Replacing just the rear tires ok?

[Sundayjumper]

Originally Posted by JCL

...I do think that a constant speed difference between front and rear contributes to transfer case wear.

Wear to the planetary gears, yes, quite possibly, but that's a different matter.

Originally Posted by JCL

BMW techs on the board have commented that they have seen damage to transfer cases from tire size differentials.

Commonality is not causality These propshaft splines are known to fail anyway, how anyone can claim it's definitely due to tyre size in some cases, but not in others I don't really know. From an engineering point of view, a small difference in tyre size front-rear will have absolutely no significant effect on the loading on this spline. IMO far more likely is a different connection - that the kind of person who fits huge blingy wheels is probably the same kind of person who drives their car hard, doing full-bore launches more often. That will shorten the drivetrain's lifespan a lot more quickly than having slightly different tyre sizes !

Originally Posted by JCL

I have personally only seen DSC errors due to the difference in rotational speeds.

Same here.