Register now to get rid of these ads!

Technical I need shock mount ideas - FINISHED PRODUCT

Discussion in 'The Hokey Ass Message Board' started by TA DAD, Aug 29, 2020.

  1. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,216

    2OLD2FAST
    Member
    from illinois

    The closer to the unsprung weight the shock mount is , the better able the shock will be to control that weight .
     
    gnichols and grumpy65 like this.
  2. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Angling shocks will also affect the velocity of compression. Slowing the velocity will allow the shock to do it's job better, giving a smoother ride.
     
    2OLD2FAST likes this.
  3. gnichols
    Joined: Mar 6, 2008
    Posts: 11,345

    gnichols
    Member
    from Tampa, FL

    Shocks and coil springs do not change their rate (stiffness) even when mounted at angles. Even in the box they are the same. What they loose is their effectiveness.
     
    Last edited: Sep 30, 2020
  4. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Found it. This is an amazingly informative reply from an old thread.
    Post was by @Rat L. Can .



    Regarding your question as to why shocks are sometimes mounted on an angle.

    Short answer is: for packaging reasons mostly.

    Long answer is, well, a very long answer...

    First, shock absorbers aren't even shock absorbers, they're dampers. Contrary to popular belief, they don't simply control the wheel/axle assembly when disturbed but actually "dampen" the entire vehicle in a variety of modes. So it's important not to think of a "shock absorber" simply controlling 1 wheel; the front has a contribution to the rear and vice-versa. In other words, you need to think of them as a "system" each contributing a certain amount of control/stiffness to vehicle.

    First, each vehicle has a unique frequency and stiffness determined by tires, springing, wheelbase, chassis stiffness, etc. Each one of these factors contributes to how the vehicle PITCHES (see-saws about its centre) and HEAVES (bounces up and down vertically). These modes are active whenever the vehicle is moving and occur at different frequencies to each other.

    The damper's job is to minimize the amplitudes of these modes in order to reduce load variation (better traction) and minimize disturbances (better ride quality). It should be noted that these resonances occur at very low frequencies~ 4 to 6hz (or 4-6 times per second). However, they are quite important to how the vehicle behaves and "feels" to the occupants.

    Now, the next thing the dampers do is influence the response of the vehicle. A key thing to remember is that dampers are VELOCITY sensitive, not displacement sensitive. They have to be moving in order to work and they have no idea of how far they've moved. That's why we describe/measure damper forces in units of FORCE VERSUS VELOCITY. So a typical road car damper is then built to achieve a certain amount of force for a given shaft velocity. This is tested using a shock dyno over a speed range of 0 inches/second to more than 20 inches/second. (Off-road racers test at incredible shaft speeds, over 20 FEET/second!)

    The vehicle's handling response is mostly influenced by the low-speed compression force in a given damper. This force is generated at very low shaft velocities~0-1"/second. From there the forces "ramp up" to a given/desired force that is typically defined by ride-engineers in real world road testing. This would be in the 1"/sec to 5"/sec velocity range. This range is important as it contributes a lot to the perceived ride quality. Too soft and the car just wallows, too stiff and you get a very harsh ride like a steel-wheeled skateboard.

    Above velocities of 5"/sec is where the majority of the pitch and heave cancelling occurs. This is usually developed using a 4-post shaker rig where the vehicle is excited over a decaying sine wave of varying frequencies and amplitudes. (Usually starting at large amplitude/low frequency and the "decaying" to high frequency/low amplitude). This rig allows a known, measureable amount of "energy" to be introduced into the vehicle. Sensors then return the amount and amplitude of disturbances that the vehicle sees. From there, dampening is finely tuned to minimize these variations.

    So, in summation, it's a very complex relationship and there is no simple answer as to which damper you should use and at what angle it should be mounted. Barring some very expensive testing equipment, my advice would be simple trial and error. Just remember that adding more angle reduces the damper's velocity and and they need velocity in order to work.


    I hope this helps your understanding a bit and I must add that this screed only begins to scratch the surface of dampening's contribution to vehicle performance.
     
    Last edited: Aug 29, 2020
    gnichols likes this.
  5. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Very well put. The spring rate does not change.

    Angling reduces the effectivness of the spring in relation to vertical. This needs to be taken into account when calculating effective spring rate for the suspension package.

    Just remember, the spring does all the physical work. The shock is purely there to "dampen" the action of the spring.
     
  6. upspirate
    Joined: Apr 15, 2012
    Posts: 2,299

    upspirate
    Member

    Question... Wouldn't it be better to have the shock mount stud going fore and aft instead of cross wise like this? Seems like this would bind more. I know the stud slides through a rubber bushing, but it would seem to work easier if it could rotate on the stud. Also it wouldn't put as much stress on the bracket and bolts
     
  7. Pete1
    Joined: Aug 23, 2004
    Posts: 2,253

    Pete1
    Member
    from Wa.

    Another thing to consider is the orientation of the shock (I know, it's a damper), which most people never think of.
    Usually reducing unsprung weight is good. Take a look at most modern race cars, the shocks are mounted shaft DOWN. It DOES make a difference if handling is a required parameter.
    Keep in mind though, you can't just turn any one over. They have to be designed to run that way. Most race shocks are. Race shocks are also available in far wider ranges of compression/rebound.
     
  8. All theory aside, this is not a road race or slalom rod, the first consideration is the shocks need to be mounted so they don't interfere with other components. If the component layout allows some flexibility in shock mounting, that would be good.
     
    alanp561 and grumpy65 like this.
  9. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    As far as I know, if the top and bottom studs are parallel to the axle, the shocks need to be vertical when viewed from the front/back. The shocks can be angled forward or backward when set up like this.

