Frame Question

[Couper]

Thought I'd put this in the Frame section where it belongs. Couple frame questions. Most of the frames I see like Bruno's have a taper under the cab....wider in the back and narrower at the front of the cab and engine frame rails. The frame on my dakota and the motor home I looked at the frame rails appear to be parallel front to back with outriggers to pick up the cab mounts. Is there a reason why I couldn't build my frame that way? Also some frames I see are stacked 4" on top of 4" others are "Z"ed. Is the purpose of the "Z" to get the frame rails higher in the engine bay? And in the rear some "Z"d and others just a 90 degree kick up. Maybe stupid questions for you vets...but I'm trying to understand this better.
Thanks
Couper

 

[Old Iron]

You can build the frame anyway you choose, mostly just the builders choice.
The frame that is wider in the rear narrower in the front, is to get the rear springs farther out towards the wheels for stability, narrower in the front to clear the front tires when turned to full lock.
The frame I built for the Chopped Channeled and Narrowed truck is straight through. I did this to purposely keep the rails close in the rear for looks.
The stacked rails are to make the frame stiffer.
The factory done this frame Z process, the Z's are to make the vehicle body lower without using the suspension to do so.
This is just my take and others may have different reasons.

 

[Couper]

Old Iron.... Thank you for that. I'm going to hop around a bit. On the other thread ZZ recommended doing a chalk drawing of I suppose you'd call it a stack up.

Well I did a to scale colored drawing tonight showing my rocker cut out, where the cab frame would sit based on where the floor mounts will be along with a 4" tube stacked on top of the cab frame for the motor. I will include a picture.

I choose a 6" ride height on which I'd like to bag to drop when parked....it doesn't have to lay frame but 2" off the ground would be cool.

If the axle is going to mount under the frame (and I'm still not sure what gives with under the frame versus out front) and I need is it 4" of travel (is that right?) between the axle & the engine frame. Using a 28" Dia tire I come up with a drop axle of about 8".

That 4" of travel will give me the parked 4" of airbag drop.......

Maybe I need more of a dropped axle????? 10" ????

I question this because the axle Bruno used I think was only 4" drop.

Is this why you put the axle out in front of the frame????

Lot's of questions but I feel like I'm learning some things.

Orange is the cab frame, blue is the engine frame, green is my body. The bottom of the paper is the road. The long skinny paper at the tape measure simulates the tire 28" tire. The faint dot to the left of the tape measure represents 4" of travel

I'm sure this has given you a headache Thanks for reading

Couper

 

[Couper]

Bruno....if your here please confirm the drop on your axle
Thanks

 

[bruno]

Yes it is a 4inch drop.

 

[Couper]

Yes it is a 4inch drop.

Thanks

 

[Couper]

I think I may have found a solution....

I believe that will get my front end high enough as to give me the travel I and let me have a nice drop for parked. Since I want to bag it I can fab a brace like in the picture to run from frame rail to frame rail to hold 2 bags. He has a Z that looks to be maybe 5 or 6"? That Z will give me the travel but my drive shaft / trans tunnel will be high but I think thats normal for these. What do you think? I've attached some borrowed pictures

 

[Skip]

Solutions are Us. Good hunting. [clThat frame looks like about six up in front, and 12 up in the back. Lots of room for air bags. Now to build it. [

I will be using a "tall" front spring hanger on my next project, rather than kicked up frame rails in front. Its a look I like. There will be a kick up in the back, though. More that one way to get it done.

Have fun. Build safe.

 

[Couper]

Thanks Skip... I'm still reading and learning and trying to feel my way this. I'd like to not have to Z or stack the front but with a 4" frame height and a 6" ride height my oil pan will be scraping the road.

Every day that goes by I am understanding and learning more thanks to you guys and a couple guys on Killbillet.

I will get there!