I look at it as an endless cycle. More tire , more gear, more motor. You should not have any driveline failures. You should always need one of the things in the endless cycle. If you have enough motor and gear to turn the tires , Then you need more tire. If you can't turn the tires , then you need more gear or motor. And it just keeps going and going. I use the three strikes rule. A part that breaks on me three times is getting upgraded, No Exceptions !!! Guys in our Mudbog club that are kind of on a budgit use the tires as a weak link. They run a big tire that is about 75% wore out . That gives them some traction, alot of wheel speed , but very few driveline failures. M1028