You are assuming that the damage was exclusively to the splines. It was quoted as damage to the transfer case. I would expect that to be internal, not the splines. I should have said that there has also been damage reported to the splines, I was not suggesting that they are the only failure point. I can still see the potential for damage to the tranfer case internals due to constant relative motion, just the same as a differential experiences.

The OPs isnt and as its his thread. Your comments about putting tyres on the front or rear aren`t relevant and who says most are 3.0is have 17 inch wheels . Mine hasnt and thats the way it came from the factory. 2.55 x19 fronts and 2.85x19 rears.

The OP doesn't have staggered tires, so it is relevant. Note his location in the US.

75% of E53 models were the base 3.0 in North America, which was the largest market for X5s. BMW published sales figures every month. There was a sports option with 18" tires, but they weren't staggered. On the 4.4 there was also a sports option with 18" as I recall, and a separate 19" staggered option (depending on model year).

Yours is an exception, being in the UK. Given the price of the vehicle there, BMW put the most expensive tires they offered on it.

Since there is differing opinion here, I decided to talk to the guys at the local dealership. They were nice enough to give me a tire gauge to take home with me since I had my 540i on me at the time. They told me that they feel comfortable with 4/32nds of an inch difference between front and rear tires max. The difference for me was 5/32nds so I have decided to go ahead and replace the fronts. It may end up being overkill, but I guess I'm too damn anal and overcautious to just look the other way on this one. I'll spend the extra $350 for peace of mind.

Thanks for all your input guys!

It isn't irrelevant at all. People with staggered setups can still choose to only replace two tires at a time. Due to the fact the fronts and rears typically don't wear at the same rate, they could easily end up in a situation where they have new rubber on the front and worn rubber on the rears.

Nothing wrong with that.

You aught to learn to read the thread properly . It was talk about switching tyres from front to back that I said was irrelevant. Not just changing fronts only or rears only.
With a staggered set up the fronts stay on the front and the rears stay on the rear. Therefore talking about putting the new tyres on the front and the old on the rear is irrelevant if you only need rears.

:rofl: ass.

You aught to take your own advice. As JCL said, most of the e53's sold here were non-staggered setups, where moving tires from front to rear or Vice Versa is possible, so your post about it being irrelevant due to the fact most X5's came with staggered setups was completely inaccurate. I also included those videos just to show what can happen with worn tires on the rear and new tires on the front, not necessarily moving worn tires from front to rear or rear to front. Once again, I was also trying to show people with staggered setups that they may want to consider going with 4 tires if they have a staggered setup instead of getting themselves into a situation where they end up with new rubber on the fronts and fairly worn rubber on the rears. This is a very possible scenario if you just replace two at a time.

You ought to use the correct word, or it will all be for naught.

Yea JCL had already answered with a relevant response . Didnt need any help from you . Some tossers just cant help but interfering though