Harry,
This reply is to you but it is really to all who have responded, or maybe read this thread with interest (and certainly to the original poster). Thanks to everyone's replies, and a little googling, and considering the intended usage of my tractor, and pondering the nerve-wracking job I just did bush hogging my 7 acre steep hill (my first time on a tractor), and talking to a confidence-inspiring manufacturer of spacers (the gist - no complaints, no spacer failures over 20 plus years), I have decided to space all four wheels on my new Kioti DKSE 40 hydrostatic tractor. I'm going to buy 4 inch spacers all around and preserve the geometry of the factory wheels - and go for maximum stability. I thought it might be helpful to other tractor owners to recap why I decided to go with spacers.
One salient thing about my new tractor and its anticipated use is low utilization. The front end loader can lift 2,740 pounds, but I can easily limit the load to half that or less when I occasionally have use for it. I'm mostly going to bush hog my own 8 hilly acres about four, maybe five times a year and do light landscaping work once in a while. So hopefully whatever asymmetric stresses I might be putting on the axle and/or wheel bearings with spacers which might lead to premature wear or failure, compared to the Kioti vertically designed stresses which are supposed to load the outside and the inside of the bearings equally, will never rise to the wear level of a tractor designed to be used frequently - or in commercial applications. Harry, your explanation about wheel bearings was much appreciated, and since you didn't mention concerns about axles with spacers (except for indirectly with the sea story about the modified dual axle failure of the combine) I am assuming whatever affect spacers might have on axles is relatively minor. A few posters think the axles, particularly the front axles which turn and experience side loads, and particularly front axles with front end loaders, are stressed with spacers, but as a residential user I can keep FEL loads reasonable.
So the reality is that the bearings for both front and rear wheels are additionally stressed by wheel spacers, but the question is how much and will it actually result in premature wear and/or failure? You pointed out that bearings are designed for both a vertical design load of the tractor's weight and side loads from slopes and turning. There is some ideal perfectly vertical load right down into the center of the bearing, and some design strength for what side loads will do in terms of distributing the load to the inside and outside areas of the bearing for slopes and during turning. For all our tractors, the engineers must have thought about a range of inside and outside wheel bearing load tolerances because the tractor wheels can be constructed and mounted within operator manual settings that change the wheel/tire width a number of ways within about ten inches. With my rear wheels alreadly constructed for maximum width, adding spacers is going to reallocate the load on the bearings from more or less a vertical loading within this design tolerance range to a permanent (as long as the spacers are installed) asymmetric load. Which may or may not be inside where the Kioti engineers concluded bearing wear is acceptable! But additional asymmetric bearing loads will be applied by my constantly driving the tractor uneven terrain, sometimes across side hills - and those bearing loads to my layman's mind would seem to be more than any spacer on level ground would reallocate on the bearings. So in the real world there will be additive loads - and, importantly, canceling loads - applied to my bearings as the tractor moves. I'm going to proceed on the thought that we're probably talking about a cumulative additive/subtractive bearing/axle wear effect on both front and rear wheel bearings, again given my planned underutilization of a workhorse tractor, which will not manifest itself for decades. I'll be watching for leaks and investigating any suspicious signs of premature failure.
One poster made a point that is an important one. He said he can't see all the bolts once the spacers are installed so he locktites them. I've been cautioned that tractor wheel bolts can loosen with use and they need to be checked often. The company I'm considering buying the spacers from does provide locking washers. This is something I'll have to keep in mind.
Lastly, what about corrosion? Should the spacers be painted or left alone? What is the cost of anodizing - and does that prevent corrosion? The answer I got from the manufacturer is that the high grade aluminum blocks they begin with to shape their spacers don't corrode appreciably. One poster spray painted his spacers a matching gray color. Anodizing doesn't cost much - just a few dollars per spacer - and is a dipping process that doesn't affect bored tolerances. This from Wikipedia on anodizing, "The process is called "anodizing" because the part to be treated forms the anode electrode of an electrical circuit. Anodizing increases corrosion resistance and wear resistance, and provides better adhesion for paint primers and glues than does bare metal." So anodizing will be something I'll pay for when I order the spacers next week - probably black for low glare off the spacers - and ease of seeing any deep scratches from my clumsy driving *grin*.
On the downside if I install these I may void all, or more likely part, of my new tractor warranty. It would only be fair that if I do mess up the axles or bearings I pay for the repair, not Kioti.
As many of you have long concluded, enhancing the stability of these tractors on hillsides is worth the risk of premature wheel bearing wear, which seems to be the most valid concern. With my hills, my inexperience, and my wife wanting to bush hog...spacers it is! Thanks again to all who commented.
Would anyone like me to upload before and after photos? It will be a few weeks, maybe even a couple of months, before I have the spacers in hand and installed.
Best,
Rhino
