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approach and departure angles

Discussion in 'Center Of Gravity' started by four_by_ken, Dec 16, 2004.

  1. four_by_ken

    four_by_ken 1/2 ton status

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    Lets put body changes aside in this thread.

    Obviously the best way to help the angles is by a link suspension, that way there is nothing behind or in front of the vehicle.

    But, how about with a traditional leaf suspension? How can you increase your approach and departure angles? I realize there is only so much you can do... but what CAN you do?
     
    Last edited: Apr 15, 2009
  2. blk87K5

    blk87K5 1/2 ton status

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    One thing we have done in the past on some of the rigs built around my place is to go full hydro and cut the front of the frame off. If you are happy with your wheelbase, it is a good option for trail rigs. This does entail tube work to restore integrity to the frame, and bodywork to gain the full advantages.
     
  3. four_by_ken

    four_by_ken 1/2 ton status

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    Except when you have leaf springs... you can only cut to where the spring hanger\shackel is.

    Not much.
     
  4. 6.2Blazer

    6.2Blazer 1/2 ton status

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    With the amount of lift you have mentioned before and 44's, you should have a really good approach angle on the front. I know with a 4" lift and 38's the approach angle is rarely a problem. The back is another story for me but I also have the factory trailer hitch still installed. Again for you, the lift and tire size will really help, especially if you move the axle back an inch or so and have a nice tucked-up rear bumper. I'm not really sure what else you could do on the back without bobbing the body, relocating the fuel tank, and hacking the frame off just behind the shackle hanger.

    A link suspension really wouldn't help any unless you also stretched out the wheelbase front and rear. By looking at a good side profile shot of my Blazer it looks like you would hit the body before you would ever hit the front spring hangers......same goes for the rear, the rear bumper, body, or frame would hit before the shackle hangers.
     
  5. four_by_ken

    four_by_ken 1/2 ton status

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    Yeah, I hope I am in good shape. I have my winch tucked between the frame rails, and the bumper up close to the body. And the rear bumper is as close to the body as I could get it and still be able to open the tailgate and not hit the bumper with it.
     
  6. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    First, you cut the frame to the hanger or more the hanger to the end of the frame. Then make sure nothing else sticks out past that. Hate to be captain obvious, but anything sticking out is putting a limit on you. You can see what I did to avoid it.

    Second, figure out if you can move the axle on the spring toward the ends. This asymmetry causes changes in behavior like increased axle wrap and pinion rotation in travel. It also causes increased bind through the axle housing as each spring wants to torque the tube in opposite directions when twisted.

    Third, figure out if there is some way to use a different leaf and/or mount to achieve the same flex with less overhang. That's how I wound up with my reversed 57" springs. However, that impacted lots of other stuff I had to deal with like axle wrap and pinion control (it rotates exactly opposite what you want). To fix that I had to add an anti-wrap bar and use "Springer/AK57" shackles to let the short end (now in the rear) swing down, simulating a much longer spring like the 63"s.

    Down side is that the rear springs don't last me any time at all any more since I kinda got interested in "climbing waterfalls". Worked fine and lasted a fair number of trips till I started trying some of the really nasty climbs.

    But, I got nearly 90* out of leafs. Not sure the ultimate performance and trade-offs were worth it though. It's sure helped in a few cases where any longer "departure" angle would have made things much worse for me, but I doubt I would work so hard to get it again. If you really care enough to go to that much trouble, save that wasted time and trouble by going links as I am.
     

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