SteveO

I'm looking at making another rear bumper, rock skis and a front bumper. One problem I'm faced with is I don't have a tube bender, so I'm considering making it all out of 2" square tubing 1/8" wall. I would assume that the 2" square tubing would be just as strong....


Anybody know the difference, such as weight, strength, etc.....

Robinhood150

Uh oh, you opened up a can of worms now!

On an academic basis, there is a difference in the strength and weight. However, on a practical basis, it doesn't matter for you since I don't think you're going to do the stress analysis. Everything we, as off roaders, build are over built and you're not trying to push the envelope for strength and weight like racing.

Soooo...for the average garage builder the strength and weight trade off is insignificant.

Robinhood150

BTW, did you see my reply about renting a tube bender in the off road section? You might want to consider making a bumper out of pipe instead of tubing.

MTL_4runner

UH OH........look out!......here come the engineers!
I'll keep quiet except to tell you use whichever is available/cheapest/looks good etc....
With 1/8" wall I wouldn't worry about strength.

BruceTS

I used 2"x 3/16 square tubing for the mounts and main rails on my sliders, then used 1-1/2" x .120 wall tubing for the outer rails.

For my rear bumper I'm gonna make the main bar out of 2" x 4" x 3/16 square tubing with 3/16 plate with 90 degree bends to attach to the frame rails. I just want to make sure it'll be as strong as the original tow hitch, since I will be towing my boat with it too.

Then I'm gonna use 11 guage sheetmetal for making the rest. I don't want to make it so strong that is doesn't bend at all, but it still has to be rigid enough to protect the body.

As for weight the square tubing will be a little heavier, strength should be about the same.

Mystickal

It depends on a lot of factors. Go here

The chart is broken down as follows:
case 1 - 2" square tubing, 1/8" wall thickness (baseline)
case 2 - 2" round tubing, 1/8" wall thickness (which makes it weigh less than case 1)
case 3 - 2" round tubing, same weight as case 1 (which makes the walls thicker than case 1)
case 4 - round tubing, same weight as case 1, 1/8" wall thickness (which makes it larger than 2")

The portion of the chart "% nor I of sq" is the rigidity (strength) of each case.

Hope this helps,

~Bill

waskillywabbit

iTrader: (-1)

Steve,

2" square tubing - generally starts at 3/16" wall but I guess you can get it thinner 3/16" wall weighs 4.32 lbs per linear foot

2" round pipe - SCH STD - little more than 1/8" wall and less than 3/16" is 3.65 lbs per linear foot

2" round bar - 10.690 lbs per foot

As far as strength goes, in general, carbon steel is going to have a yield around 36 ksi. I think for your application, a stress analysis would be a bit overkill, unless you were going to decide to market them and attach a receiver for towing, then you might need to do some structural analysis for towing strengths etc. As it is, I would say...weld away as you are building this thing to thrash it, so use the material that is easiest to work, cheapest, lightest and most readily available that will do the job...and don't forget the



Disclaimer: These opinions are mine and may or may not bear any resemblance to sanity!

P.S. I think I am going to keep my 2" RB BL as I don't have any issues with my insurance company like I thought I would! Sorry if this is an inconvenience and please accept my sincerest apology!

P.S.S. How ludicrously priced was your ADD to manual hub conversion for your 3rd genner and where did you get it?

Robinhood150

Oh you can definately get thinner, I built my bike rack out of 1/16" wall (or whatever the closest decimal equivolent is), 2inch square tubing.

SteveO

Well! Thanks for all the great responses, I do appreciate it. As you all know or may not know, I'm pretty hard on my rig when I'm wheeling (vids on my site). I like to take it slow and easy, but I certainly don’t shy away from the challenging lines, and sometimes things break. My previous rock skis were 2” x 4” x 3/16” rectangle tube. These units were very heavy, and my goal is to trim some weight off this 5000lb beast. Trying to make strong bumpers and rock skis light weight and strong is not an easy task.

The main section of my rear bumper will definitely be 2” x 4” x 3/16” for strength and rigidity, however the skirts and the rest of the parts will be much smaller and lighter.

The front bumper will have to have a large plate for the winch, and then from there I’ll go lightweight. I thought about hacking up my ARB bumper for better clearance and making it lighter in the weight category…….

Cebby

Tech Article

The Goods

zedex

I have a bumper Stevo that you might like. Its my original design thats sitting here collecting dust. It should bolt right up to your 99 runner. Its from a 98 taco. I would sell it for what i paid to build it. You can take a look at it here.

http://community.webshots.com/user/zedex1100

Its the bumper with the lights mounted on top of the bumper. black 98 taco.

waskillywabbit

iTrader: (-1)

Thanks Mike!

I won't be doing that anytime soon unless I have lost a whole bunch of change in the la-z-boy cushions... For that kind of moola I can just replace all the crap when it breaks!

