How heavy should the frame tubing be?

[gold03]

I know it has probably been asked, but here goes.

1949 flathead with a dana 44, 16 inch tires, suicide front axle. How much steel to build a back section? What size of tubing is actually needed? I tend to over build things. Adds weight and strength but also cost as well. This is no big power ride, just for cruising. 2x4 or 2x3? What thickness?

I look at some of the original C-channel car and truck frames that have been in service for decades and wonder about my tendency to overbuild.

Any thoughts?

 

[RPM]

I know it has probably been asked, but here goes.

1949 flathead with a dana 44, 16 inch tires, suicide front axle. How much steel to build a back section? What size of tubing is actually needed? I tend to over build things. Adds weight and strength but also cost as well. This is no big power ride, just for cruising. 2x4 or 2x3? What thickness?

I look at some of the original C-channel car and truck frames that have been in service for decades and wonder about my tendency to overbuild.

Any thoughts?

The dana 44, 16" tires,and the suicide front axle, don't play into the size of the frame. These items are unsprung weight and they support the frame. We build T Bucket frames from 2 x 3 3/16" wall tube. The model A rat frames we build from 2 x 4 1/8" wall or even a combination of the 2 tube sizes. Wheelbase will play into this as well. The longer the wheelbase the bigger the tube needs to be.

What are you going to be setting on this frame, body wise?

 

[mitchs66]

From what I've been reading on here 2x4 3/16 wall is used a lot[S

 

[donsrods]

We use 3/16 wall because it gives a little more thickness to tap threads for non structural items like line clamps and stuff like that.

Don

 

[gold03]

RPM,

Thanks for the input. Body will be a 1949 ford cab. Building a bobber. My intention is to get the rear wheels as close to the cab as suspension will allow, and the front will only go out just to clear the grill.

donsrods,

The 3/16 for threaded holes is a good idea.

I appreciate the feedback guys. I think for the first time frame builder it could be very tempting to go way overboard.

I'm still looking for a rear end, and need to find one before I determine the rear suspension set up so there are a few options in mind. I like the idea of leaf spring over frame for the back end. If I can do this and still have a safe scrub line, I might give it a go. Will take a tall tire though.

 

[justsomeguy]

Just a question, do you have enough welding experience to safely build a frame?

 

[gold03]

I think I can handle it

 

[goose-em]

RPM,

Thanks for the input. Body will be a 1949 ford cab. Building a bobber. My intention is to get the rear wheels as close to the cab as suspension will allow, and the front will only go out just to clear the grill.

Think in proportions, maybe what you suggest will look good, maybe not.

I see many bobbers that are short in the rear but just look wrong.

Think about the human body, legs = 2/3 of the total height. If you had really short legs and a long torso with no neck you would look pretty silly.

Sketch it out or photoshop a photo and ask your friends to have a look.

Sorry that was OT.

If you don't have welding experience have someone else do the welding or at the very least take a couple of classes and practice until you can make a decent weld.

 

[gold03]

I should clarify on the welding. New to rat rods does not necessarily mean new to fabrication. This is just a different direction for me. When I head in a new direction I will ask lots of questions to garner the experience of those who go before me. That would be some of you guys.

I have been involved in building off road vehicles that have been function before form, and my concern is turning out a project that is over built. Over built Rat Rods usually looks big and bulky. I am fighting my tendency to worry about how it will handle being jumped... rolled over several times... fall off a cliff... etc. To me the forged 1947 Ford car front axle I'm going to use looks very fragile and dainty. I originally planned to build with a Cummins and Allison auto on one ton axles. I am trying to scale it back.

"Think about the human body, legs = 2/3 of the total height. If you had really short legs and a long torso with no neck you would look pretty silly."

Good advice. These are the lines I am looking at. Thank you to the owner of this truck. It is an example of the style/proportion I want to end up with. There are many examples on here and other sites I could have used. I just happened to have this one on my desk top. I am possibly looking at taller tires though in the rear.

Thanks for the feed back and the cautions.

 

[IAM-LDS-2]

scrub line

Scrub line is something that is often overlooked or ignored in order to give a rat truck that low down look . It is the size of your rim that comes into play when determining your scrub line - not the OD of your tires . When your rim goes to the pavement ( no matter what the tire side wall size is ) after a blow out , nothing should be able too touch or scrub the pavement . a 16" front rim and a 18" rear rim will help give you a bit of a rake which always looks good and will help with your scrub line .

 

[gold03]

Tall rim, tall tire. That's what I'm looking for. I would like a Dana 44 out of a TJ Jeep. Lots of rim options in 16 inch. If I can find taller rims I will be going that direction. I understand scrub line and how it relates to the rim, frame, and tire.

I blew a tire one time on a Ford truck loaded with lumber. The rim actually broke off the centre section. Four lane hiway. That was quite the ride. It didn't go onto the frame, but just being on the centre section at 60 mph ruined some perfectly good underwear! Don't want to be on the frame rails, at least the rim responded a little to steering input.





I can't rem

 

[Old Iron]

"Over built Rat Rods usually looks big and bulky. I am fighting my tendency to worry about how it will handle being jumped... rolled over several times... fall off a cliff... etc."
Yep know exactly what you're fighting
I built asphalt latemodel chassis before my ratrod life and the safety of the driver, occupants, is paramount
OK, even the nuts in the rods need safety too [ddev
Since I've been a member of this terrific site, I've read, reread, made computer folders for the different steps of the builds I like the most. Now I have an understanding of the design of these rigs [S
Enjoy and get a build thread goin [P

Jim

 

[Old Iron]

Tall rim, tall tire. That's what I'm looking for. I would like a Dana 44 out of a TJ Jeep. Lots of rim options in 16 inch. If I can find taller rims I will be going that direction. I understand scrub line and how it relates to the rim, frame, and tire.

I blew a tire one time on a Ford truck loaded with lumber. The rim actually broke off the centre section. Four lane hiway. That was quite the ride. It didn't go onto the frame, but just being on the centre section at 60 mph ruined some perfectly good underwear! Don't want to be on the frame rails, at least the rim responded a little to steering input.




I can't rem

[ddev [S [

Jim