Making rear bumper design. Help me out with the math

Ok I am looking at building my own bumpers rather than just doing the sensible thing and buying them. (Lets call it a man-truck bonding experience). I'm starting with the rear as it seems like it will be somewhat easier than the front. My measurments came out to 63.5" across the back. Thats 54.5' in the tailgate alone and I compensated 4.5" on either side under the tails. I also measured down from the top of the stock bumper to the reciever. I want a cut out where my reciever comes out so I gave 12" from the top to below the hitch. That leaves about a inch or two below where the hitch will come out. Now to the tricky part. On the ends Im thinking that rather than going with a 90 degree straight down I would take that 4.5" compensated on each side and go at a angle. Something like this:
(sorry for the horrible paint graphics and these are nowhere near to scale)
Now what I need to know is the length of the Hypotenuse. I know the lenghth of the top 4.5" and the imaginary line on the inside is 12" so the formula is a2+b2=c2 correct? C2 being the angled side. I got 12.816" but I was never the best at geometry. Am I going about this design all wrong or what? Does it have potential?

 

The Hypotenuse calculation is correct...Pythagorean Theorem is the way to get the legth of that side...I also got 12.816" as well...good luck...let us know how the design works out.

 

maybe i've been outside too long in the sun, but am i reading correctly that from the top of the bumper to the bottom will be an entire foot?

 

If I was going the size of the stock itd be around 7". But since I want the reciever hitch to come thru the bumper it is a foot. Its aprox. 11" from the top of the stock to the bottom of the hitch and I added another inch to it. I may not go 12" down on the entire bumper. I may drop it down from around 9.5 inch to the 12" in the middle.

 

or if you plan on doing any major offroading you can make your own hitch to so its not so low and your not dragging it across rocks

 

I wish there was rocks here . Im in the flat ass cotton belt. The majority of the offroading I'll be doing will be mud and light trails. This bumper isnt for major armour. I just cant stand the obnoxious chrome piece hanging from the ass end.

 

I would strongly suggest rethinking your dimensions, as 12" in either direction is just way too large. Maybe I'm just misunderstanding your description though.

Go download Google SketchUp. Its pretty simple to use and it has a free 30 day trial and will hopefully allow you to get down on screen what you intend to do.

If you want a simple, yet functional rear bumper, I'd suggest you look at

 

Ok I am rethinking my design. I am going to go down 8" and not cut out a spot for my hitch. To keep ground clearance. I'll try to get something rendered up and post

 

Ok here is a simple rendering done on google sketchup. (thanks maalaan)



I shortened it up from 12" down to 8" down and the hitch will stay where it is if I decide not to mod it and move it up. the kick ups on the side will go right to the bottom of the tail lights. Opinions

 

There are easy ways to cover chome

 

True but how many people have something on their truck that they can say "Hey, I designed and built this all by myself"

 

good point, and a shop would be in the $500-$700 range depending what you do most likely

here is what i did with my chrome

 

From the looks of it, you're trying to make it look kinda like a 2nd gen tacoma's bumper. So, does that mean you're going to be cutting out the metal under the tail lights, or trying to go around it? Also, are you planning on adding side protection as well, or just the bumper itself?

Maybe if you could make it 3d so we can have a better idea about the angles and such from different directions.

If you're planning to cut out the metal under the tail light, I think that might work ok (specially if you're adding in side protection), but otherwise, I think I'd stick with no kickups as it just doesn't work on a 1st gen very well.

 

Yeah I wasnt planning on cutting any sheetmetal. I thought the kick ups would be cool but defintely arent a neccessity

 

Here is one of the cleanest looking rear bumper designs ever made for a 1st gen. Maybe it'll provide some inspiration.

 

http://www.parksoffroad.com/tacomamods/bentuprearbumper/bentuprearbumper.htm

 

Heres how i built mine. Just a few Pics




I did cut the sheet metal on mine to bring up the sides for the side rails.

 

That is correct

btw - don't pull a Spinal Tap with some sort of bizzaro-Stonehenge

 

Ok I got around to re doing measurements and 3d rendering (silly work taking away from my tacoma time )

It is no longer so far down. It is now designed at going down 7" from top to bottom.


the top view

The box looking things on either side are actually raised 3" from the main. I may or may not include those on the final design.

Here is the a view where you can kinda see it all