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Weight of winch bumper. Formula for added weight.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Twiz, Jan 9, 2002.

  1. Twiz

    Twiz 1/2 ton status

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    I need to know the weight of a A.M. winch bumper or any other bumper, guesses are O.K. too.

    I found a way to figure out how much leverage over the front axle a bumper and/or winch will add.

    Looks like this.
    (W X (A + W.B.)) / W.B. = Weight the accessory is adding to the front axle.
    W = Weight of added accessory
    A = Distance that the accessory is in front of the fron axle
    W.B. = wheelbase

    Thanks

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  2. yeild2me

    yeild2me 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    if you say so!!...j/k....my KMA had a shipping tag with 172#, but that prolly included the skid it was on. so subtract the weight of your average, garden variety, rotten skid--say 30-40 #, so about 130 pounds

    hope this helps rob

    350 TBI, 700R-4, NP241, D44-14FF, 4:10's, 38.5 TSL/SX's, full conv., full cage
    <a target="_blank" href=http://www.yeild2me.rockcrawler.com>www.yeild2me.rockcrawler.com</a>
     
  3. Greenblazer-AZ

    Greenblazer-AZ 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    Well that depends on which winch bumper and with or without winch and which winch. Say that 3 times fast.
    I'd guess 50 to 500lbs depending.

    If you knew the truth, you too would be against marijuana prohibition!
    Blue '74 K5 Blazer Topless W/ 35 BFG Muds (See profile for pics)
     
  4. Twiz

    Twiz 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    I couldn't even read that 3 times fast.

    O.K., forget the winch. Just a guess at the bumper weight.
    I'm just looking for an average, thats all....

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  5. Twiz

    Twiz 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    This is what I'm getting at.

    Take yeild2me's numbers, 130 lbs for the bumper. Put it into the formula and you end up with 167 lbs over the front springs.
    Because, the bumper is not directly over the axle, it is in-front of it, so it has leverage. Leverage "adds" force.
    So, to make up for the extra weight of the bumper, the spring rate would need to be increased, not by 130 lbs, but by 167 lbs. (even more with a 100 lbs winch bolted on) - See what I'm getting at?-

    (W X (A + W.B.)) = weight the accessory is adding to the front axle.

    W = 130 lbs for the added accessory
    A = 32". Aporximatly how far in front of the front axle the bumper is mounted
    W.B. = 104" Wheelbase of a Blazer

    So it looks like this.
    (130 lbs X (32" + 104")) / 104" = 167 lbs


    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  6. 55Willy

    55Willy 3/4 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    so would it work the same for the rear bumper?? Thats something to keep in mind before we bolt on a 25 or so pound tire carrier with a 60 pound swamper and rim on it, add a 5 gallon can of gas and you'd have an easy 100#'s hanging off the rear..and if you have a custom rear bumper odds are it is heavier then stock.

    <font color=red>Life is like a mud hole:</font color=red><font color=blue>
    When the S#!T gets deep, you have to keep moving and friends can always pull you out</font color=blue>
    55 Willy's
     
  7. MR.GADGET

    MR.GADGET Registered Member

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    Re: Weight of winch bumper, even a guess is O.K.

    I have a warn with hooks and brush guard it's about 160lbs and with lights and 9500hs around 90-100 lbs additional so 250-260 or so

    IF IT'S NOT AS BIG AS YOU ARE DRIVE OVER IT!!!!!!!!!!
     
  8. blazen91

    blazen91 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    I built one for Toby(aka moneypit) and shipped it weighing in at 85 lbs or so. It was all .120 rectangle tube or 1/4" plate.

    <font color=blue> WHO SAYS YOU NEED BIG TIRES?? </font color=blue>
     
  9. Twiz

    Twiz 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    Yeah Fiddy-five [​IMG], it would work for the rear bumper too.
    Just measure from the rear axle back.

    The info is for snow-plows and such, but it works for us too.
    Makes you think twice about hanging or bolting on stuff to the very-front of truck. Every inch out adds to the weight (force) on the axle. But it doesn't add much, you really have to move the weight about 5 inches back to see any real differnce.
    Than you have that battery, up-high and in the very front corner. That sucker needs to be relocated some-where.

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  10. 55Willy

    55Willy 3/4 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    <blockquote><font class="small">In reply to:</font><hr>

    Than you have that battery, up-high and in the very front corner. That sucker needs to be relocated some-where.


    <hr></blockquote>
    Whats it doing up front...oh yeah I have the different body,LOL...mines going in the back...I need the front room for my OBA, and air filter set up[​IMG]
    BTW we did electric go karts at my high school and a battery is like 35 to 40 pounds. I'v heard enough of stories of those hitting the fan when the rusting tray gives out.

    <font color=red>Life is like a mud hole:</font color=red><font color=blue>
    When the S#!T gets deep, you have to keep moving and friends can always pull you out</font color=blue>
    55 Willy's
     
  11. m j

    m j 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    so you are saying it is lifting 30# from the rear axle?

    formerly 77chev
    still a jerk though
     
  12. Twiz

    Twiz 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    I'm not really sure m j. if it's takeing weight off the rear axle. (wouldn't think so)
    I'm just tring to make a point, that adding weight infront of the axle has the added leverage, and ends up multipling the actual weight.

