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Go-Krawler Flatfender - Articulating 4x4 Go-Kart

Exciting stuff coming to this thread soon. A pile of aluminum arrived this week, the main chassis is already coming together pretty fast. I have the rear half of the chassis rough assembled too, but no pics of that yet until I start connecting it to the front

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JR4X said:
Those little gear boxes are pretty cool. Did you see the go-kart I retrofitted one of those into for my step kid when I was playing parent?
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Don’t mean to sidetrack but what the hell why does that video have 122k views? I mean rad cart but random haha
 
fl0w3n said:
Don’t mean to sidetrack but what the hell why does that video have 122k views? I mean rad cart but random haha
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If it is under a minute it will show up as a short, and will get lots of views. I posted a video of my truck driving up some trail years ago and it went from like 12 to 6k views in a day or two because it got converted to a short. Social media is scary when you realize 122k people you don't know watched your kid drive his golfcart.
 
fl0w3n said:
Don’t mean to sidetrack but what the hell why does that video have 122k views? I mean rad cart but random haha
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I don’t know exactly what happened or how. For some reason that video went crazy on Facebook in India. I put it on Facebook, Someone shared it with a go kart group and it exploded. I was getting messages on messenger in languages I don’t speak, asking me how they could do it. I have a build thread on that kart on PBB. I used to just share the link to the thread because it had build pics and videos.

Sorry for the highjack Agitated. Loving the build.
 
That is rad, sweet to see one in use. From what I’ve gathered the gearboxes seem to have a decent reputation, and you can’t beat the price so I’m pretty pumped.

Don’t sweat the side track at all haha, funny how the algorithms work sometimes. Especially odd that you got so much traffic from other countries, but cool nonetheless. Was that thing predator 212 powered? And this is a stretch, but any clue what it weighed?
 
AgitatedPancake said:
That is rad, sweet to see one in use. From what I’ve gathered the gearboxes seem to have a decent reputation, and you can’t beat the price so I’m pretty pumped.

Don’t sweat the side track at all haha, funny how the algorithms work sometimes. Especially odd that you got so much traffic from other countries, but cool nonetheless. Was that thing predator 212 powered? And this is a stretch, but any clue what it weighed?
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It is just a predator 212. I never weighed it but I don’t think it could have weighed over 200 pounds. I could put it in the bed of a truck by myself. I built it for an 8 year old and it served its purpose well, he tore the shit out of yard and the cart which was exactly what I wanted. Now he can’t even fit in it. That gearbox was an excellent part. Shifted perfectly, even the 6 year olds could drive it. The CVT worked better than I would have imagined.
 
Basically have the body assembled, really happy with how it has all come together. Have a bit of concern that I have undersized the differentials, so I may have to draw up another iteration of a couple axle related components with larger diffs, just in case these end up failing.

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TrailTamer said:
Why? I think it will live a long life as it’ll only be used to stop spinning to shift forward/reverse gears.

no brakes needed with worm gears, most likely tires will lock up all on its own when throttle is released.
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That effect from worm drives all depends on the ratio. At the numerically low 5:1 ratios I have for the differentials, they're pretty backdriveable per the mfg. They have a ranking system for how resistant they are, and they say this ratio is pretty low compared to others. I definitely expect there to be some braking effect still, but i don't know how intense it will be until I get it mobile
 
Thank for sharing. I don’t know what exact gear box you’re going with but I certainly will approach this with caution, unless you’re ok with or it was intentional to have little to no “neutral” effect and need car dollies to move it around, like “hydromatic” riding mowers which is damn near impossible to roll unless you pull its little rod out back to free spin to push around.

What ratio, by the way?
 
TrailTamer said:
Thank for sharing. I don’t know what exact gear box you’re going with but I certainly will approach this with caution, unless you’re ok with or it was intentional to have little to no “neutral” effect and need car dollies to move it around, like “hydromatic” riding mowers which is damn near impossible to roll unless you pull its little rod out back to free spin to push around.

