Suicide front suspension materials, strong enough??

Hey,
I am going to set up a "suicide" transverse spring set up out front of my 1930 model a and I was planning on putting a round front cross member. I am putting a 302 in the car, hoping to keep the weight down around 2500 lbs. I have available for free some pipe about 2 3/4" OD 3/16" wall, is this strong enough for the front x member or should I be looking into tubing (DOM, chromoly, etc).. perhaps even larger OD or thicker wall?

Thanks in advance!

Justin

 

2-3/4" OD x 3/16" wall should be plenty strong. After all, it's attaching to what, 1/8" thick frame material?

 

Justin,
Your pipe size is fine but if it is strong enough depends on what type of pipe it is. Is it water or gas pipe? Then it should be used for that. DOM is good as well as mechanical tubing. Chromolly is kind of overkill unless you have a chromolly chassis already.

I may even go as thin a wall as .125 on my uibing instead of .1875 (1/8 or 3/16) but either will work.

 

Plumbing products are for plumbing.

 

Spend a few more bucks and get the proper DOM tubing. So much depends on that front crossmember being right that you really don't want anything but the right parts up there. And yes, 3/16 is fine.

Don

 

DOM, get some: http://www.metalsdepot.com/products/hrsteel2.phtml?page=rndtube&LimAcc= &aident=

 

I bought some black pipe for a front end, it was close to a 1/4" thick and it was cheap for a big stick. You should go thick if you go pipe instead of tubing.

 

Ok this stuff I have is high quality seamless pipe, I believe it is used in high pressure gas line pipe. Being high quality high pressure pipe that should be sufficient strength eh?

DOM is just the way the tube is made right? Doesnt that just mean its seamless or something?

 

dom just means it is (drawn over mandrel) after the tube is made and welded that is why it does not have the welded seam

 

Gas and water pipe are made from low quality steel. In a twisting or bending situation it will break. In a suicide front end you out it in a twisting situation with every imperfection in the road. It is not structural pipe.

You have already convinced yourself that I is OK from the way you are talking but I am going to make a recommendation again, use mechnancal tubing and leave water and gas pipe for water and gas.

 

You need DOM. Structural tubing is far different than pipe. If you decide to use pipe on the front end.......it will literally be a "suicide" front end. metalsdepot.com is a great site. If you keep the lengths under 8' it is standard UPS shipping. They beat every price I found locally by over $100, on a $230 order!

 

This reply is from your friendly materials engineer.

Structural tubing means no surprises!

Why most all of the sanctioning Auto racing folks require it,

in place of plumbing pipe.

 

Hey I have heard that old bed rails make good suspension pieces.

 

And never having to say, your sorry!

 

If you get going fast enough before the catastrophic failure you'll never have to say your sorry ever again.

 

ist that why they call it a suicide front end?

Godspeed
MrC.

 

Yep pretty much.

 

Can you say "Scrub line?"

 

Man, we go through this once a week! DOM only! And by the way DOM is not just welded pipe drawn over a mandrel. It is a true seamless. A lenght of 2 5/8 DOM from Wintec is like $25. Is your life and the life of everyone around you worth it?

 

Sufficient for a trailer queen that never sees the street, I suppose.

 

Sorry, your wrong......

 

Ok so I asked the guy who has the pipe I can use, he said it is made using the DOM method, what is the difference between that DOM and the DOM suggested by everyone? Not being ignorant just curious, and my mind isnt made up yet.. the thing that annoys me about bringing up topics in forums such as this is when people start putting words in your mouth. I am trying to gather facts. Stop making assumptions and reprimanding people and they are much more likely to listen!

 

There is only one kind of dom. As shown above, it starts out as a welded tube which is then Drawn Over Mandrels to a exact size i.d-o.d. (plus or minus a couple of thousanths) which erases any sign of the weld seam (which is why some think it is seamless)

 

ASTM A-53 and A500 grad B, C are the most common types of pipe you will come across. Water pipe if you will. Both are graded for structural use. It sounds like it is 2 1/2" sch. 40. Clean the laquer and mill scale off the outside before you weld it in.

 

Thanks Rootie thats helpful!
On the MetalsDepot site you guys suggest the round steel DOM tube? Britnell = 80; Tensile = 80,000; Yield = 70,000;
Which is the most important property?

Thanks again,
Justin

 

Brinell is the hardness, tensile is the point at which it deforms in strech or compression, yield is the point at which it bends permanetly. If you really think your ever going to reach those limits, you wont have to worry about it. You'll just be a red spot in the road.

 

Haha yeah red spot is not something I strive to become
So what are the units for those numbers then?

 

Pounds

 

wow yeah no wonder I wouldnt make it if I hit those numbers!

 

To be more specific, pounds per sq. inch. Here's a little more info that may be of some interest: