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shock absorber angles

Discussion in 'The Hokey Ass Message Board' started by fat141, Mar 19, 2008.

  1. fat141
    Joined: Jul 30, 2006
    Posts: 1,576


    When starting from scratch to put shocks on the rear of my 41 (261 powered) Chevie PU I started to wonder how important the angles from perpendicular are. ie. front to back and side to side. Any takers on this one??
    Yep a search was done.Thank you for reading (now help):):confused::)
  2. fat141
    Joined: Jul 30, 2006
    Posts: 1,576


    nobody know or nobody interested?
  3. Da Tinman
    Joined: Dec 29, 2005
    Posts: 4,217

    Da Tinman

    No more than 20 degrees in any direction,, the closer to straight up the better.
    As the angles increase the effectiveness of the shock is reduced.

    Hope this helps
  4. fat141
    Joined: Jul 30, 2006
    Posts: 1,576


    Thank you, thats what I thought
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  5. 1950ChevySuburban
    Joined: Dec 20, 2006
    Posts: 6,210

    Member Emeritus
    from Tucson AZ

    I just went through this on mine......
    You can either go inward, or forward 20-30 degrees. NOT BOTH. either canted inward, like a Corvette, or angled forward (or rearward) like a GM truck.
  6. fab32
    Joined: May 14, 2002
    Posts: 13,990

    Member Emeritus

    The shock doesn't know whether it's going forward, sideways or any combination of both. The angle measurement is off of verticle in any direction that is convenient to mount them and there is clearance for them to travel without binding.

  7. krylon32
    Joined: Jan 29, 2006
    Posts: 4,719

    Alliance Vendor
    from Nebraska

    18 -22 degrees as the angle increases as the car settles.
  8. dana barlow
    Joined: May 30, 2006
    Posts: 2,754

    dana barlow
    from Miami Fla.

    strait up is best but over 20* starts to get week as stated above.
    In case your making mounts from scatch,the closer to the tires the shocks are mounted the better they work,shocks mounted in closer to center of axle get very week,this is seen a lot rods at the front & rear axle and they woneder why the steering gets the shakes .:eek:
  9. altraditional
    Joined: Dec 17, 2006
    Posts: 112

    from Estland

    I would also like to know, whitch would be better and why:
    When I have the truck arm suspension in the rear, should I mount the shocks to axle but at an angle (at least 30*) or put them somewhere in the middle of arms, pointing straight up, if I need a lot of travel?
  10. HotRodFreak
    Joined: Mar 25, 2005
    Posts: 1,934


    The angle affects the spring rate so more or less angle
    is better as appropriate to get softer or stiffer ride.
  11. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,777

    from Texas

    This is true only when talking about coil-over shocks, not regular tubular airplane or gas-charged tubular airplane shocks.
  12. enjenjo
    Joined: Mar 2, 2001
    Posts: 2,370

    from swanton oh

    Shocks are most effective when mounted the same as the direction of deflection. so in theory, you would mount them vertical. But of you do, they do not resist axle windup forces created by acceleration and braking, or side to side forces from body roll. Angling them forward helps resist axle tramp caused by acceleration, but not braking. Staggered shocks, one forward, and one back, resist both braking forces, and acceleration forces, as well as controlling bounce in the springs. And angling them in too, helps resist body roll, although the current thinking is to control body roll with a sway bar.

    Another reason for angling the shock, you can mount a longer shock in the same vertical space, so for every inch the axle moves, the shock may only move 7/8". This does make the shock less effective, but you can use a stiffer shock to compensate. On a light car, where most shocks are too stiff to begin with, this can work in your favor. This allows using a longer shock on a lowered car without limiting axle travel like a short shock would.

    The closer a shock is to the wheel is is controlling, the more effective it is, because the leverage of the wheel is less against the shock. When a wheel bounces, the fulcrum of the lever is actually the opposite wheel.

    The more a shock is angled to the direction of the foce acting on it, the less effective it is. Vertical to the force, it is 100 percent effective, 45 degrees to the force 50 percent effective, 90 degrees to the force, 0 percent effective. Most shocks are calibrated to be run at 15 to 20 degrees from vertical.
    Last edited: May 10, 2009
  13. blubomber
    Joined: Sep 7, 2005
    Posts: 27


    Interesting shock lesson, thank you. I just went through mounting tubular shocks on a 49 Chevy half ton. It originally came with lever shocks which, when not leaking, are great. However mine were bad and it is too pricey to rebuild them.
    When I adapted my truck I found a wrecked 51 Chevy truck chassis. That year (and later) had tubular shocks so I acquired the upper and lower mounts. The lower bolts on the axle u-bolts so figuring out location is not a problem. For the top I made a template from the 51 chassis hoping to use it on my 49. For some reason it did not work so I attached the mount about where it should go.
    If anyone is familiar with the upper mount you will see 4 mounting holes but only 3 are used with the lower hole sitting below the truck chassis. In my case I used all 4 holes which puts the shock a bit more vertical than it would have been on the 51.
    I was concerned about binding and such but I have driven the truck about 15 miles since and there appears to be no binding and the ride is good.
    I am hoping there will be no problem with them being mounted in a place other than the intended location. I cannot say if they are bottoming or topping out and would like to know how I can tell if they are.

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