suspension

The “Coming Out” Party

It’s official! Robert has declared that his work on the JeepMonster will be done by August 13, and it will actually COME OUT OF HIS SHOP (on a trailer, but still…)!

Our plan is to show it off for a few hours (8 AM to noon) at the local 4Wheel Parts store (4001 E. Speedway Blvd., Tucson, AZ, USA) before bringing it to my house for the next phase of construction – you know, the part where I get to cut holes in his masterpiece for lights, steering, brakes/clutch, etc., etc., etc., and figure out where all the lines, wires, tubes, linkages, pipes, hoses, and so on will go.

If you’re in Tucson on August 13, and want to see the JeepMonster in person, this is the time to do it!

This will also be a chance for you to test your rig’s articulation, as Robert has said he’ll bring his RTI (Ramp Travel Index) ramp.

Categories: 6wd, 6x6, CJ-6, Custom Frame, Custom Jeep Body, Jeep, Jeep Frame, JeepMonster, suspension, tandem axle, Uncategorized | Tags: , | Leave a comment

Wizardry

I haven’t had a chance to visit Robert (R&W Custom Sliders & Offroad) this week, but he sent me some pictures of the progress he’s made on the front axle’s suspension. As far as I’m concerned, the man is a wizard. While it’s true that he has access to some awesome machines, he has to know how to use them to produce what he wants. I could probably learn to cut flat pieces, but his ability to work in three dimensions, and to know how all the flat pieces will go together to make a 3D assembly, are amazing.

First up, we have a photo of two coil-spring perches. While this is upside down (the curves you see at the top will fit around, and be welded to, the axle tube), you can see how a basic 3D shape can be made from flat pieces.

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Next we have the truss on the front axle. This is where the top two links (of four) will attach to the axle. You can see the curve on the right side where the new truss meets the axle tube, and on the left you can see that the top plate has a little tab on the near left corner to fit the differential housing accurately.

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This photo, from the back of the axle, shows how the plate had to be cut to fit around the differential housing.

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The next photo shows a lot of progress after the previous one. The spring perches, which also hold the lower links (and, eventually, the shock absorbers), have been added. The bracket to hold the upper links has been placed, but isn’t yet welded to the truss. The frame ends of the links are held in place so Robert can start designing and fabricating the brackets.

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Here’s a view of the axle end of the upper links. A lot of times the two upper links will be mounted to the axle independently, but sometimes (as is done here) they’re combined into one connection at the axle. I don’t know whether one way is inherently better than the other or not, but in this case it made life simpler at the axle end.

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The final view for tonight is a shot from the side. All this stuff, when it’s finished, will locate the front axle under the JeepMonster. Springs and shocks, of course, provide the cushy ride <wink wink>, and a GM 350 provides the go power.

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In other news, I learned that the right springs will be available from ADS on the 16th. I also finally found some acceptable U-bolts for the back axles; those have been ordered and are on their way. The clutch slave cylinder (that actually pushes the clutch lever when you push the pedal down) also arrived, so that can be bolted in to test for clearance issues.

I’m still looking for a new transmission mount. I’ve had my transmission / transfer case combination for 20 years, and the existing mount has reached its expiration date. However, that exact mount is apparently no longer made – I guess it was an early version of what they use today, but what they use today doesn’t fit. Nothing fits. There are three possibilities that might be usable; I’ll order them to see what Robert can do with them. The ones that aren’t used will be returned.

I’m also still looking for a new radiator. I think my old one was custom-made, but I don’t want to go that route again if I can help it, because even radiators in *standard* sizes are hideously expensive. But I have to make a decision soon, and order something, so that Robert can add that to the frame.

I also need to get the air tanks for the onboard air system. They aren’t a critical fitment issue, but if I get them now, Robert can add the mounting brackets to the frame before we start working on the body. It’ll be one more thing done at the (relatively) easy stage of construction.

Categories: 6wd, 6x6, CJ-6, JeepMonster, suspension | Tags: , , , , | 2 Comments

Round, Round, Get Around, I Get Around…

Before I get into this week’s tale, I want to correct the wheelbase numbers I posted last week. I should have caught the error at the time, but I didn’t. It turns out that the “inner” wheelbase is still about 98 inches (up from 81 on the CJ-5), but the “outer” wheelbase is actually around 138 inches, instead of the 130 I told you about last week. The reason I say I should have caught it is that I know the two back axles have to be about 40 inches apart, center to center, in order to clear 35-inch tires with a reasonable amount of space between them. So the outer wheelbase on the JeepMonster will be about the same as my truck’s. The shorter overall length (16 feet for the JeepMonster versus 18′ 8″ for the truck) is due to the lack of front and rear overhangs.

