'72 K5 - Greg's @MightAsWellK5 Build

[Greg72]

Welcome to Page 42.....




-G

 

[ryoken]

I missed it.. why do you need to mount it so far off the axle?



the TIG brings the SEXAY........

 

[Greg72]

I missed it.. why do you need to mount it so far off the axle?



the TIG brings the SEXAY........

Paul,

I don't think it will need to be as far away as it appears in those last photos. As Heath mentioned the bottom SHOULD be closer even if I leave the top mount exactly where it is now.

I'm having a tough time finding a landing spot for the upper mount that is any further forward than the spot I used last night.

I'll mess around with it some more tonight and try to tighten things up a bit.


-G

 

[4X4HIGH]

Greg, how about changing that inner horizontal bar so that it goes further back before tapering back in to the main horizontal bar or even the C-pillar if that's where it ends up and then mount the top of the strut off of some bracketry below the inner horizontal bar. I would also shorten and increase the angle of that rearward most diagonal bar from the C-pillar to the horizontal bedrail bar behind the wheel tub.

 

[Greg72]

Greg, how about changing that inner horizontal bar so that it goes further back before tapering back in to the main horizontal bar or even the C-pillar if that's where it ends up and then mount the top of the strut off of some bracketry below the inner horizontal bar. I would also shorten and increase the angle of that rearward most diagonal bar from the C-pillar to the horizontal bedrail bar behind the wheel tub.

Scotty,

I tried some flex tests again last night and even with the new temporary bracket locations...IT STILL RUBS!

Both the upper and lower mounts need to move inboard again to keep the tire sidewall off the strut body. I'm going to have to put the rear seat back into the truck to see how badly this is messing things up.... From the looks of it, thhe seat will need to go in front of these strut towers and the structural supports for the struts will end up directly behind the seat on either side. I know I've seen examples of "sleeper desert trucks" with full interiors where that's what you see when you drop the tailgate and look into the back area....

-G

 

[K20Chevrolet]

Scotty,

I tried some flex tests again last night and even with the new temporary bracket locations...IT STILL RUBS!

Both the upper and lower mounts need to move inboard again to keep the tire sidewall off the strut body. I'm going to have to put the rear seat back into the truck to see how badly this is messing things up.... From the looks of it, thhe seat will need to go in front of these strut towers and the structural supports for the struts will end up directly behind the seat on either side. I know I've seen examples of "sleeper desert trucks" with full interiors where that's what you see when you drop the tailgate and look into the back area....

-G

Greg,

wouldn´t it make sense, if you want to keep the seat in permanent (not sure if you do).... to put a seatbelt bar and two triangular bars behind the seat. that way you could tie the shock mounts in with each other and the frame with the triangluar bars AND you could run the 4/5 point harness for the rear seat too... just a thought, since you mentioned the "sleeper desert trucks".

Would there be enough room for your hauling duties behind the seat?

 

[Greg72]

I really don't want to divide the truck in half like that...

Hauling plywood was the ultimate test of a "real" 4x4 Truck project. It's hard to claim that you drive a real truck when you can't even do something as simple as that.

At the very least I want to be able to roll out a sleeping bag and have a decent amount of space back there to sleep. If I start dividing up the bed area with a bunch of diagonal tubing, I've pretty much lost the essence of what this project is supposed to be.... it needs to be a fun do-everything camping / exploring / rock climbing / highway-friendly 4x4.


Failing the plywood test is a huge disappointment, but that's where I draw the line on bed space compromises.


-G

 

[ashman]

I really don't want to divide the truck in half like that...

Hauling plywood was the ultimate test of a "real" 4x4 Truck project. It's hard to claim that you drive a real truck when you can't even do something as simple as that.

At the very least I want to be able to roll out a sleeping bag and have a decent amount of space back there to sleep. If I start dividing up the bed area with a bunch of diagonal tubing, I've pretty much lost the essence of what this project is supposed to be.... it needs to be a fun do-everything camping / exploring / rock climbing / highway-friendly 4x4.


Failing the plywood test is a huge disappointment, but that's where I draw the line on bed space compromises.


-G

Glad to hear you're sticking with it Greg. I agree that if you can't haul anything it's not really a truck anymore. You've solved trickier problems than this, the answer will come. I have faith.

 

[Greg72]

Glad to hear you're sticking with it Greg. I agree that if you can't haul anything it's not really a truck anymore. You've solved trickier problems than this, the answer will come. I have faith.

