMW wearing tennis shoes thinking its a Sport Activity Vehicle vs a SUV.

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2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green