Can't wait to see some clones of this....

[Russell ATV]

I would love to try and build one of them. The idea of a very compact off road go kart appeals to me enormously. I just wish i could see some more comprehensive instructions to try and guess what building one would really cost...

I cannot agree more, that is why I am working to produce a kart that is similiar (compact with a suspension), but do it at a reasonable price. I thick the fact that most manufacturers have abondoned the simple no roll cage kart for these giant, expensive buggies is an opportunity to capture purist and people looking for accessable (easy to move, easy to store, budget priced) fun.

The Trail Ripper is probably about $200-$250 to make in volume. The seat appears to be pulled from boating, and it is ugly.

As for putting springs on it, you would then need to add spring support towers, reinforce the arms, and add weight, weight, and more weight. The Trail Ripper only weighs about 80lbs. I thought the suspension was a bit firm, but looking at the videos, it appears very effective.

Russ Barrow
Russell ATV

 

[rgvkid]

The suspension looks like it works great and its such a simple design. If you look at the diagram i posted it gives you all the info on material that you could just order online. The only thing about the suspension would be the trial and error of finding the degrees on how to mount the arms from the suspension knuckle to the hubs. Plus the engine is more compact and light weight being that it is a smaller go ped engine.

The chair, they sell it at wall-mart online marine department.

 

[Justin]

That looks like a fun, simple, cheap build. If i didnt have a summer job i would build one.

 

[ChadClancy]

You can buy Urethene bars for pretty cheap on the net. If you look at the diagram its pretty simple design. Way over priced to buy new.

Yea, they shouldn't have spec'd it out in the parts diagram so completely. You can find 90 durometer (hardness) 5/8" urethane rod HERE for a good price (relatively to what they want for the part). This was the first one I came across, you could probably find it for less by shopping around.

As a group, we should try to replicate this type of suspension and come up with a good reverse engineered design.

 

[Kenny_McCormic]

Instead of the rubber setup you could do it RusselATV style, jut make parts of the swing arm and front axles from spring steel. That's how I would do it.

 

[ChadClancy]

The nice thing about the urethane is that you could set it up with urethane bars of different hardness to fine tune the suspension for the kind of ride you are looking for. It would be neat to try the bars with a softer and harder rating than the 90 durometer used by this kart and see how the ride changes and which ones work best for the terrrain you drive your kart in. Also, you could use different bars in the front and rear if that made for the best ride.

After looking at the swing arms in the diagram, it looks like they would be pretty easy to make. It looks like the urethane bars sit in the corners of the outside tube and the knuckle has a square tube rotated at a 45 degree angle within the outer tube. The key would be to properly size the outside and inside tubular members (width and thickness) and to make sure that the weldments were strong enough to handle the torque.

The swing arms are just a piece of tube with a channel on the knuckle side bolted to the knuckle and the other end looks like a standard spindle setup.

 

[rgvkid]

Im picking up some Urethane bar from Mcmaster Carr today for my push trailer project. I'll post soon the details on how it turns out using the urethane suspension.

 

[Scorch3]

Im picking up some Urethane bar from Mcmaster Carr today for my push trailer project. I'll post soon the details on how it turns out using the urethane suspension.

Can't wait to see how this works for you.

 

[ChadClancy]

Anyone else want to try?

Here is a link to some inexpensive urethane rod (95 A hardness) on ebay. $8 for a 24" length of rod (plus shipping).

 

[rgvkid]

Thats cheap, I paid alot more then that at mcmaster carr for a 24 ft. length.

 

[ChadClancy]

Thats cheap, I paid alot more then that at mcmaster carr for a 24 ft. length.

Do you have any thoughts on the size of the outer housing and the part of the knuckle that fits between the rods?

It's hard to tell for sure how these items are sized but we do know the diameter of the rods. The attached image shows what I had envisioned. That would make the inside dimension of the housing about 2 inches and the knuckle bar 1.375 inches. Does this look plausible?

