Re: Swingarm question anyone know?

Posted by shinyribs on Nov 04, 2013; 9:45pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Swingarm-question-anyone-know-tp4046740p4046751.html

Hmm...tough call between stretching the arm vs. moving it's mounting position.

I agree with Tools that new pivot mounts would be easier than stretching the arm, unless the arm is tubular and has parallel legs, which I'm not sure if yours does. But chain geometry would be my concern. When I first started on hackjob (remember that forgotten build....?) I was wanting to move the pivot location. As it turned out, that was gonna create a lot of issues. The placement of the swing arm pivot in relationship to the front sprocket is critical in order to keep chain tension somewhat consistent throughout its arc. When you alter that position stuff gets crazy fast. When I looked into stretching my.wheelbase 2" I mocked it up and checked for chain clearance. My concern at the time was the chain dragging frame tubes or the swinger itself. What I discovered was that my chain (while travelling thru the arc) would go from super tight to about to flop off. So I scrapped the idea and just went with the extra 2" the new arm was already giving me. A 2" longer (or any amount, actually) swing arm will disturb chain arc tension also, but the effects are extremely minimal compared to moving the pivot away from the front sprocket.

My $0.02, mock it up and see what's up. In the end physics may make the decision for you.