Driving problems in 4-wheel indep suspension

[zoelo01]

Driving wheel bouncing problems in a 4-wheel indep suspension go kart

The problem is the bouncing of the driving wheel causes bang when speed is over 10 mph! How to fix it. I try to adjust the shock tension but no help at all!

After some modifications, the bouncing problem occurs when the engine is in low speed. When the engine reaches some certain speed, the problem is gone!

 

[2SlickNick]

Maybe longer, stiffer shocks.

Edit, also vehicle type, shock lengths , type, aftermarket, and pics all help in us aiding your problem.
Also fill in your profile location, your terrain helps in problem slving too.

PS- looks like your first post, so......

 

[fowler]

Little sense is made

I presume is a one wheel drive cart

And the wheel is comeing off the ground

Possibly worn out shocks

 

[zoelo01]

Oops! Here is the picture:https://drive.google.com/file/d/0B_pfua0s8nvcQWZBaXVhZG1ZU0k/edit?usp=sharing

2SlickNick: I built the cart. Yes, this is my first post.

Fowler: Yes. It's one wheel drive. The shocks are new.

I did a test by lifting up the driving wheel, and stepped on the gas. It was running without any problem. While driving, I keep an eye on the driving wheel. When the speed increases, I see the tire bouncing fiercely, and the cart starts to bang loudly.

 

[2SlickNick]

That is a awesome setup. I would live to fav up one in a dual wheel drive.

 

[OzFab]

I think we need to see more pics of the whole kart, your problem may have nothing to do with the drive wheel, it may be caused by something else reacting to it...

 

[firemanjim]

Wait... What? You built THAT but only made it one wheel drive? Uhh, why?
Post some more pics..... It's not the drive wheel... I think its the whole set up, as Fabroman is suggesting. I'd like to see a pic of the pivot point for sure, and what the whole rear end looks like as well as an overview of the kart.....
We might see what you're missing.....
Oh, and
I like what I saw, and have a design for something similar, just dual wheel drive and single sided swing arm.....
Please fill in your location.....

 

[fowler]

Bent axle maybe

I think torque though the chain is pulling the drive wheel off the ground
Or instead of spinning the wheels it's bouncing
Like diff hop when u take a solid axle 4x4 off road

A video would be best

Or fit a solid shock absorber
So measure the length of the shock when the kart is on the ground

Then get a peice of metal and put two holes in it at that length and fit it where the shock was

If the kart still bounces after that then u have a bigge promblem else where in the frame

Anougther test
Get something quite heavy like an old car battery and secure it to the trailing arm

As close as prossible to the bottom

This will put more weight on the wheel and may eliminate a few variants
Like the hopping as the power goes down

Perform the weight test first
Report results with more pics and we can find a better solution from there


EDIT

There are a few things I see need amending from that pic
Like no crush tube where the axle mounts

But we'll worry about those later

 

[firemanjim]

You might have hit it on the head, Fowler. The drive torque,plus terrain...... Ahh yes,just hitting the throttle, with no shock,would pull the wheel assembly up! Did not even consider that! Good call!
Yep need more pics, and I would try the solid bar in place of shock test, to see if that is indeed what was happening. If it is, add drive to the other wheel as well, and problem might be eliminated. Add a lot stiffer shock to that one side, if left as one wheel drive....
He don't need a crush tube with 1/8th inch thick tube.....
EDIT.... With that eagle eye and brain of yours, Fowler, your obviously not from Canada..... (its okay, Doug. He ain't one of "them"..... )

 

[2SlickNick]

I too would like to see the kart as a whole from iter angles and set up.
Might I suggest shocks for a Yamaha blaster or a snow mobile. Plus your shocks appear to be the pogo stick stock mecanical type. Some gas resistance and maybe adding a trail arm weight maybe like 15 pounds and adjust( by adding or removing weight) as needed.

All in my opinion of course. American sportswoman sells a decet type of gas shock too. It comes on the Carbde 150cc.
I think anything is an upgrade from just a spring.

