Wow, I read most of the prior posts, and despite my clearly belonging in the
"non-math" ability crowd, I'm pretty sure that my confidence level is far below that of any max spec on any equipment.
I'm trying to avoid using my Gravely to mow the slopes because it will only cut at around six inches, and I'm trying to mow the rest at eight.
I am putting in a large garden on this farm, owned by a close friend. The sloping area isn't far from the flatter level where the garden is, and yesterday I needed to mow the area around the garden. So while I was mowing I was looking over at the sloped area, shaped like half a bowl, (for us old farts, would make a nice mini-Woodstock...) and the answer was really easy. It will only take me about an hour at most to mow the hill with the smaller machine, so I realized at least for me the issue is moot, just be safe and use the Gravely. I'll experiment by running the tractor along the slope to see where my comfort level leaves me, likely pretty low. My tractor is due back from the shop with a new Michigan suspension seat from Northern Tools installed, and I'm hoping that will hold me in place better, as well as being seriously more comfortable overall. So I don't think I"ll slide too much in this seat, but then, I don't want to...
I don't want to hang on for "dear life" and I know with the big R1 tires I've got, they may not lose traction gradually on a slope.
And I found some pics I took to illustrate why even shallow slopes can be super dangerous if the ground gives out underneath you. My retired doctor friend was very lucky to crawl out from the bottom of his pond, and I do mean crawl with many broken bones including his back. Do not do this at home...
Ultimately nothing beats safety. The problem really arises when one can't afford that super expensive slope mower, and tries to make do, as most of us do, with what one has. Run what you brung. Just have to do it safely, and know when to revert back to walk behinds and even a string trimmer.