Subframe Piping or Tubing Types and Sizes Discussion

[Ray]

I want to create a subframe for my "Sting" project. The subframe will run the length of the frame about the width of the motorcycle out the back of the frame to support the GL1200 from underneath. My question is related to the "Tubing" or "Pipe" used to make said subframe. I went to the local hardware store and found that there are several types of pipe and tubing. The tubing used for conduit, pipe used for steam or water, galvanized, painted, threaded, etc. etc. All I read online is confusing and the terms are interchanged "tubes" and "pipes" when it comes to framing. I can't figure out what all this means. I feel pretty ignorant when it comes to this area and I need some guidance. It seems to me that the "pipes" are thicker walled and "rigid." I take it that it would be harder to bend but stronger. Galvanized would be hard/impossible to weld so no to that. I saw a post that seemed to indicate that I wanted "tubing" that is used for exhaust systems in automobiles.

Any education in this area would be greatly appreciated.  

[Ray]

I'm also struggling with the placement of my VW front end. The front is so light that the ball action is not compressed at all. I've been told to install adjusters to lower the front end. I'll look into that but I put tires on the frame, strapped it to the front. stood on it and it barely leveled out. If I move the axle back towards the cockpit, I have to modify the frame to accommodate the tires' turning radius. If I move it farther forward, I extend the wheel base. I read somewhere that the frame should be a perfect triangle. If that were the case, the vehicle length would need to be 5' long not 10' since the wheel base of the VW front end is 5' wide. I was trying to keep it about the size of a VW bug or smaller but the donor motorcycle makes it longer by its very nature. I'm not opposed to cutting the frame up some to change its dimensions but could use some ideas. Thanks.

[mtntech]

Tubing is measured by its OD and wall thickness. Pipe is measured by its ID because it is typically used for delivering something, such as fluids or gases. Find a metal supply and pickup some tube. I would use 1.5" There are basically 4 types. Seamless, DOM, CREW, and HREW. HREW is the most economical and fine to use. As for wall thickness, at least .090". Hope this helps.

[Ray]

This is very helpful. Thanks. I think the HREW part was missing in my research. Some people were referring to pipe and that was confusing me too.

[clintb]

Find a steel supplier, they will probably sell as little as you need, and will usually cut the 20' pcs in half for you.

 On the length, set in the seat and find where you want the pedals, then put the front axle just past the pedals. You will probably need to cut the front off.

Are you using square or round tubing? Don't worry about the weight, when you get the engine and swing arm mounted you will have enough weight to make it bounce up and down.

[clintb]

You need front end clamps, weld frame to and clamp on axle, you'll need 8.
www.dansperformanceparts.com/buggy/nuts/buggynuts2.htm

[stretchmobileski]

You could try Guntert Steel at 222 E. 4th Street. They should be able to handle your steel orders. I have an account with Patton's Steel in my area. Steel comes in many sizes and shapes. I also usually use .090 wall 1 1/2" tubing. My bender has dies for 1", 1 1/2" and 1 3/4" round tubing Exhaust tubing is very thin wall. I am actually only running the bottom leaves in my VW front end. You could pull the top leaves out and run a piece of all thread in it to keep the arms in place. Knock out the plug in the end of the trailing arms and put a washer and nut on each side. You are going to have to do some research on VW front ends. I grew up with VW's, my friends owned a VW repair shop and I have owned personally around 20 VW's. I am very familiar with them.

[Ray]

I bought the basic frame for $100. It is made with square 1x1. The front end was poorly designed for a homemade "A" type suspension. I have a VW front end from a previous project so wanted to use it. I have to modify the frame to make it work. I've been thinking about moving the seats forward that would bring the engine into the current frame and will shorten the wheel base. I don't have a lot of experience with VW. I did a Ghia restore last year but didn't change anything. The idea of pulling the top leaf sounds interesting. I will look into that. I have started researching places I can but steel tube. Thanks for the lead in Ripon. My budget is strict so shipping costs are a consideration. I want to redesign the top roll bar so will probably mix in some round tube. I also want to create a tube subframe to support the drivetrain. The brackets are a great idea. I will need to figure out where to attach them to the frame.

[DaveJ98092]

Hi Ray. You have a good start and with some mods it should be a nice trike. I have to think that that whole frame made from 1 inch square tubing that it would be a flexing nightmare with much more than a small motorcycle engine. I would add some 1 1/2 inch tubing to the bottom to help with flex. What was the power for that buggy before?

[Ray]

Feb 23, 2014 2:41:08 GMT -5 DaveJ98092 said:

Hi Ray. You have a good start and with some mods it should be a nice trike. I have to think that that whole frame made from 1 inch square tubing that it would be a flexing nightmare with much more than a small motorcycle engine. I would add some 1 1/2 inch tubing to the bottom to help with flex. What was the power for that buggy before?

Great question. I think it was supposed to be a VW engine but from the look and shape of the cage, it looks like it never was finished. I have been concerned about the structure and wonder about the strength. This is why I started this thread. I have been wrestling with ideas since I bought the cage. Yesterday, I put one of my engine-less frames with rear suspension in the mix to get a better visual. I moved it farther into the frame to reduce the overall length. This means some major changes. I will need to remove the front and reengineer it, then the rear needs to be redesigned, and the angles will need to be changed, and finally the top and passenger area. It is almost a complete rebuild. The only real advantage so far has been a 3D template to work from. As I replace and add changes, I want to use better materials but it leaves the weak links if I am not careful. Adding the 1-1/2 tubing substructure can give me a solid frame to attach my front beam and power train to. Sometimes i visualize this frame on a VW pan but I don't think it will help me much.

[stretchmobileski]

That's OK Ray. If you look at my build, I started with a reverse trike I got for free. I have used very little of the original trike. It basically was the inspiration to build the one I am working on now.

[Ray]

I think I may have found a supplier for my tubing. I'll have to check it out soon.