built my own swingarm

[posplayr]

BTW, I'm a mechanical engineer so I know what I'm doing. My consultation bill will be coming in the mail.

Well now you have really gone and done it . Instead of folding on a 40 mph corner where it would have been relatively safe, now we are looking at a 60 mph highside

Full leathers with a racing hump advised .

Pos

[Agemax]

would be ok for a 1;12 scale model, but for a real bike?????? f*&k that

[posplayr]

A little help

can make you dangerous

http://www.thegsresources.com/_forum/showthread.php?p=997664#post997664

Pos

[Dave8338]

Mannn, all this talk of stiffness and elongation has me a little concerned as to the content of the thread.

POS you do have some genuine concerns but keep this in mind: the moment needs to be chased all the way around the structure. In this case (with the spring/shock combo located at or near the rear axle) there is more vertical surface area (add the trig and call it a day) than in a mono shock configuration. Were it a mono shock set up, I would be worried.

[posplayr]

Were it a mono shock set up, I would be worried.

Ironically, if it were monoshocked, he would have at least cross braced the swinger (for the lower shock mount) improving the stiffness by some 50%.

[Nessism]

can make you dangerous

http://www.thegsresources.com/_forum/showthread.php?p=997664#post997664

Pos

Interesting post coming from someone with an aluminum swingarm. Young's modulus for Al is 1/3 that of steel. It's not all about moment of intertia.

[posplayr]

Ed

Interesting post coming from someone with an aluminum swingarm. Young's modulus for Al is 1/3 that of steel. It's not all about moment of intertia.

Shame on me ; Here I go again, trying to "spoon feed" a technical discussion on a non technical website .

BTW, while you were copying the stock swingarm design to cross brace that steel swinger, did you stop to realize that despite the modulus advantage, the engineer still found it nessesary to add all that weight by adding the cross brace on steel swinger?

[Dave8338]

Shame on me ; Here I go again, trying to "spoon feed" a technical discussion on a non technical website .

I design structural retaining walls for a living 6 months out of the year...

[Agemax]

stuff the technical crap, you need one of these!



no flex on this arm!

[posplayr]

I design structural retaining walls for a living 6 months out of the year...

OK, I'm glad your are employed. What is your point?

[Nessism]

Shame on me ; Here I go again, trying to "spoon feed" a technical discussion on a non technical website .

BTW, while you were copying the stock swingarm design to cross brace that steel swinger, did you stop to realize that despite the modulus advantage, the engineer still found it nessesary to add all that weight by adding the cross brace on steel swinger?

Sorry but missing your point.

Found this link showing some aftermarket swingarms. Not a whole lot of bracing on these... http://www.redlinecycle.com/Swingarms%20-%20Hardy.html




BTW, check this link for some photos of a Kosman swingarm for a KZ1000 (not much bracing). http://www.redlinecycle.com/Kosman.html

And found this link showing some nice bracing ideas... http://www.fastlaneracecars.com/html/logos.htm

[Hammered]

Sorry but missing your point.

Found this link showing some aftermarket swingarms. Not a whole lot of bracing on these... http://www.redlinecycle.com/Swingarms%20-%20Hardy.html




BTW, check this link for some photos of a Kosman swingarm for a KZ1000 (not much bracing). http://www.redlinecycle.com/Kosman.html

And found this link showing some nice bracing ideas... http://www.fastlaneracecars.com/html/logos.htm

Your photo brings up a good point that some may be missing. The aftermarket Swingarm has one piece bent tubing. The one in question in this post is cut and stubbed to add to the length. Id like to know, did you add an internal slug tube to regain some of the structural strength lost to the cutting and welding. Its not as true as some may believe, a weld is not always the strongest point in a union of multiple pieces of metal. And the way and area the extension was added, also will increase the width. So did you iensure the extensions were welded back in straight?

You may want to research over and under bracing swingarms. It will answer some of the question you may find yourself asking later as the project goes on. I too would think about adding a cross brace at some point ahead of where the tire will still. This will take a great deal of pressuer off the axle and remove as such a pinch point. Id also be curious about the grade of steel you used. Thats far more important than how think the wall is.

[tkent02]

That cross brace six inches back probably makes the swingarm about four to six times as rigid against twisting as the same piece without the brace. Just a guess as I'm not a mechanical engineer.

[Nessism]

That cross brace six inches back probably makes the swingarm about four to six times as rigid against twisting as the same piece without the brace. Just a guess as I'm not a mechanical engineer.

My guess is about 25% more ridged.

[tkent02]

My guess is about 25% more ridged.

Wanna bet?