Setting the castor correctly

[Luigi Malone]

I am chasing my tail it seems. I am trying to get all the angles right and I still get the shakes and shimmies.
The FSM says to set the kingpin angle at nine degrees, and the castor at 3.5 degrees.
But at nine degrees of kingpin angle my handling seems to worsen.

What have you done to make your angles correct please ?

All input welcomed.

LM

[Luigi Malone]

BTTT
C'mon all you modifiers, and Zuk Gurus.
If I set the kingpin angle to nine degrees, how do I measure the castor?
Or will it be automatically correct?
Anyone ?
LM.

[OVERKILL ENG]

Okay as a general rule if you put an angle gauge on top of the kinpin plate try and make it flat first and set the angle at 0 then you should be pretty close.
SAM
ps I hope it makes sense.

[Luigi Malone]

Are you saying the kingpin plate should be set at horizontal?
The FSM states nine degrees, but doesn't show how what why or where.

Yes i'm confussted.
Can you shed a little more light please?
LM.

[OVERKILL ENG]

[quote="Luigi Malone"]Are you saying the kingpin plate should be set at horizontal?


Yes
SAM

[Luigi Malone]

Yes
SAM[/quote]


Well Sam, I have reset my axle without any shims and they are approx 3 to 4 degrees (kicked out at the bottom kingpin plate)
My shaking has moved down from 55 to 75 Kph to approx 45 to 55 Kph.

It is uncontrolable and only stopping will end it.

I will reset the axle to where the kingpins are verticle or as you say where the top of the top kingpin plate is horizontal and try again.

But could you please explain what the FSM means by 9 degrees kingpin angle ?

Cheers
LM

[OVERKILL ENG]

What suspension setup are you running??
I will try and get some Photo's of how to set it up and post them for you.
SAM

[Luigi Malone]

What suspension setup are you running??
I will try and get some Photo's of how to set it up and post them for you.
SAM

I have old man emu springs under the axle with revolver link type shackles front and back. The front old man emu springs are rear springs in a four pack configuration (as are the rear springs,) i.e. no overloads.

Ever since I did the rr up front and power steering it has been a complete b'stard to drive but I don't want to go back as I like the ride and travel / flex. It works well for a spua and is legal.
I have replaced the kingpin bearings and knuckle seals set toe in to 6mm and fitted a new steering damper.
The more I adjust everything the more I realise I am just chasing the wobble to a different speed zone where it hits a little bump and goes crazy.
It's good at a hundred Kph but as I brake to take a corner it will start to shake very bad, and as I accelerate again it will kick off untill I have to stop. ???
Any help definitely appreciated
LM

[Wendle]

I have replaced the kingpin bearings and knuckle seals set toe in to 6mm

I don't know much about suzukis, but most trunion axles are the same anyway.. TRY RUNNING ZERO TOE. More toe emphasises the castor angles effect of lifting the axle as the knuckle steers and exagerates the self centre effect of the castor, and is what is giving you your shake.
HTH

[skippy]

hmmm. I had a similar problem, nothing I adjusted fixed it, rather moved it to a different speed. so i set everything back to factory and put up with it.

now with the new tyres, properly balanced, the problem has disappeared.

how long has it been since you balanced the wheels?

I could be totally off, but it worked for me.

[Luigi Malone]

Thanks Wendle, trouble is I only adjusted the toe-in the other day in desperation from 0 toe-in to the 6mm. I have had the headshake for a lot longer than that.
Keep giving me ideas though, i'm getting more desperate than a fourteen year old.
LM

[Luigi Malone]

hmmm. I had a similar problem, nothing I adjusted fixed it, rather moved it to a different speed. so i set everything back to factory and put up with it.

now with the new tyres, properly balanced, the problem has disappeared.

how long has it been since you balanced the wheels?

I could be totally off, but it worked for me.

Yeah, it's been a while since I balanced the wheels, my bro-in-law suggested that too. I have some new wheels under the house so i'll fit them up and try it again.
But tell me, when you set everything back to standard, what did you set it to (degrees etc)
Cheers
LM

[greg]

how long has it been since you balanced the wheels?

This is a good point... I recall Love_Mud writing that he had a stack of mud that had gotten into his tyres and were causing all sorts of wobbles when travelling at different speeds...

I'll have a hunt for the thread.

[greg]

Here's the thread i was thinking of...

http://www.outerlimits4x4.com/PHP_Modul ... th+wobbles

But there is nothing in there from Love_Mud... Must be somewhere else...

[skippy]

Here's the thread i was thinking of...

http://www.outerlimits4x4.com/PHP_Modul ... th+wobbles

But there is nothing in there from Love_Mud... Must be somewhere else...

twas me with the problem in that post. it's fixed now with balanced rubber.

[Wendle]

Thanks Wendle, trouble is I only adjusted the toe-in the other day in desperation from 0 toe-in to the 6mm. I have had the headshake for a lot longer than that.
Keep giving me ideas though, i'm getting more desperate than a fourteen year old.
LM

Okey dokey.. Was worth a shot. Nissans are chronic for this, truck alignment places set the toe out 1 deg to get rid of it, and up the castor a little to make up for it.
I think a lot of the yanks that run long flexy springs in the front of these trucks run a panhard to stop the axle moving sideways and building up to the oscilation(sp) that you have...

[OVERKILL ENG]

Does it do it without the revolver shackles??
If so get rid of them or as Wendle said run a panhrd rod.
SAM

[Guy]

Greg you recall reading that in an email I belive, I have had the issue resolved with 3 sets of rubber, exactly the same issue death wobbles ..
Balance tyres .. no more death wobbles . .knock off one of the huge banana weights (200 grams a each) and "There Back""

Seems to only be and issue with bigger rubber I did all the other stuff as well bearings, seals, steering damper, steering adjustment, kingpin angle blah blah blah .. still had the issue as you said, just seemed to move what speed it happened at ..

[Luigi Malone]

Thanks guys, I was in the process of fitting my new mud tyres only to find one was flat. So I broke out the trusty but slow Hurricane compressor only to find it would barely pump. I then found that I had left the key on all night and the battery was as dead as a dead dingo.
So i'll have to wait overnight to sort this problem out. I am praying it is just tyre balance cos i'm at my wits end with thism, it's fast becoming a POS also. Funny you can't feel the tyres out of balance while driving isn't it ?
LM

[Luigi Malone]

I fitted two new tyres at the front and Le Voila, the dreaded wobbles have all but gone. I think i'll put the castor shims back in to make it the nine degrees in the FSM and go get all my street tyres balanced.
I would like to thank you all for your help.
This is wondrous, specially after months and months of all the bullsh!t I have put myself through.
Now I can concentrate on the hundred or so other zooky jobs I have lined up for myself, oh, and wheelin of course.
Thanks again
LM.