Plus by adding weight will give you numbers( I.E. if those mechanical shocks are rated to 70
lbs an you add 30 lbs if lead and that solves our problem then you know a 100 lbs coil is somewhere in the ballpark

 

[firemanjim]

American Sportswoman?
They sell training bras too....

 

[2SlickNick]

American Sportswoman?
They sell training bras too....

LMAO, **** spell check is killing me....

 

[zoelo01]

More pictures

https://drive.google.com/file/d/0B_pfua0s8nvcWnpHcGlGMU1Wdk0/edit?usp=sharing
https://drive.google.com/file/d/0B_pfua0s8nvcazZjVmFGekhxZ1E/edit?usp=sharing
https://drive.google.com/file/d/0B_pfua0s8nvcbExkRUhHOUdXOGs/edit?usp=sharing
https://drive.google.com/file/d/0B_pfua0s8nvcWVNFODR4Qm5aMmM/edit?usp=sharing

Note: The problem exists after the cart was built. So it should be some structural issue.

 

[zoelo01]

That is a awesome setup. I would live to fav up one in a dual wheel drive.

Thanks! BTW, what is fav?

 

[zoelo01]

Wait... What? You built THAT but only made it one wheel drive? Uhh, why?

It's one wheel drive because I want to get rid of differential axle issue. One wheel drive does not have that problem.

 

[zoelo01]

Bent axle maybe

I think torque though the chain is pulling the drive wheel off the ground
Or instead of spinning the wheels it's bouncing
Like diff hop when u take a solid axle 4x4 off road

This is what I suspect too. When the wheel is off the ground, the driving force is fully applied to the sprocket. At the moment when the wheel touches the ground, the friction causes the sprocket and the chain to kick and make a bang along with shacking/vibration.

A video would be best

Or fit a solid shock absorber
So measure the length of the shock when the kart is on the ground

Then get a peice of metal and put two holes in it at that length and fit it where the shock was

If the kart still bounces after that then u have a bigge promblem else where in the frame

I did a similar test by adjusting the shock to the highest strength but it did not help. My guess is that the other 3 shocks will still give the driving wheel chances to bounce. The problem remains.

Anougther test
Get something quite heavy like an old car battery and secure it to the trailing arm

As close as prossible to the bottom

This will put more weight on the wheel and may eliminate a few variants
Like the hopping as the power goes down

Perform the weight test first
Report results with more pics and we can find a better solution from there

This is interesting. I start to feel that the shocks are too strong for this cart. If the shocks are soft enough to support the load, all 4 wheels should not be bouncing and should be touched the ground all the time.
BTW, how do you perform a weight test?

 

[fowler]

U may have to weld a braket on

I dout the shocks are too soft
This would lead to something breaking

Basically u must get as much weight as possible over the trailing arm
With in reason

You may have to weld a (shelf) to mount weight

EDIT
You can probs bolt something to that bracket u have welded to the back

 

[2SlickNick]

Thanks! BTW, what is fav?

Fab... Spell check strikes again.

 

[2SlickNick]

U may have to weld a braket on



You may have to weld a (shelf) to mount weight

I like this idea. You can add weights in seconds to adjust to any terrain.
Also you will able to obtain statistics from your baseline findings.
Having a proper baseline is the start to any real improvements or gains on modifications.

When I attempt a kart with suspension, project. I might need to weld two HD bolts maybe 5 inches or so, maybe use workout weights....

 

[zoelo01]

I like this idea. You can add weights in seconds to adjust to any terrain.
Also you will able to obtain statistics from your baseline findings.
Having a proper baseline is the start to any real improvements or gains on modifications.

When I attempt a kart with suspension, project. I might need to weld two HD bolts maybe 5 inches or so, maybe use workout weights....

I will try to replace the shock with a stock later.
Updates: I step on the driving wheel york (I am 165 lbs) but the problem is still there