Sheet metal formed trailing arms - WHAT THICKNESS

[standfast]

damn richard! where are You getting those material prices? my whole car is 4130 and i only spent about $2k for all the tubing and plate.

You need to look at the sheet 4130 available at aircraft spruce. thats what i used. if i were to do it over again i would have spruce send it to GK machine in oregon to be lasered. much better results than Waterjet and that place is wicked cheap. they can brake the sheet precisely for You as well. or there is a couple guys on race dezert that can knock it out for You as well that probably have the material in stock. i think there is a guy named craighall on there that deals with this stuff a lot. You can get a much better deal. let me know if You need any help.

[bdkw1]

Originally Posted by K-fab

Boy tell me about it. I was just quoted $1,600 in materials for my trailing arms. .085 for the main structure and .125 for the two internal ribs that the shock will attach to. From what the water jet guy said, they don't make 4140 in sheet form (as in a gauge size) and they were going to have to start out with .250 plate and grind it down to thickness. WTF???

My local guy has all those thickness in stock. I can get them cut out and shipped to you for less than half that.

.250 plate ground down LOL, where did you find this guy? it's 4130 sheet.......

[jersdunz]

DO YOU have your own cut file?? if so email it to clint@idahosteel.com
spec to him what you need and he'll get you a quote.. never hurts to try others..prolly wouldn't hurt to spec the zip code as well for shipping info

Originally Posted by K-fab

Boy tell me about it. I was just quoted $1,600 in materials for my trailing arms. .085 for the main structure and .125 for the two internal ribs that the shock will attach to. From what the water jet guy said, they don't make 4140 in sheet form (as in a gauge size) and they were going to have to start out with .250 plate and grind it down to thickness. WTF???

I spent the better part of a week designing and redesigning my trailing arms just to find out they'll end up being prohibitively expensive.

Needless to say I said F that. I may consider doing my arms in 1018, but I'm so totally pissed with my 10Dez (everything has been a compromise) that I'm ready to take it and throw the damn thing in the dumpster. Someone hands me $35K, comes and gets it and they can have the f'n thing.

I'll be redesigning trailing arms and be using 1.25" tubing now. Why not, it's all been a compromise and a constant kick in the balls.

[MC@ Performance Fab]

As light as your car looks you dont want heavy arms, unsprung weight versus sprung weight is a big issue.

[jersdunz]

Thank you all for giving me your opinions I really do appreciate it.

Originally Posted by MC@ Performance Fab

As light as your car looks you dont want heavy arms, unsprung weight versus sprung weight is a big issue.

I wanted to move to trailing arms because the 18 rod ends included in the
setup that i have is really expensive to maintain and half of them already have some slop and need replaced.

Originally Posted by MC@ Performance Fab

Having the bend close to the hub is prefered and having the pivots parallel to the hub is not.

Why is parallel bad? I haven't ever heard this before.. yes I am a noob

Originally Posted by standfast

Needs internal support to keep it from oil canning and as bracing at the shock mounts. .100 is sufficient if braced well internally. Doesn't look like you have any camber gain though. Try to set up your welds so they are inside corner and not outside corner by running the top and bottom pieces long. You should have a way to adjust toe as well. Heims...

Camber, I have read you guys talking about it, How much does it really help? I think I seen that tom pro uses 8d on his. (my stance is so wide and the sand is so close here I doubt I'll ever run it on hard surfaces. My plan was to have the parts tig welded corner to corner is that something that would cause me grief?

Originally Posted by bdkw1

I would also suggest wrapping the outer bushing/hiem housing. They have a nasty habit of ripping out.

The bottoms will see the most abuse and should be thicker, like 8 gauge. 12 gauge is fine for the sides and top. Internal ribs can be 14 gauge. And yes, you need them.

ok wrapping them wouldn't be too bad, unless I switch it to hiems. Any opinions on 5/8 being big enough hiem?

My car scaled at 720 lbs before I powdered it, but I have some heavier parts to it. I'm guessing in the realm of 760ish, Also I am pretty sure that sometime in the next two years I'll turbo it. Nothing super nuts though maybe cap it at 5-8 lbs. I'm going to make a few revisions to the design and repost later. thanks again

[bdkw1]

5/8's is plenty big enough. The pivots not being parallel to the hub gives it camber gain through the travel. Static camber at ride height should be 1-2* Pivots, 6* is a good place to start. you want about 3-4* gain through the travel.

[Bullnerd]

I had this pic on my computer,maybe it will help.For the angle ,that is.

[jersdunz]

Originally Posted by bdkw1

5/8's is plenty big enough. The pivots not being parallel to the hub gives it camber gain through the travel. Static camber at ride height should be 1-2* Pivots, 6* is a good place to start. you want about 3-4* gain through the travel.

Alright I have been trying to figure the best way to install this on a chassis that wasn't made for it so this is good to know during the process.
I wish I had more than 2d cad drawings done of my frame..

Originally Posted by Bullnerd

I had this pic on my computer,maybe it will help.For the angle ,that is.

Very much appreciated...

[yoshi]

Just got the top and bottom 10 gauge plates back. I measured the sides for the 12 gauge filler pieces and sent the drawings back to the plasma cutter. After I get the sides, and set them in 3/16" or so from the edge, i'll measure for all the internal bracing, then I have a special set of bungs with pinch bolts I designed that i'll have my machinist make....

[jersdunz]

Originally Posted by yoshi

Just got the top and bottom 10 gauge plates back. I measured the sides for the 12 gauge filler pieces and sent the drawings back to the plasma cutter. After I get the sides, and set them in 3/16" or so from the edge, i'll measure for all the internal bracing, then I have a special set of bungs with pinch bolts I designed that i'll have my machinist make....

Yoshi while I'm thinking about it, What are the bolt circle dimensions i would need to use that would let your outers bolt in when my Subaru stuff gives out on me? bc dia?, hole size? how many holes?