    Really, all I wanted was some weights of winch bumpers.
    Thanks to the guys that have taken the time to replie.

    m j, dig the new sig! [​IMG]

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  13. Burt4x4

    Burt4x4 3/4 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    My KMA's shipping weight was 98lbs. It came wraped in plastic wrap so I doubt that added much to the shipping weight. I have a HS9500i in there and I think that was another 100lbs or so? I got a good 200lbs out front. Do you think the added weight is a negative or positive thing? Or our K5s are so tuff anyway it don't matter?[​IMG]

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <a target="_blank" href=http://coloradok5.com/gallery/Burt4x4>http://coloradok5.com/gallery/Burt4x4</a>
     
  14. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: Weight of winch bumper, even a guess is O.K.

    Yes, it is taking weight off the rear axle. That extra weight applied to the front axle has to come from somewhere, and that turns out to be the back axle. Otherwise, the sum of the weights supported by the two axles would not equal the weight of the truck as it must. Here, the front axle is acting as a fulcrum, allowing the forward weight to "lift" weight on the other end of the leaver. Basically it is just adding the new weight to that end of the truck and shifting the existing weight bias slightly more forward.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  15. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    Yep, just as BadDog said it would have to take weight off of the back. If you add 130 lbs. on the front it then increases the total weight of the truck by, well, only 130 lbs. If you increase the weight on the front axle to 167 lbs. by leverage, according to your formula, then you have taken 37 lbs. (167-130 = 37 lbs.) off of the rear axle.
     
  16. Twiz

    Twiz 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    B.D., 6.2, and m.j. (jerk)

    You think so? Is it transfering weight? I've been kicking this around all day. Still not sure, what you guys have said makes total sence.

    But....

    I'm kinda thinking "weight" is the wrong word to use. If you used "force" I think it would be more acurate.

    If you hld a, for example, a 12 oz beer can close to your chest, the force used to hold it is very little, but if you extend your arm all-the-way out. Than the force used to hold the can in the air increases, but it's still just 12 oz. The actual weight hasn't changed, just the "force" used to hold the can up has increased. -Make sence? Is that true? or am I "up-in-the-night"? Is there something I'm missing?

    Thanks guys. (I kinda dig this stuff)

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  17. Twiz

    Twiz 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    Burt 4X4;

    My opinon, I think it's not really a good thing to have a heavy front end. It might add stress to the front axle, and if it's a 1/2 ton, then it would bring the axle closer to it's maximum capacity. I wouldn't worry about that much, because 84 chevy k10 has never broken his front axle, and people use 1/2 tons for plow duty all the time, with-out brakeing anything.

    But from a "genneral" performance point-of-view, I think a lighter front would be better in most cases, except going up-hill.

    Best bet, keep the weight distribution 50/50. In my opinion.

    Yours, pluged into the formula ,useing the same specs, but changeing the weight, looks like this:
    (200 X (32 + 104)) = 232 lbs.



    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     
  18. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: Weight of winch bumper, even a guess is O.K.

    The "force" is still the same, it's just the gravity acting on mass. The only difference is your changing the leverage balancing that 12 oz against gravity by the length of your arm from your shoulder socket/fulcrum. Your also adding the mass of your outstretched arm. What your noticing is the additional "force" required to be expended against the lever in order to overcome the disadvantage due to increasing leverage of the downward gravitational force against your muscles. The total weight of the truck is divided between the two axles, that is just all there is to it. There is more stress placed on the frame, especially across the fulcrum of the front axle, just like there is more stress across the fulcrum of your shoulder joint.

    This is a simplification of static forces. However, there is some different kinetic behavior/effect when the chassis is moving due to inertial forces acting on that over-hanging mass. This inertial force applied across the lever might need more control from the shocks and, in extreme cases, might lead to a higher possibility of an endo.

    This is a radical simplification but, I hope it makes some sense.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  19. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    In this particuliar situation, the terms force and weight can be used interchangeably. Since BD already explained it, I will just add a quick note:

    If you weigh a truck, such as by putting it on a scale, you are measuring the "force" exerted on the four tires. If you put the whole truck (all 4 tires) on the scale it will weigh "x" number of pounds, let's say 6,000 lbs. for example. Let's also say that the truck has a perfect 50/50 weight distribution (equal weight on front and rear), so if you only put the front tires on the scale it would show 3,000 lbs.,
     
  20. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: Weight of winch bumper, even a guess is O.K.

    In this particuliar situation, the terms force and weight can be used interchangeably. Since BD already explained it, I will just add a quick note:

    If you weigh a truck, such as by putting it on a scale, you are measuring the "force" exerted on the four tires. If you put the whole truck (all 4 tires) on the scale it will weigh "x" number of pounds, let's say 6,000 lbs. for example. Let's also say that the truck has a perfect 50/50 weight distribution (equal weight on front and rear), so if you only put the front tires on the scale it would show 3,000 lbs., and by only putting the rear tires on the scale it would show 3,000 lbs. Then 3,000 + 3,000 = 6,000 lbs., the total weight of the truck.

    Now you add a 130 lb. bumper/winch on the front. The total weight of the truck increases by 130 lbs., so if you pull all 4 tires on the scale it will now read 6,130 lbs.

    Now by using yor formula (I haven't looked at closely enough to verify it, but the numbers seem reasonable), you say that there is 167 lbs. of force exerted on the front tires. So now, if you just put the front tires on the scale it should read 3,000 + 167 = 3,167 lbs.

    The total truck still weighs a total of 6,130 lbs. If there is 3,167 lbs. on the front, the remainder of the weight has to be supported by the 2 rear tires...so, 6,130 - 3,167 = 2,963 lbs. remaining. This shows that there is now only 2,963 lbs. of weight/force on the rear axle, which is 37 lbs. lighter than before adding the winch and bumper on the front.
     

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