Calmini rear bumper & SEMA truck

[rrdstarr]

So those (blue) swaybars connectors are for a lifted Xterra?

[xoc]

Yes, they're longer than the stock ones, and part of the kit.

You can see them here...

[rrdstarr]

I wasn't 100% sure, but suspected that is what they were!

[ned946]

Originally posted by Schludwiller
Thanks for the update Ned.

This is the part that bugs me. That c-section coming from the frame can be bent with a hammer. I don't have a hitch, but isn't that why Nissan puts the frame strengtheners on? ]

I did have the hitch and I do have the rail stiffeners, they are in there.

One thing that bothers me about your argument is that it is really directed to Nissan, not Calmini. Its Nissan's frame and design. I think that some of your ideas would improve things, but only ever so slightly. If things are to fail, it will be at the level of the frame, not the bumper. You can slide back stiffeners as far back as you want, but at that end point will, again, be the weak point (I would think) and the failure point.

I'm sorry but I don't think your argument is a real world argument.

And, too, I am not trying to flame, just comment honestly.

If someone wanted to do 'frame stiffeners', couldn't they just place some stock inside the frame and bolt it up? Same effect for less than a dollar?

[Schludwiller]

Originally posted by xoc


Simple. The truck is designed to show off Calmini's parts, and those sway bar end links are part of their kit.

Out of curiosity would you use their extended sway bar? Or is that designed for people that want the lift, but drive more onroad.

[Xlax]

Originally posted by rrdstarr
That is why this board works so well! Everyone contributes! Even Claus!

Hey wait a minute !....what the H E double hockey stick to ya mean by that??.....:finger: HOSER !

I love those blue shackles...just looking at mine sitting on my desk..hmm get a spray can???


Claus

[ChuckH]

Originally posted by ned946



I did have the hitch and I do have the rail stiffeners, they are in there.

One thing that bothers me about your argument is that it is really directed to Nissan, not Calmini. Its Nissan's frame and design. I think that some of your ideas would improve things, but only ever so slightly. If things are to fail, it will be at the level of the frame, not the bumper. You can slide back stiffeners as far back as you want, but at that end point will, again, be the weak point (I would think) and the failure point.

I'm sorry but I don't think your argument is a real world argument.

And, too, I am not trying to flame, just comment honestly.

If someone wanted to do 'frame stiffeners', couldn't they just place some stock inside the frame and bolt it up? Same effect for less than a dollar?

That's what I did on mine. I got some angle stock and ran it into the box section. However, without having the tools to bend and cut it's not possible to run them very far forward like the Nissan inserts do. I would rather have the Nissan inserts, but you can't get them without buying the hitch. The inserts don't really do much for the side of the frame and are there to strengthen the lower part where the hitch attaches. One of those attachment points is inside the frame section. Anyway, when mounting a tow hitch, the idea is to distribute the load and not put it all on the back of the frame. You're right that Nissan is responsible for the weak frame ends, but they also have a fix and there are easy ways to overcome that when mounting a hitch. I think the reason the frame is open at the end is probably for crushability in an accident.

KMA didn't put long enough inserts on either and that is why I had to build up the ends of my frame. Even so, it's probably not as strong as I would like it to be, but I won't know until I really load it up. Schlud had his mounts replaced so they go into the box section of the frame and utilize all six moutning holes (bottom and side) in the frame. After I got my bumper, I talked to several different fabrication and towing specialists about the attachment and all agreed that KMA blew it on the inserts and that a towing load needs to be distributed farther forward on the frame.

All that said, Calmini took a different approach. Obviously Calmini saw that the ends of the frame couldn't take much of a towing load so they developed the center mounting to put most of the load on the frame crossmember. That's fine, just strange to me. There really isn't anything structurally wrong with what they did as far as I can tell by pictures, but I just wonder why they went through the extra development work and everything when adding a few more inches of steel to the rail brackets would have served the same purpose and been more simple.

Anyhow, the bumper looks really sweet and I thank you for sharing the information and discussing it with us. Schlud and I are in no way saying the KMA is better, because it isn't...well, wasn't! It's just that wih all my years around metal fabrication and in talking with specialists in this area, I want to make sure nobody else gets screwed like I did with the KMA. Just enjoy your new bumper and let me ponder the reasoning behind the Calmini approach to load distribution!

[ned946]

What is this?

