Step 3: Steering system
The next step is one of the most important of the build. Many people go out on the track with the stock steering setup. That's a big mistake for a number of reasons. For one, the stock components aren't made for going 50MPH, as is none of the other stock components. Secondly, there's more to steering besides making the wheels turn. You also need to have the proper caster, pitch, and turning radius so that the chassis will handle corners better.
Most mowers come with a gear driven steering setup. These are worthless and tend to pop out of place. So you'll need to make a "direct steering" system. In other words, a solid connection between the steering wheel and the front wheels.
For this build, I bought a pre-built front axle from a guy in Texas. He has a small business called " Acme mowersports" and can be found at www.acmemowersports.com. His front axles are a good deal because even if you were to build your own, the cost would be only slightly less. With the Acme axle, the proper caster and degree of inclination are already built-in, which will save you lots of time. These come with the radius arms as well as connections for the steering axle, which on mine runs down the center of the front of the mower over the top of the engine.
Next up is the installation of the steering shaft running along the front of the frame. This mower has an unusual setup where the steering linkage runs over the top of the engine. An a arm runs from the steering wheel pitman arm to a shaft running down the front of the frame to the radius arms of the front axle spindles. First, I got some 1/1/4" steel pipe and cut some lengths about 2" long. On each end, I placed a bearing in which the steering shaft fits through.
The top of the front steering shaft has a removable lever to attach the piece of linkage coming from the steering wheel. This enables you to remove it if needed. If you look at the pic entitled "pitman arm detail", this is the steering wheel shaft with the pitman arm welded on. As you can see, the arm on the end is rounded and has three holes. There's a reason for this, which is to prevent the heim joints, which are the screw-on ball bearing pieces on the ends of the rods from binding. The reason for the three holes is to give you adjustments to the steering sensitivity. Further out gives you more slack. Further in tighter. It is also important that the arm running across the top of the engine area has threads on either end. This way the heim joints can be screwed in or out to adjust the amount of right and left turn in the wheels.
In The pic entitled: "Steering arm", you can see how this system works together. Lastly, the "turn right" pic shows the underside linkage and radius arms. If you see the "t" shaped piece, that's where the radius arms connect. The "T" is welded to the bottom of the front steering shaft.
Another step is to determine the angle of the wheels. Generally, it is better to have the left wheel turn in more than the right. I usually have the left wheel turn in @ 10:00 and the right at 2:00.
Lastly, you will need to install what are known as "stops", which are basically welded on rods or bolts to prevent the wheels from turning too far. If they turn too far, the steering wheel will turn completely over, thus reversing your steering! Not good! For this build,. all I did was weld two 5/16" pieces of steel rod to the front of the axle, right where the spindles swing in and out. The spindle arms simply hit the stops. I held the wheels in place at the correct position and placed the stops at exactly where the spindle arms hit, then welded them into place.
Once you have the steering done, then you've just completed one of the hardest steps!