restarting

 

It all depends on the brand/model tire, not just the numbers you site.
What brands were those tires? Once you know that, then you find out
the real diameters, and compare them. Big differences will cause faults
and blow up your viscous transfer unit.

See my answer in your other very similar thread:

The only hard 'data' is at the tirerack site, in the spec sheets, based on the
brand/model tire. If you want anecdotes, others can say what tires (brand, model,
and size) they run. You have to ignore anyone who says anything like '335/30/18
rear - 245/40/18 front works' because that could work or not work depending on
the brand/model of tire.

 

restarting

 

What do you mean by data? I offered one definition, which is the actual running diameters
of the tires. That will define whether you get faults or trash your viscous coupler. What is
your definition of data? In another thread I actually recommended two sets of specific tires
(brand/model/sizes) for your 19" wheels, after verifying that their diameters were very close,
as we/you need them.
So, what do you mean by 'data'?

You said "335/30/18 rear - 245/40/18 front, no faults"

That's not data yet. What brand/model tire? A quick look
at the tirerack site shows that their 335/30/18 tires
range between diameters of 25.6" and 26.1". Their
245/40/18 tires have a similar range (though not with
the same brands/differences as the 335/30 tires).
So, if you just buy tires according to "335/30/18 rear -
245/40/18 front" and get a worse-case difference,
you might get a huge problem.

I am tying to help you. If you ask about a given size+brand+model
we can see whether it should work, or risk damage to your car.

 

restarting

 

sorry I could not be of help. Good luck.

 

TTJunkie get a grip! He was not trashing your thread! Just trying to help you!