Steve,

We just usually don't work with anything less than 3/16" in the fab shop is probably what it is and my AISC book doesn't list any thinner walls. ASME code work just doesn't allow wall thicknesses so thin on that diameter tubing.

Flygtenstein

Round would have less weight?

Steve beats his stuff, that is what he meant to say above.

My sliders are .120 wall tube and have gouges but no kinks with my 5k baby wallowing on them. I think that the round rather than square makes sense for sliders.

Front bumper should be framed in heavier, like 3/16", stuff. Anything not structural should be as thin as you can go.

I think that using square on the bumpers makes sense, but round on the sliders.

As you mentioned the rear beam should be thicker, but the front less so. I drop me rear and grind my front.

SteveO

Waskillywabbit, I'm sorry, not trying to ignore your question here.

I can't really say what the price was for the manual hubs install alone, as I had my ring gears front and back changed out, plus the ARB installed in the front (minus the ORS half shafts and ORS outboard joints). To say the least, it was a lot! :pat: There was quite a bit of labor in the price, and as expected it took longer than normal. With that said, the front clam shell (diff) is not leaking any oil, so that is a good thing. However, the rear diff did start to leak oil, and under closer inspection, the gasket was missing. In its place was gasket maker goo. During my rear spring swap, I found that the locking plates for the ring gear bolts were also missing. I placed a quick call to Mike at ORS about this and was told that some Toyota diffs do not even have these locking plates, however if my did come with them, they should have been put back in. Also, they used loctite on the ring gear bolts, and that I should not have to worry about it. He has never had an instance where not having the locking plates in place (with his work) has allowed the ring gear bolts to come loose. OH yeah, I checked the ring gear pattern...right on the mark. Who ever did the ring gear setup, did a really good job, the patten is right in the middle of the ring gear teeth. Nice setup.
As for the locking plates for the ring gear bolts.....the manual says they should be there, however I'm going on his experience, and I hope that he proves to be right on this one. Or my 3rd member may explode some day. Actually, I have ordered the plates from the dealership, and when they come in from back order, I'll get em on.

Anyhow, the front end has worked great. One thing that I found after I broke the ORS shaft is that too much downward flex can be a bad thing. I found that the ORS half shaft itself was rubbing on the inside of the inboard joint during downward flex. Of course this is not a good thing for the half-shaft, and over time, will continue to eat it away. Just and FYI. I'll have some pics of this broken shaft on my site fairly soon.

One thing I did notice after the kit went on, was how much lighter the steering wheel felt, and the rolling resistance of the vehicle seemd to feel a bit lighter. I'm sure with all the front diff parts not turing, this will make it easier for the 5klb beast to get down the road.

Would I do it again? Yes I would. Those boots take some abuse as they are rolling down the road, and with my not turning at all when I'm on the road, will allow the boots to last a bit longer. So many times, I see Toyota trucks running down the road with a torn boot flapping around the half-shaft. When an opportune moment presented itself, I have told the driver that they have a torn CV boot, and it not replaced will destory what is left of their CV joint, thus costing them more money.

Anyhow......again...IMHO, If you plan on keeping your IFS setup, I would recommend this route.

SteveO

Quite a bit too. I'm not like trying to beat it up, I just use it as it was designed to be used, protection.


I would go round, but in the interest of saving money (and making sure the wife agrees) I need to take the cheaper route and make it myself. Without a tube bender, round becomes a bit of and issue. Yes, a pipe bender could do, but sticking to square would be easier.


I'm starting to lean towards hacking my ARB unit up to gain more clearance on the approach angle. Zedex, how much would you want for your bumper, and how much does it weigh? Looking at the pics, I know I would start hacking that one up as well. I would have to cut the lower portions next to the tires to get a little better approach angle.



HUH???

BruceTS

'99 4Runner Limited, heavily modified


someone forgot the "i"........


I started work today fabricating my rear bumper, I'll post pictures as work progresses. I like Trailcarnages design, it's similar to what I originally had planned on doing. I since redesigned my bumper and added some features of his. The biggest difference will be in departure angle off the side pieces.

SteveO

yeah, I know, typing too fast and not really checking what I type, as usual.

SteveO

BruceTS, do you have a site where these pics will be, as well as your information?

BruceTS

I'm working on building a complete site, but I've been busy trying to get my 4Runner finished before the All Pro Jamboree, fortunately I'll have more time, since it was postponed. Hopefully next month when the rainy season starts, I'll be able to get it up. I guess I should just upload what I have completed and then add to it.

I do have a continuing post at another board with all that I have done so far. It's here: http://www.goldcoastcruisers.com/
their forum under Cruiser Talk/My project

and also have photo's posted at tundra solutions there's a link in my sig.

waskillywabbit

iTrader: (-1)