Harry and All,
I just poked around the internet looking for more information about wheel bearings. I found several car forums where the subject was discussed. As SD and others pointed out widening the front tires, which steer, is more problematic. For cars effects can range from tire scrub to loss of traction to larger turning radius' to the bumps in the road translating into steering wheel twitchiness. I would think that most of these effects would be lessened by the slow speeds of tractors, but then again my manual is full of cautions about going fast on pavement and turning sharply. I think it wise to leave the front tires stock, but I am still interested in the question of the rears. All the articles agree with you that there is increased stress, wear and likely premature failure of the wheel bearings if you add spacers. The question is over what time frame? We measure our tractor use in hours. And what is the cost of buying new rear wheel bearings versus the benefit of greater stability and safety on hillsides? I found an article on how to detect wheel bearing wear, but the bottom line is it can be hard to see as wear is measured in very small units. For fast moving machinery where heat buildup might lead to catastrophic failure an in-service failure would be bad. For our slow moving rear tractor wheels an imminent bearing failure might be squealing, or odd ride, or a drag from the less than optimal friction. Has anyone ever experienced a rear wheel bearing failure in a tractor? I wonder - could a rear tire actually fall off? That would not be good!
I found an online Kioti parts catalog that had the front wheel bearings priced at $46 each. Couldn't find the rear wheel bearings (anyone?), but I'd imagine they would be more expensive. Let's say they cost $100 each for argument's sake. Plus labor to install them, which in my case would be $75 to have the tractor taken to my dealership plus perhaps $200 labor to pull the 600 pound rear tires off and remove and replace the wheel bearings. That would be $375. Not insignificant.
The big question...how often to schedule the replacement to preclude an in the field failure? It sounds like a fair number of tractor owners have spaced their rear wheels. Any real world experience? One car forum guy noted the discussion of physics but said he'd driven over a hundred thousand miles in a ferrari at very high speeds and had not problem with the spacers he'd put on this car. Hmmmm....now there is where a catastrophic failure would be noticeable!
Thanks for any and all opinions or real world commentary.
Rhino