How much force should you have to apply on a pan to release the dog ?
Do you keep it light, or heavy?

I notice as my traps get rusty, the pan tightens up, and is more difficult to move..
Even without the dog set, the pans can be difficult to move.

Isn't it better to have a hair trigger? Rather than a direct force of a 15 lb animal on it.

A hair trigger will result in toe catches in my opinion. I want the pan tension set up enough that the foot will go down with the pan. Will be a much better catch. I'm talking about coyote traps, I was assuming thats what you were referring to.

I want pan tension for everything but rats and mink ! But your gonna get a lot of different opinions on this .

Depends on what your trapping. After saying that I have caught Coon,Coyote, Fox, Fisher, Opossum, Skunk with PIT pan system that gives 3-4 lbs. of pan tension. Heavy pan tension IMO leads to less toe catches.

I'd run more pan tension if I was having an issue with toe catches but I don't so I run very light pan tension.

So, with heavy pan tension the criter stands on the pan and it does not fire the trap. That is the long and short of it, set the pan tension so that it will not catch what you don't want. 2# will keep out squirrels 5# will keep out most foxes and 12# would probably keep out small coyotes.
Toe catches are the result of poor foot placement and nothing else.

You can easily test this, human reflexes are faster than animal reflexes- so set two traps, one with low tension and one with high tension- then press the pan on each with your index finger until it moves down (this would be the point that a criter could be warned) and just as the pan moves off the dog jerk back as fast as you can; you will see that the heavy tension pan catches you, but you can always escape the light tension pan???? eh?

The thing you talk about of the pan tension increasing with rust is just rust sticking to rust, that is the reason for using tannin and paraffin to remove and prevent rust. i have traps that have lain out in my yard for three years right now, that will work quite well, just because they were once treated with tannin and paraffin.
But it could also be somewhat a problem with poor fit between the pan shank and the pan posts, if the posts look like / \ or \ / rather than like l l , they will need bending and probably a washer inserted next to the pan shank so that the pan screw exerts an even force, rather than a pinch at the top or bottom.

Make them step down into the set, and use whatever pan tension you want. By the time they step down into the pattern, they have committed.

X2

I run roughly around 2.5 lbs on my traps I have a mix of duke round jaw and bridger dogless #2 and 3 mb 550's all 2 coil. I have had a couple of toe catches this year but the crap weather we've had and even with wax dirt the traps have had to fire through less than ideal conditions. But either way its still a catch
J

I suspect light pan tension can cause toe catches but I doubt it's the only thing. I would think that if part of the animal's foot is on the jaws or levers when the trap fires then a toe catch could easily happen.

I have a few 550 but mostly run Bridger #3 with some Montana #3. I rarely have toes catches in the #3s (bridgers set with just enough tension that pan will hold itself up and Montana just however they come out of factory) but it's not uncommon to get toe catches in the 550. Just my experience.

Pan size has as much to do with toe catches as pan tension. Maybe more. If your target animal can put his foot on the jaw and the pan at the same time, that's most likely a toe catch.
I run 3 on fox and 6 on yotes with an 1/8" pan drop at the end of the pan.
No toe catches this year. But I did catch a rock lol
Just what works for me