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Old 07-09-2009, 07:14 AM
ddlyspdr ddlyspdr is offline
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Default rear suspension ideas

so i was thinking on what kind of cart to build over the winter, and ive come to the conclusion it will be an off road style car, independent suspenion up front and some sort out back. has anyone tried making a rear suspension like a 3 or a 4 link?? like off road guys do it? you would have to worry about the axle twisting up to prevent the chain from twisting also, unless u mount the engine on the axle. ill post up more later
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Old 07-12-2009, 09:54 PM
ddlyspdr ddlyspdr is offline
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does anyone know what im getting at?? or do i just need to build it and show then??
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Old 07-12-2009, 10:00 PM
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Can you sketch up a idea of what you are wanting??

theo
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Old 07-12-2009, 10:13 PM
squat251 squat251 is offline
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i think he means like a swing arm with the motor mounted on it, the way it should be done, only with a pivot where the swing arm connects, so that it acts almost like independent
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Old 07-12-2009, 10:22 PM
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you would need to mount the engine to the axle some how so your not popin the chain off all the time.
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Old 07-12-2009, 10:53 PM
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Quote:
Originally Posted by squat251 View Post
i think he means like a swing arm with the motor mounted on it, the way it should be done, only with a pivot where the swing arm connects, so that it acts almost like independent
It would'nt act more like independent, It would act more like a solid axle on a truck. It would be like a swingarm, but it could Twist.

For the chain, You would just have to mount the engine and axle on the arm, so everything moves together.

I've seen some neat setups on some of the newer bigger go carts at TSC.

They have two swingarms, one for each wheel, and two sets of sprockets and chains.

I'll have to find pics of it sometime later.
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Old 07-13-2009, 01:18 AM
squat251 squat251 is offline
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to be completely honest thats where i got the thought of that set up, the carts a the nearish TSC (im just going to guess that they are older, not new ones like you would find in more populated areas.

and it sort of would, instead of hitting a solid object on one side and both moving up, one tire would go up, the other would shift more onto its side.
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Old 07-13-2009, 06:23 AM
frederic frederic is offline
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I'm still working out the rear suspension bits (on paper) for my son's kart, and I have crude designs for all three types depending on what parts I can acquire cheaply at the time I begin assembly.

If I end up with a cheap golf-cart axle a 4-link would be my choice because of ease of fabrication. If you do the four link it would be best to have a panhand (panhard) rod to keep the rear axle from shifting left and right, just like in a "real" car.

A central swing-arm is good for a live axle, and probably even a solid axle, though the axle will "roll" as it articulates. If designed well this can actually work to your advantage if you have enough "bite".

During hard acceleration, you'll have weight transfer off the front wheel to the rear wheels, which is good for traction. As the axle has traction, the swing arm suspension will be rolled the opposite way and in turn articulate downward as the axle rolls forward. If tuned right this roll will cancel the weight transfer and the vehicle will remain at ride height which may not be that important on a lower powered dirt kart but if one springs it correctly you can do some neat things here.

Me, I'd really like to do an independent rear suspension as well as a front suspension, and of course powering drive wheels in an IRS is much more complicated than a live axle or a golf cart axle.

But we'll see what parts I can get as for me that's going to determine what I do. I absolutely do not want to mount a live axle directly on the chassis and have the thing rock left and right as it travels over uneven terrain, like a riding mower does.
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Old 07-13-2009, 12:32 PM
squat251 squat251 is offline
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yeah, we are scoping out junkyards and friends to find a broken golfcart (preferably with a blown engine, as we want to replace it) we're going to put a sled engine on it and just lower the seats down to the floor for stability.
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Old 07-13-2009, 03:39 PM
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Quote:
Originally Posted by frederic View Post

Me, I'd really like to do an independent rear suspension as well as a front suspension, and of course powering drive wheels in an IRS is much more complicated than a live axle or a golf cart axle.
The setup I tried to describe earlier really is simple, and very easy to do compared to other IFS setups, where most need U-joints, or CV joints.

Just imagine a motorcycle swingarm and wheel, chain. But A swingarm on each side of the cart. Then the chains go up to a jackshaft.

The setup is actually pretty neat, You get all kinds of clearance, and each wheel has Tons of travel, Totally independent.
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Old 07-13-2009, 07:35 PM
ddlyspdr ddlyspdr is offline
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the setup i am trying to describe is like a rock crawler, 4-link with triangulated rear axle assembly so no panhard rod, the engine, gearbox, and axle all mounted on the rear end, the seat and front end a completely different end. this is not independant, or a swingarm style. i dont have the funds for a fully independant cart, but that would be nice. ill draw up some plans soon.
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Old 07-13-2009, 07:52 PM
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crude picture i know. all the details have not been thought thru
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Old 07-13-2009, 08:41 PM
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Ok I see you are talking about a swing arm sort of, attached to the frame by a 4 link.

theo
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Old 07-13-2009, 09:10 PM
ddlyspdr ddlyspdr is offline
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no swing arm at all. it will be a replica of an axle on a truck (minus a housing and diff) with the engine and gearbox on top, connected to the main part of the cart by a 4-link suspension setup.
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Old 07-13-2009, 09:16 PM
ddlyspdr ddlyspdr is offline
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crude drawings again. my microcrap paint skills suck.
side view.
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Old 07-13-2009, 09:39 PM
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Like this?
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Old 07-13-2009, 09:45 PM
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Quote:
Originally Posted by ddlyspdr View Post
no swing arm at all. it will be a replica of an axle on a truck (minus a housing and diff) with the engine and gearbox on top, connected to the main part of the cart by a 4-link suspension setup.

That is what I was sort of meaning only I called the assembly which everything is mounted to a swing arm.
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Old 07-14-2009, 04:34 PM
ddlyspdr ddlyspdr is offline
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yea its not called a swing arm tho. swing arm will need a panhard rod to keep it located to the rear. 4 link is just that 4 separate links mounted to the chassis and to the axle. triangulated 4links are set so you dont need to locate the axle, it will stay where it is.

ive thought about it tho, if you mount the motor and gearbox on the axle, the unsprung weight will probably be too much.
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Old 07-14-2009, 04:59 PM
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I was thinking a while back of something like this for the articulation, but it needs a couple of more links. The red circles are bearings and the front circle at the front bearing housing is a rod end.

What were you thinking of using for a gearbox?

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Old 07-14-2009, 05:41 PM
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Why would you need a u-joint, you could just mount the engine onto the arm itself.
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