imho : Safe to use if under 1/4" diameter on any application that has a 1/4" grade 8 or 12.8 metric bolt because what it is holding together will usually shear or pull out before the stainless steel fastener gives up.
That being said, I stock and use everything from #10-28 to 3/8" stainless repairing OPE and trucks. Mostly bought off Amazon.
No, I am not going to use a 3/8" or 1/2" stainless to remount a spring hanger, TTB radius arm on a truck, or a shock mount. I AM going to use it on cutting decks, consoles, stake holders, roll bars (aka light bars) etc.
I lost a 4x8 trailer into a big hole when a tree uprooted, the bolts (3/8 stainless) and frame held, what gave out? Not the pressure treated 2x4, not the 3/8" stainless bolts, it was the stake holders that twisted.
When I worked for Ryder truck (tractor trailer) part of my job as a mechanic was removing all unmarked or grade 5 fasteners and replacing them with grade 8 for the mudflaps in boxes at that location while I was testing for my federal license.
I would never use stainless in that situation, thousands of constant high load shock and vibration where a loss means a potential accident or fatality ... to a bus load of nuns.
In my much younger days, I worked on and off doing engine work to boats a few times (old school V-8s). Binimi tops are secured with stainless to many times plain steel or aluminium , but, you would be hard pressed to find stainless in the engine compartment of a cruiser.
Nope, cast steel (or iron?) exhaust fastened with carbon steel grade 5 or grade 8 bolts. Even with water running through them. Not even the water pump impellers were held on with stainless steel.
So, it comes down to common sense and location, location, location
Today I was changing wheels (bought on Amazon) attached to hubs I bought from Amazon:
DRIVE UP EZGO TXT Front Hubs, Golf Cart Front Wheel Hub with Wheel Bearings Assembly Fits EZGO TXT Medalist 2001-2013 Gas and Electric Golf Carts, 70895G01
https://www.amazon.com/dp/B08DKTTGK3
Aluminium hub, stainless steel bolts, with steel acorn nuts.
Someone correct me if I am wrong, but, I think these are standard clone replacements and if stainless steel with aluminium and steel was a death sentence, would Club Car and E-Z-Go be using that combo?
If you need an upgrade in anti-seize beyond the grey stuff, marine might be a good pick.
https://boltdepot.com/MRO_solutions_...ade_anti-seize
Yes, in an industrial setting having stainless with steel or aluminium while being exposed to chlorine might be a bad idea.
But, the engineer that earns over $150 per hour is going to have all that figured out before you come along.
It is a used, under $2000, lawn or garden tractor, I would not over think it. Use what makes you happiest, especially if you might have to repair it again in the future.
Aluminium rivets on a steel deck might be a problem, but, might the fix to a neighbour's cutting deck using license plates (aluminium plates, aluminium rivets, steel deck, no anti-seize) far out lasted the Kawasaki 22 HP engine he blew up by running it out of oil.
