Physics of shock mounting & SOA?

[4X50 Exploder]

I will soon be embarking on the SOA conversion for the chassis from my ’92 Exploder. So far, the plan is to weld new perches on, angling the carrier directly toward the X-fer case while using a Double Cardan joint. It looks like I will need to remove/relocate the sway bar mounts for re-use. I have cruised through the SOA posts and have some questions about the best route for shock mounting.

1. Is the factory angle of the shocks (center to side) actually the ideal angle to end up with?
   
2. When it comes to the new location of the lower mounting point; is there an advantage or issues with attaching at the midpoint of the axle tube vs. higher up?
   
3. Would mounting the shock in the center of the axle tube give me a better range of shock travel than a stock length shock mounted on the top of the springs?

It seems like most conversions have gone with flipping over the stock mounts for the shocks, reversing them and re-installing them above the springs. For some reason this is just giving me an uneasy feeling so I am posting to see if there is a better way… I will have it all torn apart soon and hope to have some feedback prior to my starting the fabrication work…

I would love to hear anyone's thoughts or from someone that has done the conversion and their ideas and lessons learned…

 

[unclemeat]

The stock and remounted shock locations are not optimal. The best location for the shock is outboard of the spring. I do not think it is practical, but the closser to the end of the axle the better. Straight up and down vertical is the best shock angle. Once again not practical on a simple SOA. The other shock mount conundrum is mounting the shocks on the same side of the axle tube. My 04 Level II Ranger (stock SOA) mounts the shocks on either side of the axle tube. This gives better shock performance and reduces axle wrap.

The simple SOA conversion process allows you to run stock length rear shocks. If you really want to do a better shock mount, you could weld tabs on the axle tube and use a custom (longer than stock) shock. This will require a bunch of extra work, nless you can find someone who has done it. You would need to cycle the suspension and measure the compressed and colapsed shock lengths. Then order the appropriate lenght shocks. You could also modify the upper shock mounts, but that would take some custom fabrication and may require modifing the rear cargo area. So you can see why almost everybody just relocates the spring perches on top of the axle tube.

 

[4X50 Exploder]

Well, like any good reply, you have added other questions to my list.

It would not hurt my feelings to modify or totally loose the existing cross member that the upper shocks mount to. I will be putting a pickup bed on here and the humps for the existing shock mounts are going to be an issue anyway. I already plan to cut out and/or modify the cross members that held the spare tire and turn that area into locking storage that’s accessible from the bed of the truck.

The way that my mind is grabbing this right now; it seems like if I lose those humps, to get the top of the shock down even with the top of the frame and move the shocks further outward, the shock would be WAY too short! Keeping a hump but putting the top of the shocks close to the frame might give me enough room to clear the sway bar, attach further out above the springs, and position the passenger side shock in front and diver side aft of the axle.

1. What have people done if they want to retain the use of their anti sway bar?
2. If the shocks were straight up and down, wouldn’t it allow the rig to sway side to side easier?
3. Will a shock that has an external reservoir or larger diameter allow you to have a shorter profile without loss of travel?

 

[unclemeat]

Check this out, the rear dual shock set up. It is for a Ranger, but is a very intersting set up.

http://www.jamesduff.com/broncoII/dualshock.html

1 Most have removed the rear swaybar. I still have mine on my X. But once I get the steering straight I will at least be adding a quick disconnect. Using a high performance shock will gererally compensate for the removal of the swaybar.

2 The purpose of a shock absorber is to dampen the spring ossilation. A spring when compressed will rebound and recompress and rebound, like when you drop a basket ball. The shock will therotically allow the spring to compress and rebound in a controlled manner. When I said vertical I mean perpendicular to the axle movement, which may not acctually be plumb vertical. You will have to cycle the supension to see the axle path.

3. Shock travel is a function of the axle movement. Locating the shock inboard will shorten the travel distance, provide less shock performance. A monotube shock (Bilstein 5100) is a good tradeoff. Remote reservoir shocks and and monotube, provide better colling of the oil in the shock. Shock fade is when the oil boils and the shock stops doing its job. Then the spring looses its dampening function and acts like a ball. Then you loose traction.

 

[4X50 Exploder]

Are you saying that you are still using your rear sway bar with the SOA? If so could you shoot me some pics of how you have yours is set up? that is one of the things I want to do with this conversion.

I spent better than a month trying to corrispond with J.D. I was going to go with their complete package, duals front and rear. Eventually they emailed back that the dual front and all rear components were discontinued for the Explorer but they may be bringing them back in the future. By then I was so frustrated with them, I went with SuperLift...

Looking at their dual rear package, the shocks sticking below the axle tube is one of the biggest things I want to avoid!