A-arm suspension complication

Xtreme Cartz

I tried to figure it out but simply dont get the geometry. I have a yamaha g9 golf cart with a custom 9" lift using the stock control arms moved a few inches out and several inches wider. The lift is achieved by mounting the arms lower on basically a large sub frame.
A few setup points about the suspension; I run it toe in and a slight scrub radius.
I have a big problem with bump steer, and another problem with the suspension compressing and toeing in severely while driving in reverse. My theory is that when the cart first begins to reverse, the slight toe in and scrub radius put an outward pulling force on the tires starting a snowball effect. As the suspension compresses due to the pulling force, bump steer takes place toeing the wheels in even more causing more force, more spring compression, and even more toe in.

I thought the problem would be solved by fixing the bump steer problem and adjusting toe. I changed the tie rods so that they run parallel with the arms and made the tires toe out. Now there is no more bump steer that I can feel, but the problem of suspension compressing in reverse is still there.

Help me please I have never been so confused.

BGW

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scottyb

I'll be watching this to see what I can learn....

dirtysouth

What did you do to correct the tie rod angle? You need to set your toe as close to 0 as possible. This will help with the reverse squat. Single a-arms are tricky when it comes to bump steer and camber issues. The OE shocks (Yammy) aren't stout enough to handle the oversize tires very well. I have seen folks add another OE shock per side. From what I have seen, it makes a big difference, but rides a bit stiffer. You could lengthen the steering box pitman arm, but that will speed up your steering, not a good idea on a lifted cart.

Xtreme Cartz

6" spindle risers made the tie rods run perfectly the same angle as the arms, but technically if its lifted 9" wouldn't I need to correct the tie rod angle 9"? If I were to adjust them anymore they wouldn't be parallel with the a-arms.

I will give it a try lowering the pitman arm 3" and setting the toe to 0 as you said. The other problem is it doesn't want to stay where I set the toe.

I'm running dual coil overs.
Thanks!

dirtysouth

If the you can't keep the front aligned, then the tie rod angle is off. You will have to play with this to achieve the proper angle. Take the shocks loose on one side and move the wheel up and down with the tie rod connected. You will probably see that the wheel turns in or out as the a-arm moves up and down.

Xtreme Cartz

I made a 6" pitman arm drop bracket and changed to 3" spindle risers. It's a little better now and looks identical to the factory angle. The steering is pretty much a 1:1 ratio so I'm not sure if I'll go back to 6" risers and do a 3" pitman arm drop. Also the cambers off on the driver side wheel but I think this might have something to do with the spindle nut being too loose.

dirtysouth

Yer makin' progress. Try to keep the steering risers as short as possible. The taller they are, the weaker they get.

Xtreme Cartz

Good advice! I am actually pretty happy with it right now but will need to do some more testing.

dirtysouth

Glad to hear it. It takes a little time, okay, maybe a lot of time, but it will pay off for ya.

DOOmsman

I am in over my head but have to ask, shouldn't the shocks be equal length and have a common arc?