    If the shocks are angled in at the top, as in the case of following the axle's arc of travel, then the mounting studs should indeed be perpendicular to the axle. This would be a simple modification to make to the bracket.

    If we really get into it, there is an "arc of travel" present when viewed from the side as well. The wisbones/4 link/hairpins/etc all describe an arc around their rear mounting point. In reality, it will always be a three-dimensional dance during suspension travel.
     
    clem and upspirate like this.
  10. Here are a couple examples I found. shock1.gif shocks2.jpeg

    Phil
     
    grumpy65 likes this.
  11. Here is one more. Right or wrong, these all have the shock rather vertical. Hope this helps. shocks3.jpeg

    Phil
     
    grumpy65 likes this.
  12. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Agree totally. We are getting a bit too far towards race application here.
    I don't think the angle would amount to any noticable difference in this situation. If it were me, I would put a little angle into the system. It seems from the original pics that there would be limited available space. If the tops can be in 10 to 15 degrees I would be happy. Mainly for asthetics, but who knows, maybe a little advantage would be had.
    Like I said previously, it can't hurt. ;)
     
  13. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    [​IMG]

    This is good. A little in at the top just looks right.
     
  14. Pete1
    Joined: Aug 23, 2004
    Posts: 2,253

    Pete1
    Member
    from Wa.

    You would use a light tube axle, light disc brakes and aluminum wheels to reduce unsprung weight but not turn the shocks over????
     
  15. Almostdone
    Joined: Dec 19, 2019
    Posts: 892

    Almostdone
    ALLIANCE MEMBER

    Pete and Jake’s kit on a Model A. Goes with most of the discussion thus far.

    C24FD417-6D18-4E4B-AFBA-67F51AA60FE6.jpeg
     
  16. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    I am not going to argue with a mechanical engineer, but will point out that my comment about the picture was singularly regarding the slight shock angle and the resulting "look" acheived. The light weight tube axle, light disc brakes, aluminium wheels and turning the shocks over are worth consideration, but not in the context of my post.
    :rolleyes::rolleyes::rolleyes:
     
    upspirate likes this.
  17. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Here are some pics for inspiration.

    For shaft parallel to axle.......

    [​IMG]

    [​IMG]

    If you want the shaft perpendicular to the axle, make them like this (front sections only)......

    plates.jpeg

    Angled or vertical ???? Entirely up to you. Design and fabricate as required. :D
     

    Attached Files:

    Last edited: Aug 30, 2020
    gnichols and upspirate like this.
  18. upspirate
    Joined: Apr 15, 2012
    Posts: 2,299

    upspirate
    Member

    Yep as far as shock angle and stud orientation, but not to the op's situation as to how to attach the lower mount. He has parallel leafs, not transverse with wishbones
     
    grumpy65 likes this.
  19. Joe H
    Joined: Feb 10, 2008
    Posts: 1,525

    Joe H
    Member

    Here is a how my '37 Chevrolet pickup has the front shocks mounted. Simple mount under the u-bolts and heavy steel welded to the frame. I have since moved the top mount forward using a second piece of steel mounted to the first piece. I went 20% forward to reduce the efficiency. It made a noticeable difference in ride quality. It was way stiff when straight up and down, now it has more " give " when going over rough roads.
     

    Attached Files:

    pprather and grumpy65 like this.
  20. TA DAD
    Joined: Mar 2, 2014
    Posts: 1,107

    TA DAD
    Member
    from NC

    Well here is the finished product. I ended up using just the front u-bolt due to clearance issues. Bent up a piece of 1/4 in. plate and put a gusset at each end. I used a couple small tabs for the top mount. Welded it all up ( I am about blind so don't look to close ) and call it done. Final cost was about $16.00 and several hours of my time, which is all I got studebaker build 018.JPG .
     

    Attached Files:

    pprather, leon bee and gnichols like this.
  21. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    They will do the trick nicely, and look like they are meant to be there.

    Time well spent. Good job. :)
     
    pprather likes this.
  22. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    [​IMG]

    Hey @ TA DAD ,
    I am trusting that you used a proper shock stud that is manufactured to do the job.
    Also, you are going to tighten the nut up, right? I am assuming it is like this due to the pic being taken at pre-assembly stage, prior to removal for painting. ;)
     
  23. TA DAD
    Joined: Mar 2, 2014
    Posts: 1,107

    TA DAD
    Member
    from NC

    Yes , the stud is the one that came with the shock. Yes again I did tighten the nut. But there will be no paint.
     
  24. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Thought you would have it all under control. :cool:
     
  25. TA DAD
    Joined: Mar 2, 2014
    Posts: 1,107

    TA DAD
    Member
    from NC

    Thanks for your input grumpy, I believe they will hold up. And built is better than bought for this project. It would have fit the Crude Modification thread.
     
    grumpy65 likes this.
  26. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

    Any chance you can take a couple of steps back with the camera and post some pics of the whole deal. You have me intrigued...............
     
  27. TA DAD
    Joined: Mar 2, 2014
    Posts: 1,107

    TA DAD
    Member
    from NC

    Here is one from a several months back. The shot from the front is fresh with the front shock mounts. The front end is done, all new tie rod ends, king pins are nice and tight. N.O.S. steering box. And my greatly improved pitman arm mount. Plus the disc brakes. New bushings in the front springs. It was surprising how sensitive the u-joints in the steering shaft were to get them dialed in with no tight spots. But it steers as smooth a silk on the stands. The only thing left to do is add a cotter pin on the drag link bolt. The factory mount was a gusseted piece of angle iron with no support on the outer end and it wanted to pivot on the frame when you turned the wheel. I added the lower angle bolted to the side rail to eliminate that. Plus the support for the end of the bolt. studebaker build 025.JPG Spring 2020 042.JPG studebaker build 013.JPG
     
    grumpy65 likes this.

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.