Under axle trusses

Stan

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This is just an informative question on my part and would like to hear the experienced and knowledgable answers on this.

How smart is it to truss the axle along the bottom, particular a front axle? And does anyone know of someone who's had trouble with running the truss into rocks and such and bending and breaking stuff from having the under axle truss?

Thanks.

I'm not here, nor was I here, nor will I ever be here.
 

BlueCoyote

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Depends upon how they are installed. While doing the rock krawl thing I have seen many of the bolt on truss's get hung up, broken, torn off. They were completely ineffective. Personally I would not use them. The straight axle Toyota's 79-85 had a factory installed lower truss welded to the housing. The biggest and best was the 84-85's - they would be a good design to look at. . The extra inch or so that they hang down below the tube is not really ever an issue on the rocks. If I recall you have a K5 - guessing a D44 or so. My suggestion is a welded on truss, utilizing a flat bar under the diff (a 1/4 or 5/16 should not make much of a differenc) and either cut round or square tube under the axle tubes. Do not use a rod design, but instead one that is fully enclosed material.You want to keep the truss as close to the axle and all the edges as smooth as possible. Smooth will not get hung up as bad on rocks.

Who are you calling Coyote ugly?
84 Toyota p/u Rokrawlr
86 4rnr
80 Toyota MDR Project
 

Stan

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Here's the reasoning behind my questions. Yes, I do have a K5, but I'm not a rockcrawler. I hang on a rockcrawling board, name left out for obvious reasons. The truss question came up, and pics were posted by not only a crawler, but a racer, and someone with "some status" on the board is flaming these people. So I jumped in, cause a lot of the pics I've seen of straight axle racers have under axle trusses, so I called him on it, and he flamed me back and said the under axle truss is a liability and that a lot of racers have knocked them off and such. I'm just gaining some knowledge on my part.

I'm not here, nor was I here, nor will I ever be here.
 

JCA

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I have seen the post on the other board and I have been trying to think of under axel truss's that are on race trucks and can not think of many. My self it is either front, back or top, bottom is not an option. Only thing that goes on the bottom is a skid plate. Again just my opion

J.C. Andrews
Andrews Racing
www.andrewsracing.com
 

ntsqd

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I think I can guess which board though I won't name it either. They were inhospitable enough to me that I decided I didn't need their sh&* and moved on. I have asked that they take down some tech of mine while I'm at it.

If all you wanted to do was truss the housing then a properly constructed tension rod running from C bracket to C bracket that is firmly located on the lowest point of the housing (but not welded to it) makes the most engineering sense. Steel is best in tension. If you want the ideal above axle truss you'll have to figure out how to make it from concrete. If made from steel it will have to be far, far heavier than an equivalent under axle truss.
Unfortunately the real world interfers with that ideal layout. I'll second Blue Coyote's advice.

TS

I used swerve around my halucinations, now I drive right thru them.
 

AaronDixon

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Below the axle trusses are always going to be stronger. The reason being the span of the truss itself. Below the axle, you can extend the truss to the end of the housing. Above the axle, at best you can only go to the spring pads. The reason why below axle trusses don't work is ground clearance. We ran a truss below the axle on our stock mini ranger and it would do more harm than good. You hit a big rock and not only does the truss get bent up, but it will actually bend the rear-end from the truss tubes pulling the pumpkin and the end of the housing together. We have gone to an above the axle truss to maximize ground clearance.
 
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