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Step 13Update the old Steering system to a fully adjustable one.
Steering.
Perhaps the single most important thing you can do for a racing mower is get your steering right. Before I go into the build, let's talk a little about steering geometry because if you understand how it works, you'll have a much easier time building one. I have to admit it took me a long time to figure it out. The guys I race with in many cases raced stock cars thus they have it down to a science.
Basically the problem that we have on the track is that the rear axle doesn't have a differential. As such both rear wheels are traveling at exactly the same rate. With a differential the outer wheel naturally travels more than the inner, thus making turning into a corner easier. In order to correct this problem, you'll want to remove weight from the front right and place that weight onto the front left so that weight is removed from the right rear. In doing so you'll offset the effects of having no differential. This is done so by adjusting three things: Caster ( the angle that the spindle sits- either positive or negative, the Camber- the angle at which the wheels lean in or away from the mower, and toe out- as in how much the wheels point away from the mower. We'll go into this later when final adjustments are made.
The old spindles were cut off of the front axle. I re-used the old axle instead of installing a new one. The new spindles are fully removable from the axle and are mounted with large heim joints. The mounting plates for the spindles are welded to the ends of the axle and have machined slots so that the spindles can be turned forward or back ( which gives you your caster adjustment). These plates need to be welded to the ends of the axle at a 10 degree angle with the tops of the plates pointing in towards the mower. This is critical because this in turn gives you your camber- or the degree in which your wheels will lean in towards the mower. Having this adjustment will allow you to carefully adjust the camber in such a way as to help push more weight onto the left front wheel meaning you will be able to "hook up" more easily in the turns.
With the mounting plates welded in place, the spindles could be attached. These spindles come in a kit and you can get them from various go-cart suppliers. Some people make their own spindles using bolts. If you do that make sure to use Grade 8 bolts as they are less prone to bend than conventional bolts.
The last major thing you'll have to do is to attach the spindle arms for attaching the radius rods. There's a pretty simple method for doing this: With both spindles absolutely straight on both sides, attach a piece of string from the ends of the spindle mounting bolts and attach the string to the center of the rear axle. Weld the spindle arms as if you are lining them up with the path of the string. Easy enough.
Once the steering system is installed, you'll have to do some adjustments to the setup to ensure the mower is handling properly. But that will come later once the machine is completed.
Perhaps the single most important thing you can do for a racing mower is get your steering right. Before I go into the build, let's talk a little about steering geometry because if you understand how it works, you'll have a much easier time building one. I have to admit it took me a long time to figure it out. The guys I race with in many cases raced stock cars thus they have it down to a science.
Basically the problem that we have on the track is that the rear axle doesn't have a differential. As such both rear wheels are traveling at exactly the same rate. With a differential the outer wheel naturally travels more than the inner, thus making turning into a corner easier. In order to correct this problem, you'll want to remove weight from the front right and place that weight onto the front left so that weight is removed from the right rear. In doing so you'll offset the effects of having no differential. This is done so by adjusting three things: Caster ( the angle that the spindle sits- either positive or negative, the Camber- the angle at which the wheels lean in or away from the mower, and toe out- as in how much the wheels point away from the mower. We'll go into this later when final adjustments are made.
The old spindles were cut off of the front axle. I re-used the old axle instead of installing a new one. The new spindles are fully removable from the axle and are mounted with large heim joints. The mounting plates for the spindles are welded to the ends of the axle and have machined slots so that the spindles can be turned forward or back ( which gives you your caster adjustment). These plates need to be welded to the ends of the axle at a 10 degree angle with the tops of the plates pointing in towards the mower. This is critical because this in turn gives you your camber- or the degree in which your wheels will lean in towards the mower. Having this adjustment will allow you to carefully adjust the camber in such a way as to help push more weight onto the left front wheel meaning you will be able to "hook up" more easily in the turns.
With the mounting plates welded in place, the spindles could be attached. These spindles come in a kit and you can get them from various go-cart suppliers. Some people make their own spindles using bolts. If you do that make sure to use Grade 8 bolts as they are less prone to bend than conventional bolts.
The last major thing you'll have to do is to attach the spindle arms for attaching the radius rods. There's a pretty simple method for doing this: With both spindles absolutely straight on both sides, attach a piece of string from the ends of the spindle mounting bolts and attach the string to the center of the rear axle. Weld the spindle arms as if you are lining them up with the path of the string. Easy enough.
Once the steering system is installed, you'll have to do some adjustments to the setup to ensure the mower is handling properly. But that will come later once the machine is completed.
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Aug 22, 2011. 1:08 AMMcClellan41
says:
i was goin to do this to mine but never did and now wish i had!!! but might have to down the road!!
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