Second Generation Nissan Xterra Forums banner

1 - 20 of 23 Posts

·
Registered
Joined
·
1,135 Posts
Discussion Starter #1
So with a new Xterra on the way (can't happen fast enough:bounce:)), I'm starting to think about the normal things any owner should be thinking: Skids, sliders, bumpers. I've been looking at the usual suspects as well as the one off stuff in other members build pages and it brought up some questions:

I see all this 3/16" plate and 1" thick recovery points bolted all over our rigs and I guess I'm having a hard time understanding why.... I can kind of understand the skids being so beefy but what about the other stuff? I mean, what are our frame rails, .120 wall at best? From what I can put together 3/16" plate bumper with 1" thick recovery points bolted to much thinner walled frame rails vs. unmovable object = Plate bumper looks great, frame looses. I don't see that as a good thing. Can anyone who has more knowledge than I do chime in here?

I am by no means bashing anyone's product or fab job here, just asking for some help understanding why we do what we do. I'm just as guilty here, I made my sliders out of 2"x2"x3/16" tubing on my '06 because thats what I saw everybody else doing. I do remember thinking it was weird welding the much thicker sliders to the much thinner frame at the time...

Maybe I'm totally wrong here? Please explain why. With the already bad mileage we get plus how spendy it is to have all that plate steel shipped to our doors, I feel this is a valid question:eek:ccasion5:
 

·
Registered
Joined
·
430 Posts
I mean, what are our frame rails, .120 wall at best? From what I can put together 3/16" plate bumper with 1" thick recovery points bolted to much thinner walled frame rails vs. unmovable object = Plate bumper looks great, frame looses. I don't see that as a good thing. Can anyone who has more knowledge than I do chime in here?
Strength is much more than just a function of how thick a material is. It has to do with geometry, stiffness, bracing, etc. The best example of course is a stamped unibody frame. While the steel itself is only a few mils thick, it becomes an incredibly strong and stiff structure due to it's overall shape. The whole becomes much more than just a sum of it's parts.
 

·
Registered
Joined
·
443 Posts
I'm sure a real engineer will offer better advice, but here is my understanding.

Its all about leverage and material strength/design. Think about the frame, it is thin relative to 3/16, but it's a lot larger than 1.5", 2", or even 3" tubing. Larger area material is stronger. Just like how a 1/4" or 3/8" solid steel rod is relatively weak, but a .065" wall 1" tube is much stronger, and a .065 wall 1.75" tube is stronger yet.

The sliders are generally made to hold the weight of one side of the truck, while sticking out a foot or so from the side of the frame, and spanning 5 feet give or take in length. Most only mount in 2 places, so they take a lot of abuse.

Also consider this, a tube is weaker once damaged, kinda like a soda can. You can stand on it when its solid, but the smallest dent will allow it to crush. If your sliders got a big dent right in the middle, next time you hit them on something they could fold in that weakened spot, if they weren't built like most are.

Same with skids, they need to be able to take some solid hits in relatively small areas. If they weren't so thick, a hit in the center of a plate would cause major damage to the skid, unless they were braced more, which then adds weight.

So through all this, there is no reason stuff needs to be this thick if you rarely actually needed it, I know some people have had components saved by the thin stock skid plates, but they are pretty much one time use(And not really made to take hard hits, anyway), whereas I don't think I've ever heard of anyone ruining a 3/16 skid(I'm sure it's happened), and some of the rigs on here take a lot of abuse.
 

·
Registered
Joined
·
1,135 Posts
Discussion Starter #4
I hear you guys and I do get the basics of angles and leverage. I guess my questions should have been more directed at the bumpers in particular. This is all fresh in my mind since I recently did some frame damage.

Just about every plate bumper I've seen on this site that took a good hit has bent the frame horns/mounts and yet the bumpers all seem to look like a fresh coat of paint would fix them right up . With that said, I ask you this: Are the plate bumpers we buy/make just a "because we can" deal or genuinely built that way out of necessity?
 

·
Registered
Joined
·
604 Posts
What our X's need Vs want you want is based upon how you wheel.

If you take regular weekend trips climbing major rock obstacles or if youre just a dude wanting to bring the X on the beach than you modify your X accordingly. Also off roading is not generally a time trial event, meaning people go slow and bumper impacts are mild.

Want to see what a fully armored steel bumper will do? YouTube has a few good ones with Xs at Moab dropping off the wall on "steel bender"

Approach angle is also very key to the geometry of most tube/plate bumpers too



Sent from AutoGuide.com App
 

·
Registered
Joined
·
1,135 Posts
Discussion Starter #6
This thread is not going where I'd hoped. I understand needs and wants and that a big thick plate bumper is great for hitting rocks and trees. I also am very aware of the advantages they give in the approach and departure angles. My X has the scars on the stock crap to prove it.

