DTSFab.com (Desert, Trail and Sand)

UTV's Off Road ( RZR, YXZ, Mini Buggy, Carts,etc.) => UTV Chassis and Suspension => Topic started by: CrazyFastFab on April 21, 2012, 09:08:51 AM

Title: Crazy Fast Rear End
Post by: CrazyFastFab on April 21, 2012, 09:08:51 AM
Hello,

I have been pouring over the forum and come up with this design.  Yes, it auspicious looks just like DS's frame.  DS has been immensely helpful and gave me some dimensions.  I have ordered the front end from him so I figure that is taken care of.  I am a big fan of design review so I was hoping you guys could look over drawings.  I am hoping you guys can provide two points of criticism one safety and two constructablity.

Thanks in advance,
Title: Re: Crazy Fast Rear End
Post by: Yummi on April 21, 2012, 09:19:14 AM
Wanted to get some jpegs up for ease of use of others.   

About the only thing I would suggest is get rid of the red shocks.  Proven fact red shocks do not work as well as blue ones. 

The smart ones will chime in soon.  For now you are stuck with the smart ass one.
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on April 21, 2012, 09:38:07 AM
 The red ones look like they are welded to the A Arm, still working on the drawing.  Ya, but I already have the Sway Aways.
Title: Re: Crazy Fast Rear End
Post by: dsrace on April 21, 2012, 11:32:56 AM
sure is a nice looking chassis and design if I do say so myself!! ;D
Title: Re: Crazy Fast Rear End
Post by: dsrace on April 21, 2012, 11:34:38 AM
I do pre-fer blue shocks myself too which are now black btw!!   ;D
Title: Re: Crazy Fast Rear End
Post by: trans man on April 21, 2012, 12:15:45 PM
sure is a nice looking chassis and design if I do say so myself!! ;D
LMAO LMAO LMAO
Title: Re: Crazy Fast Rear End
Post by: Carlriddle on April 21, 2012, 01:47:46 PM
Black/blue thru. Looks long but could be angle?  Drag slicks?  What kinda power
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on April 21, 2012, 04:56:57 PM
The frame is 144" nose to tail.  I have a '08 Hayabusa and Jeffco to make it go.  I need to get rims, tires and axles to start the building.

There is a really good chance the rail is going to be red as well guess I am stuck in a rut.
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on April 21, 2012, 05:06:48 PM
What type of tubing are you guys using?  Yes I know DOM is the good stuff but the price here is one foot of DOM is the same as 20 ft tubing with a seam.  I guess I know the answer but was hoping not to spend that much on steel.
Title: Re: Crazy Fast Rear End
Post by: dsrace on April 21, 2012, 06:36:34 PM
if your going erw use 1026 ( this is what I bought a truck load of way back when ) grade if they have it there in .095 wall other wise if all they have is standard 1010 i would go  .125 wall. 
Title: Re: Crazy Fast Rear End
Post by: fabr on April 21, 2012, 11:11:25 PM
I'm going tp suggest using a true A arm on top with a single heim . Makes adjusting/aligning a whole lot easier and is plenty strong IMO.
Title: Re: Crazy Fast Rear End
Post by: Engineer on April 22, 2012, 02:11:56 PM
Looks good!  ;D


What drawing program are you using?

What is the wheelbase?

Is it going to be a 4 seater?  I ask because you have two cross bars in the drivers compartment.  The rear bar to the rear wheels seems adequate room for the motor and chain so I am not sure what is going between the two bars unless it is a very small back seat.

A straight side view would be very helpful.

The diagonals on your sides really should land in the corners not in the middle of tube spans.  So in the drivers compartment you leave the bar up to the A-pillar the same so that it is easier to get in, but the bar below the mid bar of the car I would angle back at the bottom so that it hits the corner of the bottom tube and the upright tube.  The angle change will be hidden if you put panels on it anyway.

Same goes for the rear diagonal.  It should meet where the lower frame rail bends up.   You want to make the diagonals into triangles with the main tubes.  If they form a four corned box then it can "parallelogram" the whole thing with each of the tubes flexing a little but when it is a triangle the tubes don't want to flex, they would have to stretch or compress and that is how they are strongest.

Also with A-arm suspension in the rear if you lay the shocks very far forward you will get a negative progressive action at the bottom of the stroke.  (the further the shocks compress the more they will lay down because the A-arm is traveling straight up.)  It might help to do the cad work on the stroke length of shocks you have vs the wheel travel you want to establish how high the top shock mounts will need to be, and how far out on the arms they will be attached.

Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on April 24, 2012, 11:19:37 PM
 Thanks  for the input.

That is out of BendTech took about two hours to complete the entire frame.  I started my career as a Drafter in AutoCAD and I wouldn't want to go back to it for frames anyway.  I still like it for the flat pieces.  I have the BendTech Sheet metal module but haven't played with it much.  Best best thing about Bend Tech is it gives you the bend instructions for the bender, really nice.

Good point on the tubes going to the corners I think I just got a little crazy drawing and stopped thinking.  The frame is 144" long.  I didn't post the dimensioned drawing out of respect for DS as it is really copy of his frame, when it is done I will send the base files to him.  I am travelling when I get back to the house at the end of the week I can post the a drawing that shows all three views.

