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Axle truss idea

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jarheadk5, Sep 20, 2000.

  1. jarheadk5

    jarheadk5 1/2 ton status

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    I've been thinking about this for a bit. An under-the-axle truss will get snagged on stuff, so why not try an over-the-axle truss? Ideally, it would run from the backing plate flange at the end of the tubes to the centersection and be welded on (carefully, of course). The spring perches would be incorporated into the truss. I'm pretty sure the rear wouldn't be too much of a problem, but what about the front? Would having front spring perches maybe 2" higher than stock be like front blocks (i.e. a dangerous no-no)? I'm just brainstorming here, trying to think of ways to strengthen a 10-bolt somewhat. Feel free to poke holes in my theory.
    Please don't hit me with the "go with a 14-bolt" line...

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  2. jcg

    jcg 1/2 ton status

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    Most race trucks run a rear axle with a truss on the top, it works really well. As far as the front axle, I'm not sure. The reason you don't run blocks up front is because the increased distance from the axle to the spring creates really bad axle wrap which in it's self is bad, but also can make the blocks come loose. If the perches were raised you wouldn't need to worry about them coming loose but it would still give you a lot of axle wrap. I've seen front trusses that bolted on to the top of the axle, over the springs, so they can be removed if the axle has to come out. I'd like to truss my rear 12-bolt but I hate welding on cast parts. Has anyone seen, or tried making, a truss that welds to the tubes but just goes over the diff? I think it could work.

    Joe
    RIT Mini-Baja http://www.rit.edu/~bajawww
    Team Mudnuts http://www.mudnuts.org
     
  3. Goose

    Goose 1/2 ton status

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    My theory: If the axle is going to bend it will be at weakest point. That would be next to the differential. If you weld a truss from inside of one spring perch to the other spring perch that should solve most of the problem. You wouldn't need to attatch to the cast differential if your truss is solid enough. This would make the outer 4-5" of the axle tube the weakest part. Since this is very short in comparison to the spring perch to spring perch span you solidified, it would hold up well.
    Like I said, my theory. I haven't seen a top front axle truss nor have I heard any pros/cons to them.
    Theory is based on where your forces that bend the axle are coming from. Basically the sping perches are being forced down while the axle ends are being forced up. When the axle fails (in the middle), the distance between the spring perches is shortened on top and lengthened on bottom. The truss keeps this from happening amoung other things.
     
  4. Wheels

    Wheels 1/2 ton status

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    The idea behind a truss is to put a preloaded tension on the area (axle tubes) to re-enforce that area. An above the axle truss would work but the tension would have to be reversed. The best way to accomplish an above the axle truss is to cut a profile of the axle from plate steel in a continous piece and weld it along the length of the axle. Otherwise the axle would be spring loaded to catostrophic failure.
     
  5. Rockblazer

    Rockblazer 1/2 ton status

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    I am going to use a rear truss on the top of my... 14 bolt. My reasoning... I am grinding the bottom lip off of the casting all the way to the diff cover bolts! Yucko you say! You ain't kiddin! I am doing this to get maximum ground clearance. So in theory I believe I have now weakend the casting a wee bit. Thus the top truss. Like it has been said, it could only help. The front is a different story. You run outta room fast when you talk in the front. Plus I don't like the idea of raising the spring perches any higher. You could go between those though, as it would probably be enough. I have to get some pics developed of the rear one that I saw done in a shop. Really turned out nice. It can only help. And all in all, unless you are planning on jumping the truck, it should be alright. By the way... why don't you just get a 14 bolt? Kidding! Todd

    "You're right... I don't understand that Jeep thing!"
     
  6. jcg

    jcg 1/2 ton status

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    Your right about running out of room in the front, that's what I forgot to mention. The truss I saw was on a truck with about 12" of lift so there wasn't really much chance of the it hitting the engine cross member or steering linkages.

    Joe
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  7. BurbinOR

    BurbinOR 3/4 ton status

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