You know.......

Now that I think about it, maybe I could actually haul plywood on those dual-bedrail tubes instead of trying to lay them on the floor???

Loading the material would be a little more challenging (though I could certainly use the CTIS to let air out of the tires to drop the height by several inches) but then I could slide the sheets all the way in until they hit the diagonal down bars in the B-pillar area as a backstop!

That suddenly sounds like a really good idea and makes me feel less guilty about the next moves I'm being forced to make with the strut mounts.


-G

 

[Greg72]

2014.12.16 - UPDATE! - DOWN & BACK, DOWN & BACK..!!!!!


Yep.... wise man, that Brandon.

I tried another revision last night for the rear suspension, but still came up short of full-articulation. It IS getting closer though!

First off, I wanted to move the upper strut mount slightly forward so that I didn't have to build the lower mount so far off the axletube, and I didn't want to end up with a strut that was layed-back instead of vertical. So a carefully flapwheeled the edges of my existing 1-3/8" mounting plate hole so that I could swivel the DOM tubing at more of an angle (instead of mounting it at 90*)

That allowed me to push the mount forward about 2"....

Which then allowed me to weld up a quick lower mount pretty close to the axletube.... certainly close enough that I know I can plate it up and make it strong when the time comes. I also wanted to keep it as close to that backing plate as I could so that the struts would be wider at the axle end and narrower at the upper mount area.

The first tests were great. The axle went all the way up to full stuff on the passenger side, and the drivers side dropped all the way out. I even notched the frame so that that upper link mount bolt would clear!!!

Then I remounted the portal assembly (man, I'm getting tired of lifting that thing!) and put the wheel/tire back on and did the same flex test again.... but came up short:

I got full stuff on the PS, but there was still about 3" of droop left on the DS that I couldn't get.... the tire sidewall hit the strut body (again).

So... the experiment reveals that in fact both the upper and lower mounts are still a bit too wide. It will be a game of inches now to pull them in a bit more, and retest. As mentioned in earlier posts today, the side-effect is that the strut bodies themselves are coming inboard quite substantially now at this point, so they are going to start eating up valuable floor space.

What I also started to see last night is that the tire sidewall is coming in so aggressively at the last few inches of droop that the wheel tubs WILL have to be widened to accommodate them. There was a period of time when I wasn't 100% sure that was going to be necessary with my axle width and wheel offsets.

Anyway..... no more testing tonight. I'm off to the "CNC Playground" with a car full of 17" wheel hoops and welded centers. We're hoping to get the remaining 4 wheels (17" White Wheels & Hubcaps project) completed tonight!!!



-G

 

[folkenheath]

Nice tests Greg, sounds like you should offset the wheels on the wide side of the tolerance. You'll get there and you'll be happy with the results when you do.

 

[Greg72]

Nice tests Greg, sounds like you should offset the wheels on the wide side of the tolerance. You'll get there and you'll be happy with the results when you do.

Thanks!

I actually had to trim my rockslider by about 3/4" last night.....my ROCKSLIDER!!!

The tire tread was hitting it when I started to get massive bump/droop combinations!! Weird stuff happens when the axle has THAT much travel....


-G

 

[folkenheath]

With your portals the tire may move forward or back slightly as the pinion angle changes with suspension travel? That would be my guess.

 

[A1971Blazer]

Thanks!

I actually had to trim my rockslider by about 3/4" last night.....my ROCKSLIDER!!!

The tire tread was hitting it when I started to get massive bump/droop combinations!! Weird stuff happens when the axle has THAT much travel....


-G

You're likely getting some flex-steer at the rear axle. This is inevitable when two links are triangulated and two are straight. When on side droops and the other compresses the axle will "steer" slightly one way and the other.

 

[folkenheath]

Your speaking to one of the writers of the 4 link calculator, he probably knows exactly what his roll steer is.

 

[jekquistk5]

Your speaking to one of the writers of the 4 link calculator, he probably knows exactly what his roll steer is.

lol

 

[miniwally]

2014.12.16 - UPDATE! - DOWN & BACK, DOWN & BACK..!!!!!


Yep.... wise man, that Brandon.

I tried another revision last night for the rear suspension, but still came up short of full-articulation. It IS getting closer though!