 

[rgvkid]

Great drawing. Im think the insert rod is 1/2 inch, and the outer is probably about 1.5in. I have alot of scrap in the shop so i will let you know what works together in dimensions when i get the rod. It shoul dbe arriving today, it had to be shipped. here is the link to the Go ped diagram. Its the trq quad and the trail ripper that use this suspension setup. I don't know anyone who has an offroad go ped, if i did i would ask if we could take apart the suspension housing to get a better idea of components. Also a thread a started on the Goped forum.

With this setup, an 1/8 twist in the suspension housing can eqaul out to like three inches of travel down the line of the swing arm.

http://www.gopednation.com/forum/showthread.php?t=266733&highlight=TRQ

http://www.goped.com/shop/trq_list.asp

 

[ChadClancy]

1.5 inch square tube would be too small if the insert rod is 1/2 inch. If it the outer tube has an inside diameter of 1.5 inches, with a 1/8" wall, that would make it 1 3/4" tube and that would make the insert about 0.6" square.

 

[oscaryu1]

Look like another 49cc go kart. Wonder how long the clutch would last with 400 pounds of... people?

 

[Scorch3]

Thanks for the Diagram ChadClancy. I was thinking of this the wrong way this is way simpler than i thought. Maybe i will try building one... once i finish my mini bike.

 

[modelengineer]

The inner square 'tube' looks like a solid bar which is machined square. This means it's almost certainly not a standard size. I would think that you buy some outer square tube, then machine the inner square piece so that the measurement across its diagonals is *just* less than the size of the square tube, so it can rotate around.

 

[ChadClancy]

The inner square 'tube' looks like a solid bar which is machined square. This means it's almost certainly not a standard size. I would think that you buy some outer square tube, then machine the inner square piece so that the measurement across its diagonals is *just* less than the size of the square tube, so it can rotate around.

That's what I initially had in mind but if the outer tube size is smaller than about 2 inches, you wouldn't be able to fit the inner piece between the urethane rods. The basic idea is right but you have to assume an outer tube size, place the rods in each of the corners and measure/compute the diagonal distance between the rods to determine the machined size of the inner piece. (keep in mind that we know the diameter of the urethane rods so that dimension is "fixed")

The other thing to consider is that if you use too small of an outer tube, the inner piece gets smaller such that when it rotates, you might get contact on the urethane with a sharp corner of the inner rod which could tear into the rod. To avoid this, the inner piece has to be at least about 1" square. This would make the inside diameter of the tube about 1.75"

 

[Scorch3]

Someone should join their forums. I'm sure someone on there would be happy to snap a couple pics or even explain the suspension a little bit more. Who knows you might even be lucky enough to have someone give you some exact dimensions.

 

[Persistant]

Hey guys!
Has anyone made any progress yet on building this quad with the urethane rod suspension? I'm very close to just digging in and starting on it. I would just like to get some sizes for the frame and the suspension knuckle, and to see if anyone had some success with this.

Any dimensions would be great to get me going on the frame.
Thanks!

 

[Buick455]

Do you have any thoughts on the size of the outer housing and the part of the knuckle that fits between the rods?

It's hard to tell for sure how these items are sized but we do know the diameter of the rods. The attached image shows what I had envisioned. That would make the inside dimension of the housing about 2 inches and the knuckle bar 1.375 inches. Does this look plausible?

i havent been on in a while but i came in for a look to see what eveyone is up too and i lightbulb poped up when i seen your pic, lol..

i dont know how available it is (or if its even been thought of by any of ya) but big excavation equiptment use these big a$$ rubber belts, got to be at least 1/2 round if i remember correctly, that get streched out and need to be replaced.. we use to use them as bungee type rubber bands as kids for slingshots (hook them to 2 trees across the driveway pull tommy back in the wagon and let him go type of sillyness) they would be good i think for you drawing cut into rods.. just my 2 cents

also i would try and dimple the 4 flat sides of the center bar in order to get a tighter fit..