LocostUSA.com

To stiffen it up I would add an 'X' brace. Start at the front seat mounts and go up about 12" or so connecting opposite side tube, that should remove nearly all the flex from the bend and still leave room for you legs to..... well I guess still hang in the middle of nowhere.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Hmm.. Adding some cross bracing in the gooseneck was an idea earlier that I ditched when I added the center tube.. I might still connect all that together. I like the idea of a cross brace in the angle. I think some triangulation may help as well.. Hahahaha!!!! There will be foot pegs added in as well as a hydraulic rear foot brake... Need to get the frame right first... Thanks for all the pointers.. Just finished helping a buddy rewire a 79 Jeep CJ5 and I have a little motivation left... Off into the garage I go...

I just built peddle powered drift trike myself, no pictures as it still needs painted. I used an old mountain bike as my starting point so my front frame is much beefier and welded my lower frame to the original pedal location on the mountain bike frame. No flex yet on mine. I would sit in the seat and add as big of gussets as you can to those front bends in the lower frame without bothering leg clearance.

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Build on

Chris
Build: NA Miata based +221 Se7en

Seems like a cross brace over the goose neck was the ticket. Flex is minimal now and even with the front wheel at full tilt the frame didn't lay on the ground. Time to move on to the motor mounts. Thanks again for all the wisdom and suggestions....

Your welcome!

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Where did you get your front wheel? I've been thinking about building one of these for some time but have not been able to find a locost big front wheel

From the first pictures, it looks like he cut up a brand new bike. Still has the protective wrap on the back end?

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Trochu Motor League

Good eyes, he also appears to have another wheel sitting there doing nothing.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

IMO 80-90% of the flex happens where I marked. You need to:

1- strap both the inner and outer curves there. Possibly using a next size up pipe- bent, then split and welded on. Splitting a bend lengthwise is probably a 3" cut off wheel job. .
2- possibly add a foot long bent-parallel adjoining tube just in that area, welded to the existing frame along its length. Inside would be best appearance wise, so cut it in two pces and fit the ends tight to your cross bar..& weld.
3- as mentioned, the overall lower frame is at very least a couple inches too low. It should have only a piece of paper's clearance to the bottom of the axle.

To answer the questions of where I got the tire. Yes it's a new mongoose from Amazon. $189 shipped. I have friends that race fat tire bikes and I couldn't piece together a front end for half that price with the parts that they are all familiar with. Also came with a front disc brake. It came with more than I need and an extra rim and tire to boot.

Ladr. The way the frame sits is where the bearing cassette brackets put the frame bars. The brackets are commercial and already fitted for tubing from BMI karts. I did no fabrication there other than welding the tubes up to them.

Just wanted to let everyone know.. I did get it completed, and running.. Myself and a couple neighbors and a couple friends took it out for pretty much the entire day and ran it through some paces.. It held up amazingly.. Chassis flex was no longer an issue, and it would only scrape if you tried to go over manholes.... HAHAHAHA!!!!! It was a little slow after you got used to it and hitting redline was easy, so I swapped the front sprocket to add about 11 mph. It The motor still has the stock governor.. It lost some torque but made up for it in the top end and its a BLAST!!!! Im going to run it around a few more times and beat on it to make sure there are no issues, then blow it apart to weld on a couple brackets and for paint.. Pictures will be coming soon....

EDIT: I just remembered that there were a few people interested in building one.. I still consider this to be pretty LoCost inspired.. I have been looking at companies that design and sell these.. $3200-$3800 seems to be the norm for a fat tire drift trike.. After adding up all my receipts, I am into this for just over $1400, and this is with the use of heavy duty and race parts, adding a hydraulic rear disc brake, purchasing a couple extra sprockets to adjust the gearing, and adding a few go fast parts for the motor.... Not bad....