First off, I wanted to move the upper strut mount slightly forward so that I didn't have to build the lower mount so far off the axletube, and I didn't want to end up with a strut that was layed-back instead of vertical. So a carefully flapwheeled the edges of my existing 1-3/8" mounting plate hole so that I could swivel the DOM tubing at more of an angle (instead of mounting it at 90*)

That allowed me to push the mount forward about 2"....




Which then allowed me to weld up a quick lower mount pretty close to the axletube.... certainly close enough that I know I can plate it up and make it strong when the time comes. I also wanted to keep it as close to that backing plate as I could so that the struts would be wider at the axle end and narrower at the upper mount area.

The first tests were great. The axle went all the way up to full stuff on the passenger side, and the drivers side dropped all the way out. I even notched the frame so that that upper link mount bolt would clear!!!

Then I remounted the portal assembly (man, I'm getting tired of lifting that thing!) and put the wheel/tire back on and did the same flex test again.... but came up short:

I got full stuff on the PS, but there was still about 3" of droop left on the DS that I couldn't get.... the tire sidewall hit the strut body (again).

So... the experiment reveals that in fact both the upper and lower mounts are still a bit too wide. It will be a game of inches now to pull them in a bit more, and retest. As mentioned in earlier posts today, the side-effect is that the strut bodies themselves are coming inboard quite substantially now at this point, so they are going to start eating up valuable floor space.

What I also started to see last night is that the tire sidewall is coming in so aggressively at the last few inches of droop that the wheel tubs WILL have to be widened to accommodate them. There was a period of time when I wasn't 100% sure that was going to be necessary with my axle width and wheel offsets.

Anyway..... no more testing tonight. I'm off to the "CNC Playground" with a car full of 17" wheel hoops and welded centers. We're hoping to get the remaining 4 wheels (17" White Wheels & Hubcaps project) completed tonight!!!



-G

This was my original Buggy axle, I believe the front and back tabs to be 3/16" material, one bent for the back and the other I think stands straight up off the axle tube. Of course the side plates for the links are 1/4" material and are the beef of the mount. This is what the early versions of the ORD rear 4 link kit did to solve your issue. YOu can snoop around and probably find some pictures of my buggy from the back before we cut it up and made it all desert racer cool. It worked well for a good rec. crawler and was really only changed to get 20" of rear wheel travel.

Keep the bottoms as wide as possible and lay the top in, a few degrees of angle isn't going to hurt in full bump situations and will help make the strut progressive in full articulation situations.

Here is a link to the Fox chassis when ORD did it years ago. Basically his rear axle was a copy of mine, you can see shock mounting locations for side to side reference. http://coloradok5.com/uav.shtml

 

[Greg72]

Your speaking to one of the writers of the 4 link calculator, he probably knows exactly what his roll steer is.

OK....that's true. That piece of "freeware" made me a bit of a celebrity on the internetz.


But to be fair, even my spreadsheet failed to calculate the "one wheel up, one wheel down" type suspension movements. The wheel travel and associated roll-steer calculations were all based on simple wheel travel (both wheels up or down simultaneously). It's better than nothing, but it also doesn't tell the whole story for a 4x4 rockcrawling application..... this corner-case, max bump/droop stuff just isn't part of that software.

I remember asking Dan Barcroft (Triaged) about the math involved to calculate those types of articulated motions, and he said it would require solving lots of simultaneous equations and a LOT of work that I was simply not prepared to invest.

Realistically, the calculator will the most important parts of suspension design and allow for rapid design and modeling of ideas, and most importantly... the quick revisions of bad designs into better ones!


-G

 

[sreidmx]

Why not run a small spacer instead of moving the mounts again? Looks like your off maybee an inch or so?

 

[rdn2blazer]

2014.12.08 - UPDATE! - 12 NEW SPEED HOLES..!!!!!


Let me tell ya something...... making cool-looking holes in metal takes a LOOOOONG time.


Thats because you NEED an iron worker like I do too . You are correct, milling manually or drill press and a hole saw sucks big time. All those holes would take seconds in a punch on an iron worker. You would have more time changing the punch dies then popping the holes in the plate. You'd get warpage on a plate like that but no big, straighten it and you're good to go. Or alternate side to side so it straightens it back as you alternate sides. An Edward's 55 or 60 ton Iron worker is on my bucket list my friend. I feel your pain lol. Been there too many times myself. See, now you KNOW you need one too.