Author Topic: Bump Steer  (Read 8780 times)

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Offline sandycrack

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Re: Bump Steer
« Reply #60 on: February 22, 2014, 07:54:16 AM »
They went out of business with all the others a couple of years back and I don't know how to get in contact with them to get that info.  I'll do as Pat suggested and start working it out as I go.  Should start making progress with this starting Sunday.  I manage a computer room and seem to be there more than home.  Had I realized computer systems run 24 x 7 I might have done something different.
You smell that?

Offline WelderPat

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Re: Bump Steer
« Reply #61 on: February 22, 2014, 08:49:30 AM »
http://www.amazon.com/Chassis-Engineering-Building-Performance-Handling/dp/1557880557

 Sandy crack ,
Order this book , read it and then put it in your tool box . While I have done this stuff for a living at times it is a great reference .
 Instead of making the square tubes to simulate shocks like that one dumbass said take two pieces that will slide one inside the other and drill holes to simulate ride , full compression and full extension . This way you can check your suspension through cycles that are equal and unequal side to side .
 But I would look at the kingpin inclination angle very first .
If you work out the steering and then have to go back and rework the spindles to get the KPI correct you will have to start over on the steering .
There is always free cheese in a mouse trap.

Offline fabr

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Re: Bump Steer
« Reply #62 on: February 22, 2014, 09:29:03 AM »
Actually kpi should be called SAI(steering axis inclination). But as you said ,if the SAI is not right and therefore the  scrub radius is crap nothing else will matter . All I can do is assume that this exact copy is actually exact and was correct geometry design to begin with. It very well may not be the case as ds has said before since it seems that a lot of builders do not have a clue . Buyers don't either and are duped all the time.
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Offline WelderPat

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Re: Bump Steer
« Reply #63 on: February 22, 2014, 09:49:01 AM »
I'm old
There is always free cheese in a mouse trap.

Offline fabr

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Re: Bump Steer
« Reply #64 on: February 22, 2014, 09:51:23 AM »
So am I!!!! LOL!!!   KPI is for kingpin straight axles such as Ford pickups. A arms use the term SAI. I'm just a bit anal ,sometimes(when it suits my purposes LOL!!!!),about this stuff.
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Offline sandycrack

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Re: Bump Steer
« Reply #65 on: February 22, 2014, 12:38:33 PM »
Great suggestion on the mock up. As for the builder we will find out I too hope he had his shit together!  Now I have to get mine together!  Thanks again all for the help.
You smell that?

Offline dsrace

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Re: Bump Steer
« Reply #66 on: February 22, 2014, 05:13:27 PM »
So am I!!!! LOL!!!   KPI is for kingpin straight axles such as Ford pickups. A arms use the term SAI. I'm just a bit anal ,sometimes(when it suits my purposes LOL!!!!),about this stuff.

I pre-fer sai but usually say kpi because many have never heard not know the other but you are correct it is indeed sai! 


sandy for some reason I can view the pics it just say make sure i'm connected to the server.   with the help your getting on the this post you'll get it done just take the time and stay calm lol
remember no one is putting you down or calling anything a pos although some of us may come off this way at time and ya I know i'm one of them too. ;D
Don't never argue with an Idiot!
Because he will drag you down to his level and beat you with experience

Offline dsrace

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Re: Bump Steer
« Reply #67 on: February 22, 2014, 05:41:42 PM »
I tried logging out and logging back in twice and still can't view the pics
Don't never argue with an Idiot!
Because he will drag you down to his level and beat you with experience

Offline dsrace

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Re: Bump Steer
« Reply #68 on: February 22, 2014, 05:52:06 PM »
got it I had to log into photobucket for some reason.  you have one of those front ends. I cannot remember the correct name but I have always called them j arms but have been corrected on that a time or two but didn't listen lol   but that front end has a slight rake to the stroke of the arm. sooooo it is important that the distance in the bolt width of the rack spreader match the arms bolt on point of the bulk head and then you'll have to find the sweet spot up and down for the rack in relation to the steering arm points at the spindle. as well as the distance out from center of spindle to center of tie rod heim at the end of the steering arm so it match's at the bulk head to rack spacing. but you'll wind up high or low from equal to spindle because the of the rake the arms swing at. if you draw a straight line through the heim center on the arms they don't pivot 90* at the cradle from the bulk head but more like 22* ( guestimate from pic) so they actually swing forward and back in the motion along with up and down. that is the rake i'm talking about.
Don't never argue with an Idiot!
Because he will drag you down to his level and beat you with experience

Offline fabr

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Re: Bump Steer
« Reply #69 on: February 22, 2014, 10:55:31 PM »
Ditto.
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Online Carlriddle

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Re: Bump Steer
« Reply #70 on: February 23, 2014, 04:58:03 AM »
When I saw pic of rack, thought that was it mounted, so I was wrong thinking it was high. 

DS, I call them J arms too.  ???With this setup of arms wouldn't the rack spreader width change and get smaller the more forward you moved til it hit 0?  Only way to know is to get out there and do a little playing.
You can keep your CHANGE, I'd like to keep my DOLLAR.

Online Carlriddle

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Re: Bump Steer
« Reply #71 on: February 23, 2014, 05:45:32 AM »
Videos always good, but at 1:10-1:15 mark watch the black cars front tires when it pulls a slight wheely.


You can keep your CHANGE, I'd like to keep my DOLLAR.

Offline fabr

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Re: Bump Steer
« Reply #72 on: February 23, 2014, 09:50:08 AM »
I had a pretty hard time seeing it but if I saw it correctly  there was massive toe out /bumpsteer going on there during droop. As said before,many builders don't have a clue and neither do buyers. I guess when those 2 meet it's a moot point whether it's right/safe or not.
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Offline sandycrack

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Re: Bump Steer
« Reply #73 on: February 23, 2014, 11:26:58 AM »
The toe out is very obvious.  I fooled around with the front end early on in the build and it sure didn't seem to do that.  Time will tell all as they say.
You smell that?

Offline fabr

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Re: Bump Steer
« Reply #74 on: February 23, 2014, 05:03:17 PM »
Yep,we're wishing the best for ya!
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)