Think of it like this: 500lbs of steel plate bolted to the front of an X will surely drop off a waterfall with little or no noticable damage, Right? What about 300lbs? 150? 100? This was meant to debate the size/weight of the common bumpers we install on our rigs. If a 3/16" Shrock will take a licking would a 1/8" Shrock still do the same job and save some weight?

To me, if the bumper is still mint after a impact but the frame horns bent and the still intact bumper got pushed up into the headlights and fenders, it seems that the bumper is over built. The bumper should be toast first if there is any other damage to the front end in my opinion.

Am I explaining this any better this time? Not trying to be an ahole here, I swear. As I'm reading what I just wrote, it kinda looks like it but, it's not my intention at all:eek:ccasion5:
 

·
Registered
Joined
·
6,919 Posts
Want to see what a fully armored steel bumper will do? YouTube has a few good ones with Xs at Moab dropping off the wall on "steel bender"
Psssh! Head over to NEXTerra, look up BKxterra718 and find out how he bent his Shrock :)


Back on topic, Mr_Scott, one thing you might consider is that a lot of independent bumper builders out there are not engineers, operating on the simple principles of beefy = strong and strong = good (and I'm admittedly generalizing here). The ability to weld does not make one a mechanical engineer - I make no such claim for myself, but as a welding instructor I see a lot of inefficient/overdesigned (but very strong) work. And hey, I'm occasionally guilty of it myself, but if it's the difference between something bashing somebody on the head or staying exactly the hell where I welded it, I'm going to opt for the latter, but only because I don't have the knowledge/equipment to do something better.
If you look at ARB, they manufacture bumpers that actually have impact absorbing components added during construction, and their designs are layered. Watch this video: http://www.youtube.com/watch?v=3yqHL7Uo4_s&list=TLLK7UUNE6oqE

ARB bumpers would fall into the "engineered" category of bumper design (and IMO, is probably more worthy of being properly called a "bumper"). Meanwhile, let's look at how Shrock builds their bumpers:




See all those grind lines? Indicative of the bumper being built from many separate plates welded together (granted these images are both prototypes, but many independent bumper fabricators use this construction method). Now, any welder knows that the (proper) weld is always stronger than the parent material, so it can logically be concluded that welded seams, reinforced at logical points, are at least as strong as, if not stronger, than strategically bent and supported material), so it's okay to have so many fully welded panels. Regardless, the construction of the Shrock is more comparable to a plow (which pushes things out of the way) than a bumper (which absorbs impact). Shrocks are more design than engineering if that makes sense - they're designed to look good, they're designed to take a hell of a beating. They're not engineered to transfer the force of impact, they're designed to simply take it and move on.
 

·
Registered
Joined
·
1,135 Posts
Discussion Starter #8
Thanks man. This is exactly what I was getting at. You did a much better job eloborating than I could have.

So you may not be a engineer but you do play with a lot of material. I think this makes you pretty qualified. Do you feel that our current plow:D options are maybe overkill for what they are ultimately attatched to? Is the standard 3/16" the magic thickness for an Xterra in your opinion?
 

·
Premium Member
Joined
·
22,508 Posts
I've already bent and buckled my 3/16" steel bumper at less than 5mph against a rock on a trail. I also have several major dents and bends in my 3/16" steel skid plates. If I ran 1/8" it would be worse. But, I actually wheel. If you will mall crawl, 1/8" bumper is fine, and skid plates are completely unnecessary at all.
Posted via Mobile Device
 

·
on line
Joined
·
1,431 Posts
But, I actually wheel.
:laughing3:
The most overused phrase on this site. If you looked at his avatar, you'd realize Mr_Scott "actually wheels" too. Why would he want skids if he's a mall crawler? He was asking a simple question and you gotta act all high and mighty.
 

·
Premium Member
Joined
·
22,508 Posts
:laughing3:
The most overused phrase on this site. If you looked at his avatar, you'd realize Mr_Scott "actually wheels" too. Why would he want skids if he's a mall crawler? He was asking a simple question and you gotta act all high and mighty.
I'm on my cell, so I can't see his avatar. I simply spoke the truth. I'm not acting high and mighty, though it doesn't get any more ironic than YOU telling someone they are acting high and mighty. Lol
Posted via Mobile Device
 

·
Registered
Joined
·
6,919 Posts
Do you feel that our current plow:D options are maybe overkill for what they are ultimately attatched to? Is the standard 3/16" the magic thickness for an Xterra in your opinion?
Well, I had a factory radiator skid on my X (I'm pretty sure all Xterras come with them but correct me if I'm wrong). Those things are, as the other factory skids, rather thin and come from the factory with many bends. If you grabbed one from both ends and twisted, it wouldn't bend as easily as a straight piece of steel of similar thickness, but if you bash it with a rock it'll still cave. Funnily, the way the factory skid mounts (to the bumper) actually gives it a limited degree of impact deflection since the bumper is flexible - can't guess at how intentional that is.

