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  #21  
Old 09-14-2012, 11:46 AM
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GeoTracker90 GeoTracker90 is offline
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Quote:
Originally Posted by Jdodd View Post
I may have a little ocd but I hate building stuff that I have to make precise measurements on because off the room for human error so when I design stuff I make it all self jigging and every thing will only fit one way. Unlike most i've seen where they just run tubes and not have the uppers and lowers connected it leaves room for error or a whole lot of measuring So thats why its all designed to be build on its own then frame built off it. And the easiest way to get the caster set is by just bending the fame right before whole assembly.
If the easiest way of getting the caster set is as you say then why don't we see anyone else doing this? One of the last suspensions that I remember hearing about that included bending a component to adjust angles would be the old I-Beam suspensions. Bending is not easy. On those you need to be able to chain the beam down to the ground and then bend it with a bottle jack, or run a chain around the beam and over the top of the bottle jack.

Instead of this approach almost all modern susensions use adjustable joints. If you go back and look at the photos of the competition rigs earlier in this thread you will notice that the lower A-arms appear to be of a fixed length while the upper arms have adjustable joints where the A-arm attaches to the frame of the vehicle. Turning a bolt/rod end joint in or out and then securing it with a jam nut is a whole lot easier than bending what should be a structural component of your vehicle. If bending to make suspension geometry changes was easier or more accurate then I would expect to see it on the high dollar desert racers. These guys spend unreal amounts of money to build jigs to assemble multiple parts for their trucks and they build adjustment into their systems.

To each his own and I wish you the best. Please continue to share your progress with us. I think that what you are doing is an awesome project and I'm very interested in seeing how it turns out for you. Who knows I just may have to give this a try myself one day. In the mean time take a look at the following link. This is a local build where the guy is using jigs to build the components for a long travel A-arm Baja Bug.

VW Baja (Not 4X4)

Mike
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  #22  
Old 09-14-2012, 12:08 PM
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I think you have caster and camber confused.
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  #23  
Old 09-14-2012, 01:22 PM
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Hijack

Quote:
Originally Posted by GeoTracker90 View Post
This is a local build where the guy is using jigs to build the components for a long travel A-arm Baja Bug.

VW Baja (Not 4X4)

Mike
That is a nice build at least from the quick look I just took.
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  #24  
Old 09-14-2012, 01:51 PM
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Quote:
Originally Posted by Jdodd View Post
I think you have caster and camber confused.
Caster - a line drawn between the upper and lower pivot points as viewed from the side. If the top of this line is forward of the bottom pivot point location then the caster is negative. If the top of this line is behind the bottom pivot point then the caster is positive.

Camber - a line drawn between the upper and lower pivot points as viewed from the driver seat. If the top of this line is closer to the centerline of the vehicle than the bottom pivot point then the camber is negative. If the top of this line in further from the centerline of the vehicle than the bottom pivot point then the camber is positive.

An easy way to remember this is to look at your hands. Hold them out flat in front of you with the palms down, fingers and thumbs extended. Your fingers point forward and your thumbs point to the center. Your fingers are representative of the top joint in a negative caster situation; your thumbs are representative of the top joint in a negative camber situation.

For a much better explanation of suspension angles take a look at the following link: Tire Rack Alignment Angles Article

With the suspension systems shown on the desert race cars earlier in this thread the lower A-arm has all three pivot points fixed, while the upper arm has one fixed pivot where it attaches to the spindle and two adjustable pivots where the A-arm attaches to the frame.

If you adjust both of the upper frame attachment pivots out an equal amount the camber will become more positive and the caster will remain unchanged. If you adjust the front pivot out and move the back pivot in an equal amount, or leave it alone, the caster will become more positive, but the camber will change also. This is why when performing an alignment you typically adjust caster first, camber second, and the toe setting last.

I believe that my understanding of caster and camber is correct but please explain to me where I am confused.

Mike
(recovering mechanic and alignment technician)

Last edited by GeoTracker90; 09-14-2012 at 02:24 PM. Reason: Can't spell
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  #25  
Old 09-14-2012, 03:27 PM
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I see what you are talking about now but I would not try to get all of your caster from just adjusting the frame side heims just some fine tuning.

If you look at just about all the ifs buggys the frame side heim's are treaded all the way in. So they are designing their caster into the frame or the control arms.
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  #26  
Old 09-14-2012, 05:00 PM
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True - Start with a good design and build in some adjustment so you can take care of the real world that we live in. As you weld the chassis and suspension components there will be some minor (or major) pull on different structures depending on where the welds are, the material thickness and how it is allowed to cool, along with a dozen other variables.

Mike
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  #27  
Old 09-17-2012, 03:08 PM
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Another long travel A-Arm build:
'64 BUG A-Arm Build

Enjoy!

