Subframe fab

[Junkie]

and with the seat on

 

[Junkie]

seems strong enough

 

[Junkie]

ok, got stuff mounted reasonably and am gonna whore out one last set of pictures. should be it for a while

 

[Rob]

I'da mounted the seat lower...


...




Edit: Sub looks tweaked.

 

[Junkie]

tweaked in what way?

 

[Rob]

Looks like the big white guy - standing on the back - might have had something to do with it.

 

[Junkie]

I'm trying to figure out where it seems to be bent. If it bent under my weight, shit needs fixing...

 

[Rob]

Don't go nutz trying to figure it out... it maybe just the camera angle but look at the last picture. The rail doesn't look straight. Maybe you designed them that way, maybe they are straight, maybe I'm crazy, maybe it just doesn't matter. Either way I still give it a

 

[Junkie]

you're right, not perfectly straight. most likely I just didn't build it quite perfectly, if it gets worse I'll be concerned.

 

[DannoXYZ]

Don't go nutz trying to figure it out... it maybe just the camera angle but look at the last picture. The rail doesn't look straight. Maybe you designed them that way, maybe they are straight, maybe I'm crazy, maybe it just doesn't matter. Either way I still give it a

Yeah, the rear half is untriangulated cantilever. Really overloaded area as so many pieces are joined at one spot. Might have been better to move the attachment for the bottom truss back a couple of inches. Could also have been some misalignment that was overlooked when they welded.

 

[Junkie]

Rear half takes minimal loading. Most likely due to welding/fitment issues. Likely doing some gusseting anyway.

 

[Ironbutt]

Yeah, the rear half is untriangulated cantilever. Really overloaded area as so many pieces are joined at one spot. Might have been better to move the attachment for the bottom truss back a couple of inches. Could also have been some misalignment that was overlooked when they welded.

He fitted the steel, I welded it.

It's not crooked -turn your head the other way.

 

[Junkie]

it is actually a little bit crooked, on one side only. I'll be making some gusset plates at some point.

 

[MotoWhip101]

SO RAD!!!! This might be my favorite SV

Edit: Powdercoat rear wheel/swingarm black?

 

[Junkie]

I plan on having a spare swingarm braced, and it'll probably end up black as well.

Also, for gusseting, here's what I plan. Black is existing, blue is welds (some existing, some new), red is gusset.

That's what my father suggested... he's a structural engineer, but does bridges mostly - rather different subject than a subframe.

 

[Rob]

Fizziks is fizziks.

 

[Whisky_Richard]

I plan on having a spare swingarm braced, and it'll probably end up black as well.

Also, for gusseting, here's what I plan. Black is existing, blue is welds (some existing, some new), red is gusset.

That's what my father suggested... he's a structural engineer, but does bridges mostly - rather different subject than a subframe.

I would make the gusset a triangle instead of the V-shape you have drawn. You can still have it tie to both members on the right side. Also, if you want to stiffen up the back half of the subframe, just weld some strips of steel to the top and/or bottom of the tube. If you plan to reinforce the back half of the subframe, definately add a gusset as you will have a stress concentration at the joint you have drawn.

 

[Junkie]

the problem is that if I do a full triangle instead of what I show, it's not as strong unless the backside gets welded on, too... and it's rather difficult to get to.

 

[auntiebling]

the problem is that if I do a full triangle instead of what I show, it's not as strong unless the backside gets welded on, too... and it's rather difficult to get to.

weld in a filler plate to cover the V section, then add speed holes. it'll be way strong either way

 

[DannoXYZ]

Also, for gusseting, here's what I plan. Black is existing, blue is welds (some existing, some new), red is gusset.

That's what my father suggested... he's a structural engineer, but does bridges mostly - rather different subject than a subframe.

No need to get that complicated. You are doubling up wall-thickness suddenly in that area and will cause a stress-riser. Would be OK if you taper the reinforcement plate thinner at the ends, but that leaves little surface-area for the weld. Just add a gusset under the cantilever arm.

Something like 4mm thick plate on the centre of the tubing will be fine. If you really want strong, then 2x 3mm thick plate on the inside and outside edges will be more than enough. Take a look at how the head & down-tubes are braced on a BMX bike.