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Nice Comanche race truck build

Goatman said:
I'd like it better if it was a uniball. I have no idea what experience racers have had using a rod end in that configuration. I can say that a 1.25" chromo rod end has a monster load capacity, but that load seems to be against the shaft/threads of the joint. I don't know what the load is.

We can't see a pic, what does it use on the bottom?
Click to expand...
Look down farther, the pictures there show a spherical bearing being used, but it's attached to a shank still? Yeah ideally you should not run a rod end or threaded shank in shear but with the square bolt clamp it should keep the shank from bending. We use Jam nuts and as long as they are tight the shanks don't bend. Load capability of rod ends is usually in reference to the ball and race not the shank iirc. The shank would be easy to figure though it's just a bending moment. ~30.8kips

However a spherical bearing that is built into the arm or spindle in this case would be stronger as you have more cross area to transfer the stresses.

While it's a neat idea, I'm not sure I see the need to an adjustable spindle in that direction as it looks like it would adjust your camber and castor. Usually you only need to adjust camber and even then once you get it dialed in, it doesn't get changed so why make it adjustable?
 
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Goatman said:
I'd like it better if it was a uniball. I have no idea what experience racers have had using a rod end in that configuration. I can say that a 1.25" chromo rod end has a monster load capacity, but that load seems to be against the shaft/threads of the joint. I don't know what the load is.

We can't see a pic, what does it use on the bottom?
Click to expand...

It is pretty hard to say what they are using for the lower mount. It seems to be a heim joint but I really can't tell for sure.

My best guess would be to have some adjustable camber. I would think in a desert race one degree or so of negative camber would help cornering. Depending on the track/race this would allow adjustment as needed It could also be replaced quickly during a race if needed.

I would think upper and lower uniballs would be stronger, but they would also take longer to replace on a pitstop. If the uniballs were mounted on the outer knuckle that would make probably the time to replace them about the same, if the knuckle was complete with hubs and rotors..

I did notice on A-arm type suspensions the uniballs are mounted on opposite planes. The lower is vertical and the uppers are horizontal planes.
 
I am definitely not a engineer, but as many heims that I have seen sheared off right at the top of the rod portion of the heim, I would still like to hear his reasoning, It might be right on. The heim clamps are definitely way better that just the jam nut, and it increases the strength of the heims shaft since the entire thread area is clamped, just not cheap!
 
The reason has to be for camber adjustment, and since we can't see it clearly I'd assume the lower is a uniball. His experience might tell him that the combination is strong enough.....who knows? Poly Performance and others sell the clamp type rod end inserts.

I wouldn't think any of it would be so they could change that rod end quicker in a race, the need to change it would already mean the knuckle has come off. I can't see it wearing enough to need an in race change, and you wouldn't know it anyway, it would have to break......which you definitely wouldn't want.
 
FordGuy said:
Whats the opinion on how well the stock frame is going to hold up around the link arm cross member?
Click to expand...

I looked again really close and it is welded to the stock metal. It's double/tripled up in that area, and there is quite a bit of surface area covered, it should be plenty strong. I've done it both ways, welded right to the stock frame, and plated it before welding to it. I prefer plating, as I had one failure due to the layers of the stock metal pulling apart, even if you use a very thin plate. But, if you plate it, you need to have plenty of plug welds so the stress point on the plate isn't just around the edges at the welds.....that's not making it any stronger. I also like plating it so you can get a better weld against the good steel in the plate rather than that funky thin galvanized crap. However, I also have had no problems with well designed mounts welded directly to the stock metal.

In this case, I think it's plenty strong enough, and some of the twisting force against the crossmember is well braced by the tube that reinforces the upper arm mounts. Plenty of surface area covered, and plenty of weld length.
 
When I first glanced at the original pic's, it looked like it was welded on the stock frame, I thought that's odd since he has done such a beautiful job framing up the rear. Looked again at some of the new pic's, and can see what you are talking about.
 
Isn't that a Hesco aluminum head on it? If it's a really well built 4.6 or 4.7L stroker, it might not be too bad. Most of our rigs are pretty heavy, I've never weighed mine, but with all the plating and cage and rock rails and bumpers and skid plates and axles it's got to be heavy. Mine does decently with the 4.6L stroker, and I know it's not as well built as that one should be. It would be interesting to compare weights.

Clive Skilton competed very successfully with a well built XJ truck with a 5.0L stroker a number of years ago, that thing was bad ass in it's day, and still bad ass now. I wonder where it is?
 
Goatman said:
Isn't that a Hesco aluminum head on it? If it's a really well built 4.6 or 4.7L stroker, it might not be too bad. Most of our rigs are pretty heavy, I've never weighed mine, but with all the plating and cage and rock rails and bumpers and skid plates and axles it's got to be heavy. Mine does decently with the 4.6L stroker, and I know it's not as well built as that one should be. It would be interesting to compare weights.