Mike
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  #28  
Old 10-25-2012, 06:03 PM
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Twisted Minis Twisted Minis is offline
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This is an interesting thread for me, as I have been thinking about this for an IFS 4Runner, daily driver/camping vehicle.
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  #29  
Old 06-08-2013, 02:54 AM
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matthedingoduk matthedingoduk is offline
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Hasn't been anything posted in this thread for a while, hoping there's still people out there that are interested in this subject. I just recently started looking into this and am too having trouble finding info on this exact build. I am going to start designing my extended a arms, I'm going to be using the T100 axles but I'm not quite sure what to do about shocks. I'm not too educated on them and don't know if I should switch to coilovers? From what I've read it sounds like if I switch I can ditch the torsion bars? I'm not looking to do anything extreme with my truck so I'm trying to figure out how far I should take the suspension. Any and all help is greatly appreciated! Hope to see this thread go further in the direction of extending the Yota a arms!
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  #30  
Old 11-04-2013, 02:01 PM
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R.DesJardin R.DesJardin is offline
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Bringing it back up.
So let's say I'm building a IFS setup for my solid axle Toyota, using a Supra center and building all my own suspension system for the stock solid axle Toyota frame.
Now the truck is seldom if ever highway driven, never faster than 60mph for maybe 10 min max. So I could drive slower if needed. Usually trailered by the way. Design is for wheeling mountains and deep snow, but some midwest hilly stuff too.
The question is how important is chamber gain in what will normally be what I consider slow speed applications of 0-40mph?
How critical is having a fully adustable suspension for this application?
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  #31  
Old 11-04-2013, 02:18 PM
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Quote:
Originally Posted by R.DesJardin View Post
Bringing it back up.
So let's say I'm building a IFS setup for my solid axle Toyota, using a Supra center and building all my own suspension system for the stock solid axle Toyota frame.
Now the truck is seldom if ever highway driven, never faster than 60mph for maybe 10 min max. So I could drive slower if needed. Usually trailered by the way. Design is for wheeling mountains and deep snow, but some midwest hilly stuff too.
The question is how important is chamber gain in what will normally be what I consider slow speed applications of 0-40mph?
How critical is having a fully adustable suspension for this application?
A minor thing to consider; somewhere between 30 and 40 Miles Per Hour you reach a point where you have enough energy to more then likely suffer fatal injury, where at speeds under 30MPH you are likely to survive. Slow speed is under 25 in my book.
As to camber gain it seems to be that if you are making the effort to design from scratch then you should spend a little more time to get it... And yes I get it, more time, more compromises, etc.
Addressing adjustable, my opinion is yes it should be adjustable in some range allowing you to bend it a little and adjust it back rather then bend a little and cut it off and start over...

E
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  #32  
Old 11-04-2013, 02:23 PM
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I can't say how much Camber Gain will matter. I know the TTB guys deal with ALOT of Camber change, so it sounds like its not too huge of a deal as long as its tolerable at ride height. Still, it doesn't sound like its too incredibly complicated to minimize it using a shorter upper arm.

Having done alignments and such, I personally would want at least some adjustablity built in to the system, but that is easy by just using a heim instead of a uniball. Even for slow speed stuff, you are going to want adjustable caster, as it makes a huge difference on the self centering aspect of the steering even at slow speeds and if its off you get at best a steering that needs constant correction and could have a lot of death wobble. When I've gotten death wobble on my solid axle rig in the past, its always started in the 15-30mph range and I would have to slow down all the way to 10mph to make it go away.

That is for a custom built option though. You'll notice that the Total Chaos kit doesn't have ANY adjustability in it, but they have also gone through extensive process to design that system so they know what geometry works well and are comfortable locking it down.

Just my thoughts on it. Having seen your work on other stuff, I'm sure you could make it work and make any changes needed in fab world (cutting and remaking it) if you didn't want it to be adjustable on the fly.
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  #33  
Old 11-04-2013, 03:26 PM
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R.DesJardin R.DesJardin is offline
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I ask about the camber gain because after reading Mr. Adams comments it seems less than important for most applications. Well that's what I got out of it any way.
I ask to get general feedback because I didn't want to design in something that wasn't needed.
For sure caster is a huge issue and having it adjustable has been my plan, heims for upper control arm mounts I'm thinking.
This will be fun.
Haku thanks for the compliment. Last night I machined the Supra diff front mounting points to be all planar. This will take some time and I plan to have this all mocked up in the shop.
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  #34  
Old 11-04-2013, 03:45 PM
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Sweet....wanna make 2 of these while you are at it :P I kind of kid, but if you were willing that seems like something I've been thinking about too and would be interested as long as the dollar amount was right. With the move towards IFS in the offroad world (as has been discussed heavily already in this thread) I think there might be room for making this a kit one could purchase.

Like I said, the TTB/Beam guys have massive amounts of camber change...



... and it seems to work fine and the guys using them have race wins all the time. Entropy does make a good point though, if you can do just a bit more design work and get it so that camber stays relatively the same through the suspension travel, then it seems worth doing too.

As far as I can tell, keeping the camber consistent is similar to keeping the pinion angle the same on link suspension system in that the two arms are different lengths. I'm sure its a bit more complex, but the same idea.
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  #35  
Old 11-04-2013, 04:33 PM
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Funny you ask about a kit since most people think you needs gobs of flex that can be proven with a fork lift and must be coil overs and links. I don't, and I'm not building a pre-runner. Just trying to get the truck to take the small rough stuff better and a liitle better ground clearance in the front.
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  #36  
Old 11-05-2013, 12:48 AM
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Camber gain is important. It helps reduce body roll during a turn and keeps you from rolling the tire off the rim.
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