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MX Swing arm idea?

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Hey I was just thinking, what do you think the problems would be involved in making a swing-arm able to travel from left to right. Would the advantages be worth it?

So I was thinking of having the pivot point on a bearing of sorts with heavy loaded springs on either side, and the whole thing mounted on a heavy duty bracket that attaches under the rear shock(but can swivel left and right within the bracket as the bracket stays rigid in order to use the rear shock)

Would this mess with the chain mechanics? We're talking maybe 2 or 3 inches of travel either direction, anything else you might bring up?

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What is the purpose?

You'll never keep the chain on the sprockets if the swingarm moves sideways.

The handling would be downright dangerous. Why do you think cars with four-wheel-steering only move the rear wheels a couple of degrees?

If your chain will flex three inches to the side it's worn out.

Edited by Chokey

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What is the purpose?

You'll never keep the chain on the sprockets if the swingarm moves sideways.

The handling would be downright dangerous. Why do you think cars with four-wheel-steering only move the rear wheels a couple of degrees?

If your chain will flex three inches to the side it's worn out.

Hm I don't know I was thinking for a smoother ride on trails, through really rocky terrain, not neccessarily a mx bike but like a trail mx.

What if you could somehow attach the front sprocket to the swiveling mechanism?

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Allowing the front sprocket to pivot for chain alignment would require it to be mounted to the output shaft with some sort of ball joint. And you would have side-to-side chain clearance issues with the frame and engine as the swingarm moved from side to side.

How would you damp the sideways motions? A shock can only produce damping force when the shaft moves in and out.

I can only imagine how confused the chassis dynamics would be. What if you're on the gas as the swingarm is moving from side to side? The engine power would cause the rear end to pitch from side to side, and would probably be even more difficult to control than headshake.

I understand the principle of "sideways suspension", the factories spend millions in stress and load analysis to design some lateral flex into chassis for this purpose. But what you're proposing would be complex and heavy, with little benefit.

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I think that is one of the reasons the old XR's are so great, there is enough chassis flex to really make them shine.

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Isn't sideway movement what you don't want? What exactly does this movement do, in a positive sense?

Suspension can only absorb bumps in the vertical plane. When leaned over in a turn, bumps can't be absorbed properly and upset the chassis. Road race and sport bikes have a small amount of lateral flex built into the chassis to help with this issue, but sideways suspension is nothing more than a pipe dream.

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Actually why I brought this up. I was dreaming last night and this is what my yamaha had hahaha

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this is why dirt bikes use spokes. you never see a dirtbike with solid wheels like a street ride. the spoke flex and absorb some impact. the tires also help a bunch. im sure the swing arm twists a bit to absorb some bumps. adding an x axis shock absorber would not do much, plus 3" is wayyyyy to much for any chain to be able to work with. even if a chain was able to easily flex over to the side, it will quickly be pilled in a straight line by the engine power and do a ton of damage. also, when the "suspension" swings to the right, your chain would have to become longer to reach the sprockets and maintain proper tension would be real hard.

if you really wanted to try it out, you owuld need a special gearbox and driveshaft setup similar to the bmw motorcycles, just to get power to the wheel.

now what you could do, is add some rubber bushings just like automobiles have, to absorb impacts. it would probably work, at the expense of some handling. it would make for a smooth ride tho lol.

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