Clive Skilton competed very successfully with a well built XJ truck with a 5.0L stroker a number of years ago, that thing was bad ass in it's day, and still bad ass now. I wonder where it is?
Click to expand...

I've seen pictures of skilton's XJ, but I can no longer find them anywhere. You are talking about the black 2dr that was linked front and rear with fiberglass all around right?
 
Yeah, and it had some monster 1/4 eliptical springs in the rear. Like 15-20 leaves in them.
 
Goatman said:
Yeah, and it had some monster 1/4 eliptical springs in the rear. Like 15-20 leaves in them.
Click to expand...

I wish I could find those pictures, I originally saw them about 4 years ago, and haven't been able to find them since.

Justin
 
Goatman said:
Yeah, and it had some monster 1/4 elliptical springs in the rear. Like 15-20 leaves in them.
Click to expand...

I have not heard someone bring up that design in 10 years. I had a Friend that bought a old either class 8 or 1 truck (can't remember) but he never could end making it work, kept braking the rear leaf pack where it had this huge pre-load Allen bolt.
 
5-47024-BlueLeduc.jpg


this is the one.....
 
There's one more of it here, but it has been repainted, and it ran in the Jeepspeed Mopar outlaw class.

http://www.aempower.com/ViewNews.aspx?NewsID=119

I Also found some Pictures of Curt Leduc's Sky Jacker Grand Cherokee.

The one thing I don't understand from the picture I just posted was the number.
It's running in Class 8. I figured it would be in Class 7 because Class 8 was full sized trucks...

Justin
 
Here's the one of LeDuc's ZJ, but I can't seem to find any other picture od either. Both of those Seem to have ran the Baja in 2003 and possibly some MDR BITD events but I'm having trouble finding it.

untitled.jpg


Justin
 
FordGuy said:
xcm said:
is there any reason to have huge frame rails all that way back when the 4 link rear mounts are around the b-pillar, with the shocks right behind that... Would it be preferable to go full tube from pretty much the b-pillar back, with the frame rails curving in and back, similar to these pics, ending at the shocks mounts?

The weight from two project tires, a jack, spare axle, drive-shaft, and add a 40 plus gal fuel cell hanging off of the back is a ridiculous amount of weight, not to mention what happens when you get bumped by an ass like Robby Gordon.



I]
Click to expand...
thanks for the answer.
anyone else have any opinions on this? im sure it CAN be done, with enough tube and triangulation.... hell the TT's do it! and i dont plan to go withint 20mph of their top speeds or duty cycle. maybe with mounting the cell as close to the cab as possible, and only running 1 spare? this wouldnt see baja racing, at most MDR or something stateside. and how would you mount a tube chassis to a somewhat stock, but reinforced front end?if you attached it at like 15-20 points, would the jungle gym effect be enough to keep from ripping it off?
Click to expand...
 
Goatman said:
So, do you have any tech to discuss??

:D
Click to expand...
NOPE, NONE TO BE FOUND. im neither testing anything, nor building anything at the moment, this could be considered my 'research stage'
thanks for breaking balls and pointing out my inferiority though!
 
xcm said:
NOPE, NONE TO BE FOUND. im neither testing anything, nor building anything at the moment, this could be considered my 'research stage'
thanks for breaking balls and pointing out my inferiority though!
Click to expand...

Hey, don't worry about it, I was teasing you. (you know, smiley face and all) I got a kick out of you saying let's get it back to tech and then posting links to other articles. Good articles, BTW, but nothing in them specifically about building a desert truck or vehicle design. Like you, I'm reading and researching stuff all the time, it's part of the enjoyment of the sport along with building them and using them.



xcm said:
anyone else have any opinions on this? im sure it CAN be done, with enough tube and triangulation.... hell the TT's do it! and i dont plan to go withint 20mph of their top speeds or duty cycle. maybe with mounting the cell as close to the cab as possible, and only running 1 spare? this wouldnt see baja racing, at most MDR or something stateside. and how would you mount a tube chassis to a somewhat stock, but reinforced front end?if you attached it at like 15-20 points, would the jungle gym effect be enough to keep from ripping it off?
Click to expand...

Yes, you can build it with more tube and less frame. Where you cut the frame doesn't matter as far as strength goes, the attachment of tube to frame is the same regardless of where you do it. Check out Capt Ron's MJ buggy or my XJ buggy for examples of what you're talking about, and there are plenty of others. However, there's no particular benefit to having more tube and less frame other than getting the design parameters that you're after. Many buggies and desert trucks are fabbed up with rectangular tube or stock frames to meet class requirements, no real difference between using all tube.
 
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