What ratio, by the way?
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It's definitely something I'm approaching with caution, as I don't have a good feel for how drastic it's going to be with these boxes. The ratio is 5:1, and that reversibility number goes down drastically (more resistant to backfeed) as you get into deeper ratios, so we will see. If these diffs do end up failing early due to being undersized, I am also considering bevel gearboxes from quads as the next iteration, depending on how intense this inherent braking function ends up being

wvracer821 said:
Wouldnt the CVT allow it to roll around freely?
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The resistance to being backdriven would come from the differentials themselves, so the worm drive wouldn't allow the tires to spin the input gear so the backfeed wouldn't even make it up to the rest of the powertrain. It'll be a learning experience either way hah
 
wvracer821 said:
Wouldnt the CVT allow it to roll around freely?
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The CVT free spin fine and well, as seen on mini bikes, go karts, snowmobiles and more. My concern about worm gears, even with backdriveability, will have undesired braking effect due to drivetrain components between gear box and CVT wanting to come to a stop whenever engine is not driving the CVT.

One way to find out! As a rock crawler go-kart it may be appreciated after all…
 
I'm not fully committing to anything, BUT... once you get the bugs worked out and have a production version I will probably want one. As will MANY other dudes.

It would also be worth your time to patent some of the design elements, such as the one-link suspension with the engine and gearbox mounted.

I could see this taking off and becoming a business if you wanted to take it that far.
 
TrailTamer said:
One way to find out! As a rock crawler go-kart it may be appreciated after all…
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Honestly for the low speed stuff I think it very well could be a bonus, but I don't want to make sacrifices in higher speed comfort, so I'm right there with ya in just feeling out how it ends up handling

Yotota said:
I'm not fully committing to anything, BUT... once you get the bugs worked out and have a production version I will probably want one. As will MANY other dudes.

It would also be worth your time to patent some of the design elements, such as the one-link suspension with the engine and gearbox mounted.

I could see this taking off and becoming a business if you wanted to take it that far.
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Sweet. Honestly it's something I would consider. It may price itself out of competition, but that's all part of the discovery process of this #1
 
AgitatedPancake said:
Basically have the body assembled, really happy with how it has all come together. Have a bit of concern that I have undersized the differentials, so I may have to draw up another iteration of a couple axle related components with larger diffs, just in case these end up failing.

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That body looks amazing and I’d be possibly interested in one for my little dude later down the road.
 
Time to show the drivetrain as well I suppose hah, this configuration is currently getting scruitinized and improved for larger differentials. The engine and CVT sit on their own tray with slotted engine mount holes so belt tension can be adjusted. Then that complete tray unit gets bolted to the central “axle” with slotted bolt holes to adjust chain tension down to the rear driveline (which drives the whole 4wd system). I designed for the knuckles to ride on bronze bushings, lowers are mocked up but uppers need a little problem solving. Rear of vehicle is at the top of the images, front at the bottom

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AgitatedPancake said:
Time to show the drivetrain as well I suppose hah, this configuration is currently getting scruitinized and improved for larger differentials. The engine and CVT sit on their own tray with slotted engine mount holes so belt tension can be adjusted. Then that complete tray unit gets bolted to the central “axle” with slotted bolt holes to adjust chain tension down to the rear driveline (which drives the whole 4wd system). I designed for the knuckles to ride on bronze bushings, lowers are mocked up but uppers need a little problem solving. Rear of vehicle is at the top of the images, front at the bottom

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🤤
 
AgitatedPancake said:
Thanks guys, I'm pumped.



It's a worm gearbox as well, you can kinda see it in the image of the pedal box. It'll have around 1.5 turns lock to lock, something like 30 degrees of steering
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Nice, so it should have minimal kickback (depending on the back drive ratio as discussed earlier for the diffs).

I'm definitely curious to hear how this works out from a cost perspective. If you ever scale up you could hopefully get some bulk discounts in order to reduce the material and parts cost, and you'll of course get faster to produce the proprietary components. Valuing your time correctly and covering your R&D costs, while making some profit, will be the kicker.
 
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