So, having cleared up that little tidbit, I’ll move along to this week’s visit with Robert – and the things that I had to get done before going.

It turned out that the stock JK Wrangler coil springs I had taken to him were about the right stiffness, but they were too long and too wide. So my assignment was to find something a couple of inches shorter (16 inches instead of 18), an inch less in diameter (four inches instead of five), and with flat ends instead of the square-cut coil ends that come from the factory. And oh yeah, I could also get some shock absorbers, too – Robert’s keeping his set for his own project. He gave me the brand name, the series number, and the SKU for the shocks he was using, and since I had all that, I decided to make life easy on myself and just get more of the same.

I looked online to find them, and discovered that 4 Wheel Parts had exactly what I wanted. I decided to go to the store to get them, on the theory that doing it that way meant that at least *some* of my money would stay here in town. Naturally, the store didn’t have any – they were on backorder and wouldn’t be in for a few days. Okay.

Next I asked the man behind the curtain – er, counter – if he had any recommendations or suggestions on how to find out how stiff the JK Wrangler springs were. Coil springs are rated in “pounds per inch,” which means that for a set weight (100 pounds, 200, 400, etc) the spring will compress one inch. I needed the JK’s spring rating so I’d know how stiff the new springs would have to be.

The 4 Wheel Parts counterman suggested I go see someone named Brian at someplace called ADS. Luckily, Mapquest (mobile) was able to find ADS Racing Shocks for me and off I went. I met Brian, and he was happy to show me what they had (they build coilovers, so they have lots of different springs on hand – all of which have flat ends and a four-inch outside diameter). Unfortunately, he couldn’t help me with determining the JK’s spring rate, but he knew a man named Paul at GAT Racing (Brian called it a “roundy-round” shop – GAT builds circle-track race cars) who might be able to help.

So, off I went to GAT, again with help from Mapquest. Paul was there when I arrived, and he knew exactly what I wanted (thank goodness!), so he took my spring back to the back and invited me to come along. He clamped the spring into a small hydraulic press and pumped the press until the entire spring was just slightly compressed. Then he zeroed out the force indicator and compressed the spring one more inch. When he was done, the indicator read 126, meaning that the spring was probably a 125-pound unit. This surprised me, because JK Wranglers can weigh over 1200 pounds per corner, but okay – that’s what the spring machine said.

Back at ADS, Brian went looking for comparable springs and came up empty-handed. In a 16-inch length, he had 100-lb springs and 400-lb springs, with nothing in between. Oh yes – he had *one* (used) 200-lb spring. So I bought a pair of the 100-lb springs and the 200-lb spring. I figured that Robert would be able to use one or more of them to at least begin fitting the spring mounts, even though the springs themselves were the wrong stiffness. I told Brian what I was doing, and he was okay with my plan to exchange the 100-lb springs for a pair with the proper stiffness, once we figured out what that might be (and as long as we don’t scratch the ones I bought).

I took the three springs, and a bunch of other pieces-parts, to Robert this past Wednesday. [The shocks arrived at 4 Wheel Parts on Wednesday morning, so I was able to take them to Robert, too.] As a test, we placed the 100-lb springs between the frame and the front axle and then let the frame compress the springs. They flattened out almost exactly four inches (from 16 down to 12-ish) before they fully supported the front end. From that we concluded that the front of the frame, with the engine and all, weighs about 800 lbs, equally supported by the two springs. That number will go up, of course, as we add the winch, and the body, and the fluids, and whatever else goes on the front.

We also checked out a couple of other things and then I came home. [I took some pictures of the transmission mount in the hope that either Advance Adapters or Novak Enterprises might be able to help me with a replacement.] On my way out, I took a couple of pictures of the forlorn remains of the CJ-5:

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So for my next visit, I’m supposed to have (if I can get them in time) the correct-strength coil springs, the new radiator, the right-length U-bolts for the back axles, and some information on the clutch slave cylinder I’ll be using (so Robert will know how to route other things around it).

Stay tuned.

Categories: 6x6, CJ-5, JeepMonster, suspension | Tags: , , , , | 2 Comments

Under. Over. Under!… Over?….

