Unfortunately, it looks like the pictures are all from an RT. I can't see how it should work on my F3!
Those pictured should work fine on the F3 Ltd's & F3-T's jneg, cos they have the same swing arms as the RT's

. But it still shouldn't be
too hard to fabricate something similar to suit the rounded tubes of
your F3's swing arm, even if you need to show those pics to a metal shop/home metal worker friend if you aren't up to doing that yourself. :dontknow:
Still'n all, I do a lot of back country miles on my Spyder, and I really don't 'actively avoid' gravel or dirt roads; plus, I'll even admit that there just may have been the odd occasion when I've gone
searching for a 'loosely gravelled road/track' just to play around a little bit (go on, try it, it can be fun! :thumbup: ) - and with
lots of gravel road miles & even some 'spirited playing' on them, I've
never had any stone/belt issues as a result!

hyea: So maybe there's a lot of needless angst over riding on good gravel or dirt roads?! :dontknow:
Fresh & still loose/sticky chip seal covered roads however.... :shocked: those & that stuff I
DO actively avoid whenever possible!! :gaah: . That stuff is
EVIL & should be
banned - or at the very least any road authority/municipality that uses it should be forced to
immediately & without question pay full compensation for any distress, damage, &/or clean-up resulting from riding/driving on it! :cus: :banghead:
