Tiger vs SU-85

Is it better to keep a Tiger at max SU-85 range and let SU-85 shoot it (I think it does less damage that way) and flank with something else to destroy the SU-85; or have the Tiger join the fight and shoot the SU-85 itself? Say I have a PaK to shoot at the SU-85, which of these scenarios ends with less damage on the tiger? Or is there a better way I didn't think of?

It's hard to understand exactly what your asking here.

Tiger's aren't actually the best unit to use against an SU-85. They're main attribute in this kind of fight is that they can take a lot of damage. So you probably want your Tiger up front "tanking" the damage while other units support, be they paks, shrecks or other tanks.

Charging in can be risky (mines, button) but leaving the Tiger under attack isn't a good solution either. The Su-85 doesn't really do any less damage at long range either, it just misses a bit more. However, I wouldn't count on having many shots miss in an engagement with a Su-85 against the giant (target size) Tiger, especially when static.
If he'd get into the range of your Pak, he could also just reverse away so that wouldn't work well either.

You could do a mid range (less danger of AT grenades/mines/button) flank with the Tiger and some infantry to make the Su-85 turn. Because you are at mid range and not rushing in cosely (yet), he likely won't just reverse away. Once he starts turning and pulls his infantry towards the Tiger you can start pushing your Pak into range because he won't see it that easily this way.
He is then surrounded by the Tiger and infantry on one side and the Pak (and a little infantry) on the other side. He still has one direction open to retreat but maybe you can get him with a Panzerfaust from the Pak-side or completely flank with the Tiger (be careful of mines and other units!).

One thing to keep in mind though is that he will not just have one Su-85. The high fuel and CP cost for the Tiger means that you'll either fight two of them (unless you already killed one) or maybe he has only one and an artillery piece (can hamper the infantry flank or the Pak).

Is it better to keep a Tiger at max SU-85 range and let SU-85 shoot it (I think it does less damage that way) and flank with something else to destroy the SU-85; or have the Tiger join the fight and shoot the SU-85 itself? Say I have a PaK to shoot at the SU-85, which of these scenarios ends with less damage on the tiger? Or is there a better way I didn't think of?

I can defeat a su85 wt my p4 only..just go arnd him