Suspension design 102

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tfaith08
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Suspension design 102

Postby tfaith08 » Thu Mar 12, 2015 12:38 am

Leaving off from the previous topic, you may have tried the car that I halfway built. If so, you may have noticed that the car is pretty hard to handle with a fully upgraded engine. The solution to that is to either move the engine to the front or extend the wheelbase (which I'll focus on).

Extending the wheelbase is simple, so long as you extend the other shock mounting position along with the swingarm. If you don't, your car will be very easy to bottom out (bad), but will ride a little rough as you go over small bumps (think beach or desert).

Taking the same car as before, I extended the wheelbase via extending the swing-arms and upper shock mount locations, as well as a few chassis mods to support them.

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If you plan to maximize the arm lengths, you'll have to make additional modifications to the car since the frame rails will only extend so far. Once you've done this, the ground clearance will get worse and worse in relation to the wheelbase. I got stuck on top of a hill on desert at around 2800m and couldn't rock the car off of it to finish the race. Luckily, the ATV industry has a solution to this: gull-wing arms. These allow the same suspension travel AND more ground clearance. They are simply arms that curve downward instead of making a straight shot from the pivot point to the wheel.

This is a gull-wing style arm on the same car above:

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The process for this is to build the suspension the exact same way as before, ONLY THEN should you add the gull-wing arms. I simply made a triangle out of 2 bars with an angle lock in the middle. I then removed the original arms and left the wheels at the same locations. This provides the same distance from the pivot point on the chassis to the wheel and the same distance from the pivot point to the upper shock location (which is exactly what you want), AND it increases ground clearance.

HOWEVER, you may notice that on extremely hard landings that the chassis may now buckle with no more additions than the straight arm to gull-wing modification. This is my solution to that:

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I generally perform this modification to both front and rear. This gives the correct geometry and allows about 80% of the increase of ground clearance to remain. I've never had this design flex or buckle.

The next set will be Suspension design 103. I'll cover a more dynamic front end which really soaks up the bumps and has tremendous travel, yet is very stable and controllable.
OP was drunk. All is forgiven.

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danieldorais
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Re: Suspension design 102

Postby danieldorais » Wed Mar 18, 2015 6:06 am

Great guides, thanks for posting!
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