The JeepMonster’s exhaust manifolds arrived late last week, so I called Robert earlier this week to set up a time to take them out to him. We agreed that yesterday afternoon would be satisfactory, so I arrived at his shop about 3:30 to drop them off. While I was there, we discussed the springs – both the coils for the front axle and the leaves for the back axles.

Up until about a week ago, I had been working on the assumption that the back springs were going to be mounted above the axles, both to increase the clearance underneath them and to give additional space between the axles and the frame for flexibility and axle movement. When I talked to Robert about coming over, he told me he had decided that the spring-over configuration was going to be too high, and he had moved the springs under the axles – and that’s where they were yesterday. We both recognized that stock YJ Wrangler springs (which is what he had on hand and we’ve been using for the mock-ups) wouldn’t work in the spring-under-axle (SUA) configuration, because it left the axle and the frame too close together. So I’ve been (desultorily) looking for some springs with about 2.5 inches of lift. In the meantime, Robert was going to force the frame and axles apart by sticking a piece of steel between them, so that he could work on the front suspension.

Last night, I got a text saying, “Don’t look for springs yet – I want to do some more measuring.” O-kay…

Today Robert called me and said he had gone back to the spring-over-axle (SOA) configuration, and he sent me a couple of pictures.

This first one shows the middle-axle spring mounted on top of the axle and compressed (by the weight of the third axle) to about where he thinks it’ll ride when the whole JeepMonster is built and the full weight of the vehicle is on the springs. (The third axle, although not shown well here, is literally hanging about an inch off the ground. Robert thinks that’s a pretty good proxy for all the other weight, like a spare, a winch, a gas tank full of gas, a couple of batteries, and tools & parts, that’ll be weighing the back of the JeepMonster down when it’s all built.) In this photo the spring looks almost flat, but I think there’s still some positive arch in it.

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The next photo shows the front shackle. As you can see, there’s a definite forward cant to it, which is what you want when the spring is at what’s called “ride height” – in other words, when it’s just sitting in a garage, or when it’s going down the highway. Having this forward (or backward, if the shackle is at the back of the spring) slant allows the spring to flex better and gives a better ride than if it’s exactly vertical. And you *definitely* don’t want it angling back toward the spring, because then you have very little flexibility and you run the risk of reversing the shackle and jamming it up against the frame – which could cause bent or broken springs, a broken spring mount, or other severe damage to the suspension.

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The net result of going back to the SOA style isn’t really any different from getting some lift springs and mounting them SUA, but if I can use the stock springs we already have, then I don’t have to try to figure out whether to get 2 1/2-inch or 4-inch lift springs, and if I happen to break one, stock springs will be much easier to source than lifted ones.

But now I have to find longer coils for the front than I was originally looking for.

Here’s a photo Robert just sent me, It shows the middle axle flexed:

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He tells me the tires have 11 inches of travel between the fully compressed and fully extended spring positions. You can see the passenger-side spring is squershed flat, while the driver-side spring is fully extended. I think that’ll be fine – I’ve never intended this to be a super-flexy rig, anyway. What I can’t conquer with flex, I’ll try with locked axles; what I can’t conquer that way, I’ll either give up or use my winch.

Here’s another shot of the flexy Monster – it’s a *little* clearer to see the springs in this photo. You can see the back axle is still SUA, and if you look closely you can see the shackle on the far left corner is almost directly in line with the spring. It would be very easy at this point for the shackle to reverse itself and then jam up against the frame as weight comes back down on that corner. That would not be good.

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As a side note, he told me that the “inner wheelbase” is 98 inches and the “outer wheelbase” is 130 inches (or about 11 feet). The original CJ-5 wheelbase is 81 inches, and a CJ-6 wheelbase of the same vintage is 101. By comparison, my truck’s wheelbase (it’s a 2000 F-150 SuperCab) is 138.5 inches. The big difference will be in the overall length. The truck is 225.9 inches or about 18′ 8″. The JeepMonster will have much less overhang at both the front and the rear, although I don’t know yet what the final length will be. The frame is currently 16 feet, but the final length might be different by a little bit.

So if you’ll excuse me, I’m going to go look for information about coil springs, and maybe buy a pair.

Categories: 6x6, Jeep Frame, JeepMonster, Spring Over, Spring Under, suspension, tandem axle | Tags: , , | 2 Comments

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