It is a two seater it is just the angle you are seeing a cross member in the back side of the frame that looks like a second bar across the frame.  It is really nice to have 3D model to spin around on the screen.
Title: Re: Crazy Fast Rear End
Post by: Carlriddle on April 25, 2012, 06:48:54 AM
So you got the good CAD drawing from DS.  ;D  If I had gone with the standard 2 seater I'd just let him build me a frame.  Less headache and possible cheaper.  Shoot he not doing anything, yest he was running down batteries on the remote.  LMAO LMAO LMAO

Looking good BTW.
Title: Re: Crazy Fast Rear End
Post by: dsrace on April 25, 2012, 03:34:26 PM
carl!!!!  only after mowing till dark  and no he didn't get greasy finger prints covered prints like you did lol lol  just measurements ;D ;D   he had so much already just from looking at pics it seemed pointless to send them when all he needed was a couple key measurments and he bought a front end kit.

engineer draw some lines of what you are talking about.

crazy fab can't wait to see them
Title: Re: Crazy Fast Rear End
Post by: Engineer on April 26, 2012, 12:05:03 AM
Squiggly tubes.

(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fwww.dtsfab.com%2Findex%2Findex.php%3Faction%3Ddlattach%3Btopic%3D4319.0%3Battach%3D25772%3Bimage&hash=85999c84b60b2b41855cd11cbc32d4b888143c11)
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on April 26, 2012, 06:28:30 PM
Ya, I copied those from Enemies car.  Triangulation is always the way to go.  Attached are 3 views.  I tried to convert to bmp but they aren't very clean so I included the pdf.  I left a couple of dimensions on there, the wheel base is 127 right now.  I still need to do some work around the seats to fix the supports in that area.  Generally I plan to used 3/16 steel plate that connects the Jeffco to the Hayabusa.  I also plan to use the 3/16 steel plate across the rear to connect the rear aarms to the frame and Jeffco.  To get that worked out I need to get my axles, i figure this will cut the wheel base a little as well.  When is that next pay check?  Oh Well.

Thanks for the input.
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on June 11, 2012, 06:49:03 PM
Another question.  Why don't people connect the rear shocks to the upper A-arm?  Seems like it would protect the shock from rocks and debris hitting it.  I was also thinking I would have to support the upper arm which would make a cage around the axle if something where to go wrong.
Title: Re: Crazy Fast Rear End
Post by: Engineer on June 11, 2012, 10:40:51 PM
Another question.  Why don't people connect the rear shocks to the upper A-arm?  Seems like it would protect the shock from rocks and debris hitting it.  I was also thinking I would have to support the upper arm which would make a cage around the axle if something where to go wrong.

I would guess mostly because of how high that would put the top of the rear shock mount.  Actually I think that on the Barracuda the shock is attached to the top arm and the top of the shock is pretty high.

You really need to determine how long travel of shock that you are going to use which will determine how far out on the arm you would mount it.  Then you have to see if that is going to be inside or outside of the main tube running the perimeter of your frame and as the suspension travels how much it will swing in and out to clear the frame.  It gets kind of messy.
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on June 12, 2012, 10:42:49 PM
Here is a sketch of how I plan to mount the Jeffco and attach the Rear Aarms to the frame.  I will be cutting the blue parts out of 3/16" steel using a plasma CNC table.  Any thoughts? thanks.
Title: Re: Crazy Fast Rear End
Post by: Carlriddle on June 13, 2012, 05:26:31 AM
See the slots for adjustment, and I'm guessing a turnbuckle up top to ajust back and forth.  The two plates on the drawing above the Jeffco, ???
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on June 13, 2012, 09:45:32 PM
Ya, some type of turn buckle on top for adjustment.  The items above are what is going to connect the rear aarms to the frame.  I plane to have the frame go thru the 1.25" holes.  The long part fits in the knotch at the lower right under the Jeffco and will be boxed. in.
Title: Re: Crazy Fast Rear End
Post by: CrazyFastFab on January 20, 2013, 11:42:51 AM
Well after a lot of thought on it I think I am going back to the 6 link setup.  Are you guys using the aluminium steering links are are those steel?  Thanks,
Title: Re: Crazy Fast Rear End
Post by: fabr on January 20, 2013, 06:54:51 PM
I think DS has used alum but went to steel .
Title: Re: Crazy Fast Rear End
Post by: Engineer on January 20, 2013, 09:33:35 PM
I bought a bunch of tube adapters from Doug Heim and went steel.
Title: Re: Crazy Fast Rear End
Post by: Carlriddle on January 21, 2013, 05:47:57 AM
Forward links are steel, alum for side links.  But DS did do all steel on this ride, prob another 10lbs.  I'd say depends on cars weight, and use?
Title: Re: Crazy Fast Rear End
Post by: dsrace on January 21, 2013, 07:13:05 AM
all my inboards are t6061 aluminum and lateral rods (forwards) are steel.  I think the aluminum rods would work for light weight in the lateral position but make sure... no matter what.... when you mount the shock on the carrier......  you mount directly over the axle or 1" - 2" in front of. if you mount it behnind the axle you'll apply to much load to the lower lateral rod, well if your rail is heavy enough and your jumping it, when it collapses you will not be happy! lol

I tried the aluminum lateral rods on my v-6 rail because I used them on all the mini's in the past and dunebound 69 runs them on his v6 but I messed up and had to mount the shock behind the axle. that happened once and the laterals went steel and the shock was moved forward, problem solved.  that v-6 rail probably weighed 1800 lbs though where my current is probably 1100 lbs and that v-6 engine was 400 lbs alone plus the 110 lb transaxle coulped to it.
Title: Re: Crazy Fast Rear End
Post by: dsrace on January 21, 2013, 07:21:31 AM
Well after a lot of thought on it I think I am going back to the 6 link setup.  Are you guys using the aluminium steering links are are those steel?  Thanks,

with the a-arms setup you  could play with a sway bar idea but I just believe this would be to difficult with the multi link. why not mount the shocks directly in board instead of out on the side on a a-arm rear?
SimplePortal 2.3.7 © 2008-2024, SimplePortal