swing arm design doodle.

harpo57

harpo57

owner of basket case
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Well its Saturday night so I'd I thought I would drop by the lounge to discuss my swing arm mod. (feasibility study) Opinions and debate welcome. The premise of this mod is to create the illusion of hard tail while retaining suspension. (soft tail) the main attraction of drawing (not to scale.. lol) is the proposed swing arm. Starting at the pivot point on frame. Come down to equal height of front cradle frame. Extend rearward parallel with front frame. Then up to axle/shock mount. Swing arm is of length longer than stock swing arm. Properly built and gusseted/reinforced, should work? It should not change the swing arc? Thoughts? Hope it can be seen in pic. Yes, my sketch includes a couple of other frame mods... :)
 
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You're gonna need a gusset down where your arrow is... on that 90. Other than that it should work.
Would look better if you could find a way to hide the shocks...
 
harpo57 said:
Well its Saturday night so I'd I thought I would drop by the lounge to discuss my swing arm mod. (feasibility study) Opinions and debate welcome. The premise of this mod is to create the illusion of hard tail while retaining suspension. (soft tail) the main attraction of drawing (not to scale.. lol) is the proposed swing arm. Starting at the pivot point on frame. Come down to equal height of front cradle frame. Extend rearward parallel with front frame. Then up to axle/shock mount. Swing arm is of length longer than stock swing arm. Properly built and gusseted/reinforced, should work? It should not change the swing arc? Thoughts? Hope it can be seen in pic.
Click to expand...
Ooh, more concept drawings then... :)
 
Your most important component is resistance to twisting.
Lots of alternate swingarm threads in here, but nothing in the way of quantitative comparisons of twist strain. A simple fixture could be made to measure twist/deflection/force values, like a spring tester. You'd want your proposed swingarm to have no less than equal twist strain handling to a stock swingarm.

You can achieve that by using the triangulated design of the softtail swingarm...
 
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.. this would lower the rear.... but what affect to the front end.. rake....? Saw a nicely done mono shocked XS with a triangular swing arm with bell cranks at Slimy Crud.. should have taken pictures.
 
Harpo,
The design concept for your swingarm mod seems as sound as anything else. I like the idea of having the 'lines' of a rigid, but still retaining a rear suspension. And I like your sketch with the modified seat loop. I was planning something similar for "The BAsketcase", with a seat loop of my own, and the "Joe Wiseguy" underbraced (and stretched) swingarm. Keep us posted. R & D is fascinating! :thumbsup:
 
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