"IPF JO-1's"

[wilburburns]

Anything we can and do build at home is likely way overbuilt. There's a simple reason for this. We do not have sofisticated software to simulate the loads and structural fail rate of our designs. While Aftermarket companies can test and develop on PC's, we can't. []

When aftermarket companies such as Calmini put smaller parts, thinner steel, etc, it's because they are cutting costs and have determined exactly what size they need for their design strength. Calmini must have determined that the center Hitch support will be cheaper to build than lengthening the Frame inserts.

Now, I'm designing a rear bumper for my truck. It will be the thickest steel I can work with and will mount somewhat like the Modified KMA's. However, I expect this bumper to not fail ever. Likely, the Nissan Frame will bend and fail before the bumper will. I do this because I don't want anything I build to fail and cause an accident anywhere. We can all imagine what will happen if the receiver failed on teh interstate while travelling 70mph..[]

Now If I had all the software and knowledge to just design what I need, then things would be different. HMMM come to think of it, I work with several structural engineers....

Most importantly, Steel brackets are only as strong as the welds.

Cliff

[ned946]

wilburburns,

I totally respect home fab. I tinker a lot and I know you get the sense of accomplishment you cannot get by buying off the shelf. It should be a good project for ya. I'd probably tackle it too if I knew how to weld [ ] and I had a welder [ ].

One thing you might want to consider (not just wilburbrns) but Steve has told me again and again that he will talk to anyone on the phone and take the time to really answer your questions....and probably give you some inside info on whats next for the X! He has said that he really prefers calls to e-mails though.

You might want to hit him up on design concerns and why he did what he did?!?!?

[wilburburns]

Ned, You probably don't know, but I actually own a truck..A Frontier...

I was just commenting on mounting brackets and etc...I mentioned KMA, because they seem to be the equivalent of home fabrictaion, while Calmini is a larger operation. That's where the comparison comes from.

Also, Chuck has modified a good strong KMA design. (the design was good, but quality obviously was not) So I was also referring to him as a home fabrication. Although, It sounds like he does have experience in fabrication, but I don't think he's got the necessary programs or schooling to calculate exactly what is needed for the designed purpose and intent. Therefore, Both the KMA and Chuck's modifications are overbuilt. :frog:Chuck, Feel free to correct me if I'm wrong.

I'm not Flameing anyone here, just trying to give a small voice of reason and opinion. I do question both design if being pulled from the rear at an angle. Possibly being winched backwards and not on a straight pull. This will cause a twisting motion. But again, which will fail first the Bumper or the Frame? :smoka: I don't think anyone really wants to find out...

BTW, My design has everything the KMA and Calmini have. Integrated Receiver hitch, Either shackle mounts or attached D-Rings, Will beable to lift from it, and hopefully a it will be sealed for use as an Air Tank. But I don't need the Tire Carrier. realistically, the tire carrier is the easiest part to build, but makeing it work with the Hatch is not so easy.

Cliff

I'm still purchaseing all the necessary equipment, so don't expect to see my design anytime soon. I'm just learning to weld, but I have several experienced people to look over my work for strength and looks. Mostly strength, because clean welds just come with time..

[Schludwiller]

Originally posted by ned946
What is this?

"IPF JO-1's"

They're integrated driving and fog lights from IPF. Check out Chucks thread "let there be light".

[Schludwiller]

Originally posted by wilburburns
. Likely, the Nissan Frame will bend and fail before the bumper will.

Cliff

Reminds me of the last thing the guys at the welding shop said to me. "The rear end of the truck will get ripped off before this bumper does."

You mentioned twisting. I used my bumper this weekend and pulled from the center hitch with Chuck's receiver tow hook. Mainly because I want to distribute the load as much as possible. Also I was on a muddy section between trees and didn't want the stock truck I was pulling up to slide me into them.

I have two D-rings on each side, but I'll probably use them in specific situations that require off angle pulls. When I did damage to my door getting extracted all I could think about is if I had that damn bumper sitting in my garage I could have gotten out (It still had the short inserts and I was waiting to fix it).

[Philosopher]

Originally posted by Schludwiller


Out of curiosity would you use their extended sway bar? Or is that designed for people that want the lift, but drive more onroad.

I think that they made that an option for folks like Carlton. I guess this would be for folks who can "really feel a difference" in the way their truck rolls around corners and stuff on-road. I can tell a small difference, but I simply changed my driving habits slightly. I ripped out the rear swaybar more than a year ago and haven't missed it a bit.

[ChuckH]

Originally posted by ned946
What is this?

"IPF JO-1's"

Yep, IPF JO-1's would be these. Round 55 watt fog and driving dual beam lights. Pictured with fogs on.