Frame stretching

[ML-TOYS]

When you guys extend or stretch a frame what way do you do it ?
I was going to put a pipe inside the fron & back halves and weld, but then its a narrower pipe.....hmmmmmm

 

[KartFab]

This is how I would do it (never done it).
1) Put a pipe inside the frame after you cut
2) Get a same outer diameter pipe as original frame.
3) put same diameter pipe over smaller diameter pipe in the lengthened space. Leaving a small place to weld on each end.
4)put a large diameter pipe over it all on each end
5) weld small to regular
6) slide large over regular, weld large to regular
7) end result, 3 pipes thick. Large, regular, small.

 

[XtremeAaron]

I might be doing this as well to one of my karts.

Sent from my Razr Maxx.

 

[firemanjim]

Well, if it where meI've done this before), I would find a piece of SOLID bar with an O.D. the same size as I.D. of kart frame tube. And another piece of tube the same size as kart tube. Lets say we are gonna do a 12" stretch..... cut frame at location on stretch. You're gonna need 2 pieces of solid bar at least 4" long ,no more than 6"... and a 12" length of spare tube. Mark center of solid bar and grind a groove all the way around ,about .06" deep and 1/8" wide. Drill a 1/4" hole all the way through the tube about 1/2" from the end of bar. Jam bar into tube till center. Spot weld tube to bar through the 2 holes. Weld all around at the center. Repeat for othe side and your other "scab" tube. Drill the same type hole in your frame tubes. Assemble all the pieces together and tac, then check for square n plum...... if all is good, weld it up. When done right, no one will know you even did it. The method described in earlier post will leave a big bulge of un sightly pipe....... you cant hide.
Just so you know, this is the basic method we (vw guys) widen or shorten a frontsuspension beam in a sandrail or buggy. Its done this way all over the world... its proven safe and effective. ....

 

[chris_the_poser]

I have made several pieces for my buddies sprint cars at work the way Jim described it so it works in race cars to.

 

[landuse]

When cutting a kart in half, make sure to stagger the cuts on either side. You do not want to make the cuts in the same place on either side. This creates a weak point

 

[ML-TOYS]

Thanks Jim, that sounds like a perfect setup.
I will do the stagger Landuse, but how much ? Like 4 or 6 inches good

 

[DeathStarr89]

Here is how i did mine: http://www.diygokarts.com/vb/showthread.php?t=20551

I've beat the snot out of it and it's still holding up fine.

 

[landuse]

12 inches should be ok

 

[jandj]

Agree 100% with staggering your cuts. Also if you use a slug inside the tube to line things up don't use one any longer than you have to - a long slug will add rigidity where it wasn't designed to be (in a straight rail kart the frame is your suspension, you want a certain amount of flex).

 

[firemanjim]

Agree 100% with staggering your cuts. Also if you use a slug inside the tube to line things up don't use one any longer than you have to - a long slug will add rigidity where it wasn't designed to be (in a straight rail kart the frame is your suspension, you want a certain amount of flex).

I was re thinking my earlier post. On a kart, a 3" slug would be sufficient I believe. (1&1/2" per side of cut) I think any longer, will take the "spring" out of the frame....

 

[DeathStarr89]

IIRC my slugs were about 6", 3" in each side. That gave plenty of space between the rosette welds and the regular welds.

Any more than that is overkill IMO.


ML-TOYS, what kind of kart frame is it?

 

[ML-TOYS]

This kart that i did for my neighbor that i ended up with after he needed money. Of course now its all painted and complete but i need more room, not comfortable with steering wheel so close.

 

[firemanjim]

That thing needs a good atv/dirt bike engine..... I like the tire sizes....

 

[gear monkey]

If your back moter mount suspension take apart the back from the front and weld square piping fitted to the tubing then take the part where the suspension hooks up to that bar and extend that.
If you where to put slugs in the bars of your fame the welding would have to much stress on the frame and break I Know this from when I extended mine, I will try to post pics of mine

 

[ML-TOYS]

If your back moter mount suspension take apart the back from the front and weld square piping fitted to the tubing then take the part where the suspension hooks up to that bar and extend that.
If you where to put slugs in the bars of your fame the welding would have to much stress on the frame and break I Know this from when I extended mine, I will try to post pics of mine

If i do this it does nothing for what i am in need of. The main idea is for more leg room and steering further away from me.

 

[Doc Sprocket]

Have you considered just extending the front porch like I did? It's pretty easy do do, less worry about structure, put some more weight over the front wheels, and doesn't mess with steering geometry or turning radius.

 

[jandj]

Have you considered just extending the front porch like I did? It's pretty easy do do, less worry about structure, put some more weight over the front wheels, and doesn't mess with steering geometry or turning radius.

Doc is spot on. If all you need is a bit more legroom a porch is the easiest way to go. Bend you up a bumper, put a floor under it and relocate your pedals.....done and done.

 

[ML-TOYS]

i guess it should be raised a bit or my legs will be on the steering

 

[jandj]

You could use a couple aluminum (or make 'em from tin) blocks like the racers do to raise your feet.