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Discussion Starter · #1 ·
I had a shop make me up some struts for the back of my KZ750. They made them from 1-1/2" by 3/4" mild steel bar. I noticed after I picked them up that the bottom (swingarm) hole is sort of near the end of the bar, with about 3/16" steel at the end, like in the attachment.

I know that is more steel then is in most shock eyelets, but is that going to be strong enough? All that area has to do is lift up the wheel/swingarm if the frame gets higher off the road in a bounce, maybe 50lbs total on each bar. I think it will be fine. Anyone disagree?
 

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BACK ON TWO WHEELS
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for a proper accurate analysis, need to know how thick the bar stock is...if its 1/32" or .030 I would say too thin, if its 1/4" or .250" then prob yes...

so to make a proper analyzation, need to know material type, thickness and hole diameter...BTW i do this on aircraft every day
 

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They made them from 1-1/2" by 3/4" mild steel bar.
And the hole is roughly 10-11 mm diameter if I recall correctly (The size of the lower shock bolt).

Seems thick enough to me. And overkill on the strut.
 

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And the hole is roughly 10-11 mm diameter if I recall correctly (The size of the lower shock bolt).

Seems thick enough to me. And overkill on the strut.
I cant assess loading with out a thickness
 

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Discussion Starter · #5 ·
Not sure what thickness you are asking about. As I mentioned, the bars are 1-1/2" wide by 3/4" thick, 11-1/2" long, and the holes are 10" center to center. The hole is about 3/8" and the thickness of the steel under the hole is 3/16" as shown in the pic. The bars are made from mild steel (that's what I asked for but I'm not sure of the alloy). What else can I tell you? Steell, yea, they are overkill, but they actually weigh slightly less then the shocks did. Here's a rough drawing....
 

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GHOSTRIDER
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Not sure what thickness you are asking about. As I mentioned, the bars are 1-1/2" wide by 3/4" thick, 11-1/2" long, and the holes are 10" center to center. The hole is about 3/8" and the thickness of the steel under the hole is 3/16" as shown in the pic. The bars are made from mild steel (that's what I asked for but I'm not sure of the alloy). What else can I tell you? Steell, yea, they are overkill, but they actually weigh slightly less then the shocks did. Here's a rough drawing....
If a 10" cc hole layout on an 11-1/2" bar, there should have been 3/4" from the end of the bar to the center of either hole, that drawing will work but Im not understanding why theres only 3/16" wall thickness? Those holes should center up and leave at least 3/8" wall thickness drilling two 3/4" diameter holes. What size holes did they drill? If its not too late, fix it, if it is, keep an eye on the condition of the steel (signs of deforming) at the 3/16" end! Its a good idea and mild steel is plenty strong enough. Rounding off the ends and painting them the same color as the frame will look cool!
 

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Not sure what thickness you are asking about. As I mentioned, the bars are 1-1/2" wide by 3/4" thick, 11-1/2" long, and the holes are 10" center to center. The hole is about 3/8" and the thickness of the steel under the hole is 3/16" as shown in the pic.
Yep, like Zoro noticed those numbers don't add up.

11 1/2" overall length.
3/8" holes, 10" center to center.

1/2 of 3/8" is 3/16", so 10" center to center plus 3/16" plus 3/16" (two holes) equals 10 3/8", 11 1/2" minus 10 3/8" equals 1 1/8". 1 1/8" divided by two equals 9/16".


Edit:

I see by your drawing that the top hole is 9/16" instead of 3/8".
And your first post leads me to believe that the holes are not centered.
If you paid to have these made, I'd take them back and tell the shop to make them right.

If you didn't pay to have them made, then there is very little stress on the bottom of the hole, so I'd just install them and keep an eye on them. Course I would never install struts on a bike anyway, I wince just thinking about it :)

.
 
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