I later upgraded to a used Hefty skid, which was actually slightly bent when I received it (but it was free so I rolled with it - I don't think I'll ever wheel hard enough to justify getting myself a new one). Compared to the factory skid, the Hefty really only mounts in one place (the tow hook nuts) and transfers energy in a different way (directly to frame). Again, it sort of follows the design principle of "take it and move on." While the Hefty is designed for the stock bumper cover to bolt into it, it's more of a formality/convenience than any intention to create a transfer of force. I actually left my bumper cover free-floating so it would flex more in a light impact such as brushing up against a tree.

3/16" seems to be the industry standard for any skid or armor. As with everything, the more (or less) of something you have, the closer you get to the point of diminishing returns, i.e., more liabilities are created than benefits. In terms of vehicle protection, if your armor is too thin it may as well be stock, but if it's too thick you're going to see a significant impact to vehicle performance, not to mention ground clearance (as awesome as a 1" skid might sound, you really don't want one of those hanging from the bottom of your truck, much less be the chump who has to install it). I don't develop offroad armor for a living, so I'm going to assume that people who do have collectively decided that 3/16" works out best in terms of cost, labor, manufacture, and quality. (Cost, of course, probably the main motivating factor - the thicker you go, the more specialized/expensive equipment you'll need to work with it)

That all said, Hefty has put out some feelers for an aluminum-skinned version of their bumper. Might be great for casual wheelers and mall crawlers. The issue with aluminum is that it's quite soft (unless you want to spend a lot of moolah on the more durable alloys. Aluminum is a third the weight of steel, but you'll need three times as much to get a comparable strength. It'll be interesting to see how that product develops.
 

·
Registered
Joined
·
1,135 Posts
Discussion Starter #13
Craig:
Thanks for having my back while I'm not looking. :eek:ccasion5:

SnS:
No offense taken. I try to make it out just about every weekend. Either on a day trip with the fam or a quick blast behind the house. I'm spoiled, I have access to everything from 2wd dirt roads to full on buggy canyons 2 min from my house. I plan on using the new wheels even harder than the last one. I can't wait to see the new places the locker is going to take me!

I've seen your posts so I do value your opinion here. If you are saying that what you have seems about right, then that means something from a owner who I know uses his rig in a similar fashion.

P1:
A welding instructor who is buying skids!? Blasphfamy sir!:D

I think I'll most likely be doing the 3/16 skids since I can see the need for the beef here. I'm still on the fence about the front bumper. I've seen guys try to make tube bumpers that end up weighing more than plate bumpers and prob do not provide the same protection. I guess I just want my cake and to eat it too.
 

·
Premium Member
Joined
·
22,508 Posts
Craig:
Thanks for having my back while I'm not looking. :eek:ccasion5:

SnS:
No offense taken. I try to make it out just about every weekend. Either on a day trip with the fam or a quick blast behind the house. I'm spoiled, I have access to everything from 2wd dirt roads to full on buggy canyons 2 min from my house. I plan on using the new wheels even harder than the last one. I can't wait to see the new places the locker is going to take me!

I've seen your posts so I do value your opinion here. If you are saying that what you have seems about right, then that means something from a owner who I know uses his rig in a similar fashion.

P1:
A welding instructor who is buying skids!? Blasphfamy sir!:D

I think I'll most likely be doing the 3/16 skids since I can see the need for the beef here. I'm still on the fence about the front bumper. I've seen guys try to make tube bumpers that end up weighing more than plate bumpers and prob do not provide the same protection. I guess I just want my cake and to eat it too.
1: craig is a pompous self-righteous a$$-hole who can go fvck himself.

2: Here is an example of my 3/16" steel bumper. would thinner steel have been better? How do you think 1/8" or thinner would have performed?

Rock kiss at under 5 mph to the end of the bumper, where leverage is greatest.



Resultant mash into fender:



Buckled out bottom of bumper:



Fender denting from impact and clearly visible impact point on bumper wing.

 

·
Premium Member
Joined
·
22,508 Posts
Haha. I don't know enough about Craig to make that call.

Nope, I'd say 3/16" is just about right if that is the damage. Did it tweak the frame horns at all?
I've been around long enough to know his attitude.

As far as frame horns, no, thankfully.
 

·
Registered
Joined
·
1,135 Posts
Discussion Starter #17
I've been around long enough to know his attitude.

As far as frame horns, no, thankfully.
Great info man, thanks. I had no idea they would bend like that. I guess all the others I've seen have been more of a head on, direct impact.

Any problems with the winch ever tweaking the bumper?
 

·
Premium Member
Joined
·
22,508 Posts
Great info man, thanks. I had no idea they would bend like that. I guess all the others I've seen have been more of a head on, direct impact.

Any problems with the winch ever tweaking the bumper?
Nope. Winching has been great. No movement or flexing under load. The first Gen Heftys had some issues when recovering, but the second gen that I have has been great.
 
1 - 20 of 23 Posts
Top